Related
5.13
We made tweaks on my.cnf according to mysql tuner, and tuning primer,
but i can't really figure out when the memory will be stabilize usage of mariadb.
Here mysql tuner result -
------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 5d 8h 19m 28s (226M q [491.299 qps], 1M conn, TX: 4653G, RX: 49G)
[--] Reads / Writes: 95% / 5%
[--] Binary logging is disabled
[--] Physical Memory : 125.3G
[--] Max MySQL memory : 67.1G
[--] Other process memory: 0B
[--] Total buffers: 15.4G global + 264.8M per thread (200 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 34.3G (27.34% of installed RAM)
[OK] Maximum possible memory usage: 67.1G (53.54% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (78/226M)
[OK] Highest usage of available connections: 36% (73/200)
[OK] Aborted connections: 0.02% (447/1823123)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (4K temp sorts / 56M sorts)
[!!] Joins performed without indexes: 815533
[!!] Temporary tables created on disk: 87% (26M on disk / 30M total)
[OK] Thread cache hit rate: 99% (73 created / 1M connections)
[OK] Table cache hit rate: 99% (286M hits / 287M requests)
[OK] table_definition_cache(37000) is upper than number of tables(36204)
[OK] Open file limit used: 69% (51K/74K)
[OK] Table locks acquired immediately: 99% (170M immediate / 170M locks)
Here tuning primer -
WORKER THREADS
Current thread_cache_size = 200
Current threads_cached = 72
Current threads_per_sec = 0
Historic threads_per_sec = 0
Your thread_cache_size is fine
MAX CONNECTIONS
Current max_connections = 200
Current threads_connected = 1
Historic max_used_connections = 73
The number of used connections is 36% of the configured maximum.
Your max_connections variable seems to be fine.
INNODB STATUS
Current InnoDB index space = 1.46 G
Current InnoDB data space = 10.79 G
Current InnoDB buffer pool free = 24 %
Current innodb_buffer_pool_size = 15.00 G
Depending on how much space your innodb indexes take up it may be safe
to increase this value to up to 2 / 3 of total system memory
MEMORY USAGE
Max Memory Ever Allocated : 15.76 G
Configured Max Per-thread Buffers : 1.71 G
Configured Max Global Buffers : 15.14 G
Configured Max Memory Limit : 16.85 G
Physical Memory : 125.34 G
Max memory limit seem to be within acceptable norms
Here a sample of resources from top since start up until 5 days and 8 hours uptime of mariadb -
mysql 20 0 21.4g 4.1g 24576 S 4.7 3.3 0:08.90 mariadbd
mysql 20 0 21.4g 4.8g 25728 S 4.7 3.8 2:13.62 mariadbd
mysql 20 0 25.9g 8.7g 26480 S 15.0 6.9 56:52.91 mariadbd
mysql 20 0 26.2g 8.8g 26480 S 3.7 7.0 58:37.38 mariadbd
mysql 20 0 26.7g 9.3g 26480 S 10.6 7.4 66:38.53 mariadbd
mysql 20 0 26.7g 9.3g 26480 S 6.3 7.4 76:34.20 mariadbd
mysql 20 0 26.9g 9.6g 26480 S 10.0 7.7 80:31.37 mariadbd
mysql 20 0 26.9g 9.8g 26480 S 10.3 7.8 95:36.03 mariadbd
mysql 20 0 27.4g 10.2g 26480 S 8.0 8.1 96:28.67 mariadbd
mysql 20 0 27.7g 12.4g 26496 S 2.7 9.9 127:20.78 mariadbd
mysql 20 0 27.7g 15.0g 26496 S 11.3 12.0 129:35.15 mariadbd
mysql 20 0 27.7g 16.3g 26492 S 4.7 13.0 130:34.33 mariadbd
mysql 20 0 27.7g 16.3g 26492 S 22.9 13.0 135:47.21 mariadbd
mysql 20 0 27.7g 16.4g 26460 S 13.3 13.1 182:57.25 mariadbd
mysql 20 0 27.7g 16.9g 26436 S 5.0 13.5 186:18.78 mariadbd
mysql 20 0 28.2g 17.4g 26436 S 27.9 13.9 220:29.14 mariadbd
mysql 20 0 28.2g 17.4g 26436 S 10.3 13.9 240:20.25 mariadbd
mysql 20 0 28.6g 17.8g 26436 S 15.9 14.2 242:50.85 mariadbd
mysql 20 0 28.6g 17.9g 26436 S 6.6 14.2 244:48.40 mariadbd
mysql 20 0 29.0g 18.3g 26436 S 5.0 14.6 271:35.53 mariadbd
mysql 20 0 29.4g 18.5g 26480 S 11.6 14.7 327:44.08 mariadbd
mysql 20 0 29.8g 18.9g 26480 S 21.6 15.1 328:47.99 mariadbd
mysql 20 0 29.8g 18.9g 26480 S 3.7 15.1 340:27.10 mariadbd
mysql 20 0 29.8g 18.9g 26480 S 7.0 15.1 360:15.26 mariadbd
mysql 20 0 30.2g 19.6g 26460 S 3.6 15.7 397:31.67 mariadbd
mysql 20 0 31.4g 20.1g 26460 S 6.6 16.1 424:18.82 mariadbd
mysql 20 0 31.8g 20.6g 26460 S 1.7 16.5 434:33.15 mariadbd
mysql 20 0 31.8g 20.7g 26460 S 12.3 16.5 474:25.23 mariadbd
mysql 20 0 32.1g 21.1g 26444 S 9.6 16.9 501:38.46 mariadbd
mysql 20 0 32.1g 21.1g 26448 S 14.0 16.9 509:05.98
mysql 20 0 32.5g 21.6g 26448 S 10.3 17.2 524:06.26 mariadbd
mysql 20 0 33.0g 22.0g 26448 S 7.0 17.6 527:11.55 mariadbd
mysql 20 0 33.5g 22.5g 25612 S 29.9 17.9 578:12.81 mariadbd
mysql 20 0 33.5g 22.5g 25612 S 2.3 18.0 580:04.96 mariadbd
mysql 20 0 34.4g 23.4g 25044 S 17.9 18.7 647:25.39 mariadbd
mysql 20 0 35.3g 24.5g 25272 S 10.0 19.5 753:34.30 mariadbd
mysql 20 0 35.7g 24.9g 25272 S 10.0 19.9 766:17.57 mariadbd
if im trying to determine the memory usage via service status the following result -
service mariadb status
Redirecting to /bin/systemctl status mariadb.service
● mariadb.service - MariaDB 10.5.13 database server
Active: active (running) since Mon 2022-01-03 03:03:15 IST; 5 days ago
Docs: man:mariadbd(8)
https://mariadb.com/kb/en/library/systemd/
Main PID: (mariadbd)
Status: "Taking your SQL requests now..."
Tasks: 87 (limit: 820947)
Memory: 37.4G
now i just see so many indiffrent current memory usage, and for example tuning primer returns -
Configured Max Memory Limit : 16.85 G
but mysql tuner returns -
[OK] Maximum reached memory usage: 34.3G (27.34% of installed RAM)
[OK] Maximum possible memory usage: 67.1G (53.54% of installed RAM)
attaching my.cnf configurations -
performance-schema=0
#innodb_buffer_pool_size=134217728
max_allowed_packet=268435456
open_files_limit=74000
innodb_file_per_table=1
unix_socket=OFF
max_connections=200
#wait_timeout=600
#interactive_timeout=600
##
innodb_buffer_pool_size=15G
max_heap_table_size=128M
tmp_table_size=128M
#max_connections=400
table_open_cache=37000
table_definition_cache=37000
thread_cache_size=200
key_buffer_size=128M
sort_buffer_size=1M
read_buffer_size=4M
read_rnd_buffer_size=512k
join_buffer_size=3M
##
But as you can see, top command returns 24.9gb ram usage, and service status returns 37.4GB ram usage? and tuning primer saying max memory is 16.85GB, but mysql tuner says 67.1GB?
I'm completly lost in this one..
when the memory will build up until getting a stabilize memory usage?
why tuning primer, and mysql tuner memory usage is so different?from the current usage of the server itself for mariadb service?
Could anyone share his tought regards it?
Thanks!
Edit -
Hey thanks for the reply, it just keep increasing after 7 and half days -
mysql 20 0 36.2g 25.4g 25280 S 10.3 20.3 811:15.91 mariadbd
mysql 20 0 36.7g 25.8g 25296 S 5.0 20.6 840:23.93 mariadbd
mysql 20 0 37.1g 26.3g 25296 S 3.3 20.9 843:11.06 mariadbd
mysql 20 0 37.1g 26.3g 25296 S 7.6 21.0 846:27.98 mariadbd
mysql 20 0 37.1g 26.5g 25296 S 14.9 21.1 898:34.45 mariadbd
mysql 20 0 37.2g 26.5g 25272 S 13.0 21.1 933:06.45 mariadbd
mysql 20 0 37.2g 26.5g 25260 S 25.0 21.2 956:38.96 mariadbd
mysql 20 0 37.6g 26.9g 25260 S 4.3 21.5 992:54.48 mariadbd
mysql 20 0 38.0g 27.4g 25252 S 17.5 21.9 1068:31 mariadbd
mariadb.service - MariaDB 10.5.13 database server
Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/mariadb.service.d
└─migrated-from-my.cnf-settings.conf
Active: active (running) since Mon 2022-01-03 03:03:15 IST; 1 weeks 0 days ago
Docs: man:mariadbd(8)
https://mariadb.com/kb/en/library/systemd/
Main PID: 4105634 (mariadbd)
Status: "Taking your SQL requests now..."
Tasks: 86 (limit: 820947)
Memory: 41.0G
total used free shared buff/cache available
Mem: 128350 35498 9313 2356 83538 89236
Swap: 0 0 0
systemd service status 37.4G looks consistent with the 35.7g figure from top (GiB vs GB perhaps explains the differences).
The 24.9G in top is the amount paged it. The difference to 37.4G is memory not paged in (or perhaps swapped out).
Tuning primer's 16.58G looks like it hasn't accounted all threads memory usage
mysqltuner's maximum looks like it has taken the pessimistic allocation of the maximum possible per thread allocation, which isn't occurring because your workload evidently doesn't to all the things that would get to this figure.
If your 5 days of uptime is pretty consistent to your workload, then 35/37G looks to be about the maximum used.
The thing that would make it rise from this point is if your 24% free buffer pool gets used. Your tuning primer shows 24% free which on 15G gives another 3.6G of potentially memory used on our current workload.
MySQL Tuner full from around 3h ago -
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 7d 9h 28m 52s (316M q [495.709 qps], 2M conn, TX: 6533G, RX: 69G)
[--] Reads / Writes: 95% / 5%
[--] Binary logging is disabled
[--] Physical Memory : 125.3G
[--] Max MySQL memory : 67.1G
[--] Other process memory: 0B
[--] Total buffers: 15.4G global + 264.8M per thread (200 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 34.3G (27.34% of installed RAM)
[OK] Maximum possible memory usage: 67.1G (53.54% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (111/316M)
[OK] Highest usage of available connections: 36% (73/200)
[OK] Aborted connections: 0.02% (605/2516029)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (6K temp sorts / 78M sorts)
[!!] Joins performed without indexes: 1135010
[!!] Temporary tables created on disk: 87% (36M on disk / 41M total)
[OK] Thread cache hit rate: 99% (73 created / 2M connections)
[OK] Table cache hit rate: 99% (398M hits / 400M requests)
[OK] table_definition_cache(37000) is upper than number of tables(36425)
[OK] Open file limit used: 69% (51K/74K)
[OK] Table locks acquired immediately: 99% (242M immediate / 242M locks)
-------- Performance schema ------------------------------------------------------------------------
[--] Performance schema is disabled.
[--] Memory used by P_S: 0B
[--] Sys schema isn't installed.
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is enabled.
[--] Thread Pool Size: 36 thread(s).
[--] Using default value is good enough for your version (10.5.13-MariaDB)
-------- MyISAM Metrics ----------------------------------------------------------------------------
[OK] Key buffer used: 99.7% (127.6M used / 128.0M cache)
[OK] Key buffer size / total MyISAM indexes: 128.0M/1.3G
[OK] Read Key buffer hit rate: 99.9% (3B cached / 1M reads)
[!!] Write Key buffer hit rate: 43.1% (31M cached / 13M writes)
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 15.0G/12.2G
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (0.625 %): 96.0M * 1/15.0G should be equal to 25%
[--] Number of InnoDB Buffer Pool Chunk : 120 for 1 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 99.99% (7707381322 hits/ 7708055862 total)
[!!] InnoDB Write Log efficiency: 335.3% (2710443 hits/ 808371 total)
[OK] InnoDB log waits: 0.00% (0 waits / 3518814 writes)
-------- Aria Metrics ------------------------------------------------------------------------------
[--] Aria Storage Engine is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/896.0K
[OK] Aria pagecache hit rate: 97.8% (1B cached / 30M reads)
-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.
-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.
-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] Binlog format: MIXED
[--] XA support enabled: ON
[--] Semi synchronous replication Master: OFF
[--] Semi synchronous replication Slave: OFF
[--] This is a standalone server
Heres tops -
top - 17:06:15 up 67 days, 14:15, 1 user, load average: 2.88, 2.79, 2.77
Tasks: 560 total, 3 running, 557 sleeping, 0 stopped, 0 zombie
%Cpu(s): 4.0 us, 0.6 sy, 0.1 ni, 95.3 id, 0.0 wa, 0.0 hi, 0.1 si, 0.0 st
MiB Mem : 128350.7 total, 7895.4 free, 35970.4 used, 84484.8 buff/cache
MiB Swap: 0.0 total, 0.0 free, 0.0 used. 89024.2 avail Mem
nothing except mariadb using alot of memory, some LSPHP proccesses spawn and go as for php requests to sites hosted within the server but they using memory only for proccesing the requests and then releasing it..
but overall cpu average is around 3-12% cpu usage, so server not under heavy load.
Server specs -
Intel xeon w-2295
software raid 1 with 2 NVMEs hard drives
OS - Cloudlinux 8.5 (based of almalinux 8.5 + redhat)
server using cPanel with mariadb 10.5.3 of cPanel.
128GB ram ecc memory
SELECT COUNT() FROM information_schema.tables;
COUNT()
94
Proccess list -
Show MySQL Processes
Id User Host db Command Time State Info Progress
root localhost NULL Query 0 starting SHOW PROCESSLIST 0.000
sometimes you see around 4-14 proccessess in the proccess lists.
Variable_name
Value
alter_algorithm
DEFAULT
analyze_sample_percentage
100.000000
aria_block_size
8192
aria_checkpoint_interval
30
aria_checkpoint_log_activity
1048576
aria_encrypt_tables
OFF
aria_force_start_after_recovery_failures
0
aria_group_commit
none
aria_group_commit_interval
0
aria_log_file_size
1073741824
aria_log_purge_type
immediate
aria_max_sort_file_size
9223372036853727232
aria_page_checksum
ON
aria_pagecache_age_threshold
300
aria_pagecache_buffer_size
134217728
aria_pagecache_division_limit
100
aria_pagecache_file_hash_size
512
aria_recover_options
BACKUP,QUICK
aria_repair_threads
1
aria_sort_buffer_size
268434432
aria_stats_method
nulls_unequal
aria_sync_log_dir
NEWFILE
aria_used_for_temp_tables
ON
auto_increment_increment
1
auto_increment_offset
1
autocommit
ON
automatic_sp_privileges
ON
back_log
90
basedir
/usr/
big_tables
OFF
bind_address
binlog_annotate_row_events
ON
binlog_cache_size
32768
binlog_checksum
CRC32
binlog_commit_wait_count
0
binlog_commit_wait_usec
100000
binlog_direct_non_transactional_updates
OFF
binlog_file_cache_size
16384
binlog_format
MIXED
binlog_optimize_thread_scheduling
ON
binlog_row_image
FULL
binlog_row_metadata
NO_LOG
binlog_stmt_cache_size
32768
bulk_insert_buffer_size
8388608
character_set_client
latin1
character_set_connection
latin1
character_set_database
latin1
character_set_filesystem
binary
character_set_results
latin1
character_set_server
latin1
character_set_system
utf8
character_sets_dir
/usr/share/mysql/charsets/
check_constraint_checks
ON
collation_connection
latin1_swedish_ci
collation_database
latin1_swedish_ci
collation_server
latin1_swedish_ci
column_compression_threshold
100
column_compression_zlib_level
6
column_compression_zlib_strategy
DEFAULT_STRATEGY
column_compression_zlib_wrap
OFF
completion_type
NO_CHAIN
concurrent_insert
AUTO
connect_timeout
10
core_file
OFF
datadir
/var/lib/mysql/
date_format
%Y-%m-%d
datetime_format
%Y-%m-%d %H:%i:%s
deadlock_search_depth_long
15
deadlock_search_depth_short
4
deadlock_timeout_long
50000000
deadlock_timeout_short
10000
debug_no_thread_alarm
OFF
default_password_lifetime
0
default_regex_flags
default_storage_engine
InnoDB
default_tmp_storage_engine
default_week_format
0
delay_key_write
ON
delayed_insert_limit
100
delayed_insert_timeout
300
delayed_queue_size
1000
disconnect_on_expired_password
OFF
div_precision_increment
4
encrypt_binlog
OFF
encrypt_tmp_disk_tables
OFF
encrypt_tmp_files
OFF
enforce_storage_engine
eq_range_index_dive_limit
200
event_scheduler
OFF
expensive_subquery_limit
100
expire_logs_days
0
explicit_defaults_for_timestamp
OFF
extra_max_connections
1
extra_port
0
flush
OFF
flush_time
0
foreign_key_checks
ON
ft_boolean_syntax
+ -><()~*:""&|
ft_max_word_len
84
ft_min_word_len
4
Variable_name
Value
ft_query_expansion_limit
20
ft_stopword_file
(built-in)
general_log
OFF
general_log_file
servername.log
group_concat_max_len
1048576
gtid_binlog_pos
gtid_binlog_state
gtid_cleanup_batch_size
64
gtid_current_pos
gtid_domain_id
0
gtid_ignore_duplicates
OFF
gtid_pos_auto_engines
gtid_slave_pos
gtid_strict_mode
OFF
have_compress
YES
have_crypt
YES
have_dynamic_loading
YES
have_geometry
YES
have_openssl
YES
have_profiling
YES
have_query_cache
YES
have_rtree_keys
YES
have_ssl
DISABLED
have_symlink
YES
histogram_size
254
histogram_type
DOUBLE_PREC_HB
host_cache_size
328
hostname
hostname
idle_readonly_transaction_timeout
0
idle_transaction_timeout
0
idle_write_transaction_timeout
0
ignore_builtin_innodb
OFF
ignore_db_dirs
in_predicate_conversion_threshold
1000
init_connect
init_file
init_slave
innodb_adaptive_flushing
ON
innodb_adaptive_flushing_lwm
10.000000
innodb_adaptive_hash_index
OFF
innodb_adaptive_hash_index_parts
8
innodb_adaptive_max_sleep_delay
0
innodb_autoextend_increment
64
innodb_autoinc_lock_mode
1
innodb_background_scrub_data_check_interval
0
innodb_background_scrub_data_compressed
OFF
innodb_background_scrub_data_interval
0
innodb_background_scrub_data_uncompressed
OFF
innodb_buf_dump_status_frequency
0
innodb_buffer_pool_chunk_size
134217728
innodb_buffer_pool_dump_at_shutdown
ON
innodb_buffer_pool_dump_now
OFF
innodb_buffer_pool_dump_pct
25
innodb_buffer_pool_filename
ib_buffer_pool
innodb_buffer_pool_instances
1
innodb_buffer_pool_load_abort
OFF
innodb_buffer_pool_load_at_startup
ON
innodb_buffer_pool_load_now
OFF
innodb_buffer_pool_size
16106127360
innodb_change_buffer_max_size
25
innodb_change_buffering
all
innodb_checksum_algorithm
full_crc32
innodb_cmp_per_index_enabled
OFF
innodb_commit_concurrency
0
innodb_compression_algorithm
zlib
innodb_compression_default
OFF
innodb_compression_failure_threshold_pct
5
innodb_compression_level
6
innodb_compression_pad_pct_max
50
innodb_concurrency_tickets
0
innodb_data_file_path
ibdata1:12M:autoextend
innodb_data_home_dir
innodb_deadlock_detect
ON
innodb_default_encryption_key_id
1
innodb_default_row_format
dynamic
innodb_defragment
OFF
innodb_defragment_fill_factor
0.900000
innodb_defragment_fill_factor_n_recs
20
innodb_defragment_frequency
40
innodb_defragment_n_pages
7
innodb_defragment_stats_accuracy
0
innodb_disable_sort_file_cache
OFF
innodb_disallow_writes
OFF
innodb_doublewrite
ON
innodb_encrypt_log
OFF
innodb_encrypt_tables
OFF
innodb_encrypt_temporary_tables
OFF
innodb_encryption_rotate_key_age
1
innodb_encryption_rotation_iops
100
innodb_encryption_threads
0
innodb_fast_shutdown
1
innodb_fatal_semaphore_wait_threshold
600
innodb_file_format
innodb_file_per_table
ON
innodb_fill_factor
100
innodb_flush_log_at_timeout
1
innodb_flush_log_at_trx_commit
1
innodb_flush_method
fsync
innodb_flush_neighbors
1
innodb_flush_sync
ON
Variable_name
Value
innodb_flushing_avg_loops
30
innodb_force_load_corrupted
OFF
innodb_force_primary_key
OFF
innodb_force_recovery
0
innodb_ft_aux_table
innodb_ft_cache_size
8000000
innodb_ft_enable_diag_print
OFF
innodb_ft_enable_stopword
ON
innodb_ft_max_token_size
84
innodb_ft_min_token_size
3
innodb_ft_num_word_optimize
2000
innodb_ft_result_cache_limit
2000000000
innodb_ft_server_stopword_table
innodb_ft_sort_pll_degree
2
innodb_ft_total_cache_size
640000000
innodb_ft_user_stopword_table
innodb_immediate_scrub_data_uncompressed
OFF
innodb_instant_alter_column_allowed
add_drop_reorder
innodb_io_capacity
200
innodb_io_capacity_max
2000
innodb_large_prefix
innodb_lock_schedule_algorithm
fcfs
innodb_lock_wait_timeout
50
innodb_log_buffer_size
16777216
innodb_log_checksums
ON
innodb_log_compressed_pages
ON
innodb_log_file_size
100663296
innodb_log_files_in_group
1
innodb_log_group_home_dir
./
innodb_log_optimize_ddl
OFF
innodb_log_write_ahead_size
8192
innodb_lru_flush_size
32
innodb_lru_scan_depth
1536
innodb_max_dirty_pages_pct
90.000000
innodb_max_dirty_pages_pct_lwm
0.000000
innodb_max_purge_lag
0
innodb_max_purge_lag_delay
0
innodb_max_purge_lag_wait
4294967295
innodb_max_undo_log_size
10485760
innodb_monitor_disable
innodb_monitor_enable
innodb_monitor_reset
innodb_monitor_reset_all
innodb_old_blocks_pct
37
innodb_old_blocks_time
1000
innodb_online_alter_log_max_size
134217728
innodb_open_files
36885
innodb_optimize_fulltext_only
OFF
innodb_page_cleaners
1
innodb_page_size
16384
innodb_prefix_index_cluster_optimization
OFF
innodb_print_all_deadlocks
OFF
innodb_purge_batch_size
300
innodb_purge_rseg_truncate_frequency
128
innodb_purge_threads
4
innodb_random_read_ahead
OFF
innodb_read_ahead_threshold
56
innodb_read_io_threads
4
innodb_read_only
OFF
innodb_replication_delay
0
innodb_rollback_on_timeout
OFF
innodb_scrub_log
OFF
innodb_scrub_log_speed
256
innodb_sort_buffer_size
1048576
innodb_spin_wait_delay
4
innodb_stats_auto_recalc
ON
innodb_stats_include_delete_marked
OFF
innodb_stats_method
nulls_equal
innodb_stats_modified_counter
0
innodb_stats_on_metadata
OFF
innodb_stats_persistent
ON
innodb_stats_persistent_sample_pages
20
innodb_stats_traditional
ON
innodb_stats_transient_sample_pages
8
innodb_status_output
OFF
innodb_status_output_locks
OFF
innodb_strict_mode
ON
innodb_sync_array_size
1
innodb_sync_spin_loops
30
innodb_table_locks
ON
innodb_temp_data_file_path
ibtmp1:12M:autoextend
innodb_thread_concurrency
0
innodb_thread_sleep_delay
0
innodb_tmpdir
innodb_undo_directory
./
innodb_undo_log_truncate
OFF
innodb_undo_logs
128
innodb_undo_tablespaces
0
innodb_use_atomic_writes
ON
innodb_use_native_aio
ON
innodb_version
10.5.13
innodb_write_io_threads
4
interactive_timeout
28800
join_buffer_size
3145728
join_buffer_space_limit
2097152
join_cache_level
2
keep_files_on_create
OFF
key_buffer_size
134217728
key_cache_age_threshold
300
key_cache_block_size
1024
Variable_name
Value
key_cache_division_limit
100
key_cache_file_hash_size
512
key_cache_segments
0
large_files_support
ON
large_page_size
0
large_pages
OFF
lc_messages
en_US
lc_messages_dir
lc_time_names
en_US
license
GPL
local_infile
ON
lock_wait_timeout
86400
locked_in_memory
OFF
log_bin
OFF
log_bin_basename
log_bin_compress
OFF
log_bin_compress_min_len
256
log_bin_index
log_bin_trust_function_creators
OFF
log_disabled_statements
sp
log_error
/var/lib/mysql/hostname.err
log_output
FILE
log_queries_not_using_indexes
OFF
log_slave_updates
OFF
log_slow_admin_statements
ON
log_slow_disabled_statements
sp
log_slow_filter
admin,filesort,filesort_on_disk,filesort_priority_...
log_slow_rate_limit
1
log_slow_slave_statements
ON
log_slow_verbosity
log_tc_size
24576
log_warnings
2
long_query_time
10.000000
low_priority_updates
OFF
lower_case_file_system
OFF
lower_case_table_names
0
master_verify_checksum
OFF
max_allowed_packet
268435456
max_binlog_cache_size
18446744073709547520
max_binlog_size
1073741824
max_binlog_stmt_cache_size
18446744073709547520
max_connect_errors
100
max_connections
200
max_delayed_threads
20
max_digest_length
1024
max_error_count
64
max_heap_table_size
134217728
max_insert_delayed_threads
20
max_join_size
18446744073709551615
max_length_for_sort_data
1024
max_password_errors
4294967295
max_prepared_stmt_count
16382
max_recursive_iterations
4294967295
max_relay_log_size
1073741824
max_rowid_filter_size
131072
max_seeks_for_key
4294967295
max_session_mem_used
9223372036854775807
max_sort_length
1024
max_sp_recursion_depth
0
max_statement_time
0.000000
max_tmp_tables
32
max_user_connections
0
max_write_lock_count
4294967295
metadata_locks_cache_size
1024
metadata_locks_hash_instances
8
min_examined_row_limit
0
mrr_buffer_size
262144
myisam_block_size
1024
myisam_data_pointer_size
6
myisam_max_sort_file_size
9223372036853727232
myisam_mmap_size
18446744073709551615
myisam_recover_options
BACKUP,QUICK
myisam_repair_threads
1
myisam_sort_buffer_size
134216704
myisam_stats_method
NULLS_UNEQUAL
myisam_use_mmap
OFF
mysql56_temporal_format
ON
net_buffer_length
16384
net_read_timeout
30
net_retry_count
10
net_write_timeout
60
old
OFF
old_alter_table
DEFAULT
old_mode
old_passwords
OFF
open_files_limit
74000
optimizer_max_sel_arg_weight
32000
optimizer_prune_level
1
optimizer_search_depth
62
optimizer_selectivity_sampling_limit
100
optimizer_switch
index_merge=on,index_merge_union=on,index_merge_so...
optimizer_trace
enabled=off
optimizer_trace_max_mem_size
1048576
optimizer_use_condition_selectivity
4
performance_schema
OFF
performance_schema_accounts_size
-1
performance_schema_digests_size
-1
performance_schema_events_stages_history_long_size
-1
performance_schema_events_stages_history_size
-1
performance_schema_events_statements_history_long_...
-1
Variable_name
Value
performance_schema_events_statements_history_size
-1
performance_schema_events_transactions_history_lon...
-1
performance_schema_events_transactions_history_siz...
-1
performance_schema_events_waits_history_long_size
-1
performance_schema_events_waits_history_size
-1
performance_schema_hosts_size
-1
performance_schema_max_cond_classes
90
performance_schema_max_cond_instances
-1
performance_schema_max_digest_length
1024
performance_schema_max_file_classes
80
performance_schema_max_file_handles
32768
performance_schema_max_file_instances
-1
performance_schema_max_index_stat
-1
performance_schema_max_memory_classes
320
performance_schema_max_metadata_locks
-1
performance_schema_max_mutex_classes
210
performance_schema_max_mutex_instances
-1
performance_schema_max_prepared_statements_instanc...
-1
performance_schema_max_program_instances
-1
performance_schema_max_rwlock_classes
50
performance_schema_max_rwlock_instances
-1
performance_schema_max_socket_classes
10
performance_schema_max_socket_instances
-1
performance_schema_max_sql_text_length
1024
performance_schema_max_stage_classes
160
performance_schema_max_statement_classes
222
performance_schema_max_statement_stack
10
performance_schema_max_table_handles
-1
performance_schema_max_table_instances
-1
performance_schema_max_table_lock_stat
-1
performance_schema_max_thread_classes
50
performance_schema_max_thread_instances
-1
performance_schema_session_connect_attrs_size
-1
performance_schema_setup_actors_size
-1
performance_schema_setup_objects_size
-1
performance_schema_users_size
-1
pid_file
/var/lib/mysql/servername.pid
plugin_dir
/usr/lib64/mysql/plugin/
plugin_maturity
gamma
port
3306
preload_buffer_size
32768
profiling
OFF
profiling_history_size
15
progress_report_time
5
protocol_version
10
proxy_protocol_networks
query_alloc_block_size
16384
query_cache_limit
1048576
query_cache_min_res_unit
4096
query_cache_size
1048576
query_cache_strip_comments
OFF
query_cache_type
OFF
query_cache_wlock_invalidate
OFF
query_prealloc_size
24576
range_alloc_block_size
4096
read_binlog_speed_limit
0
read_buffer_size
4194304
read_only
OFF
read_rnd_buffer_size
524288
relay_log
relay_log_basename
relay_log_index
relay_log_info_file
relay-log.info
relay_log_purge
ON
relay_log_recovery
OFF
relay_log_space_limit
0
replicate_annotate_row_events
ON
replicate_do_db
replicate_do_table
replicate_events_marked_for_skip
REPLICATE
replicate_ignore_db
replicate_ignore_table
replicate_wild_do_table
replicate_wild_ignore_table
report_host
report_password
report_port
3306
report_user
require_secure_transport
OFF
rowid_merge_buff_size
8388608
rpl_semi_sync_master_enabled
OFF
rpl_semi_sync_master_timeout
10000
rpl_semi_sync_master_trace_level
32
rpl_semi_sync_master_wait_no_slave
ON
rpl_semi_sync_master_wait_point
AFTER_COMMIT
rpl_semi_sync_slave_delay_master
OFF
rpl_semi_sync_slave_enabled
OFF
rpl_semi_sync_slave_kill_conn_timeout
5
rpl_semi_sync_slave_trace_level
32
secure_auth
ON
secure_file_priv
secure_timestamp
NO
server_id
1
session_track_schema
ON
session_track_state_change
OFF
session_track_system_variables
autocommit,character_set_client,character_set_conn...
session_track_transaction_info
OFF
skip_external_locking
ON
skip_name_resolve
OFF
skip_networking
OFF
Variable_name
Value
skip_show_database
OFF
slave_compressed_protocol
OFF
slave_ddl_exec_mode
IDEMPOTENT
slave_domain_parallel_threads
0
slave_exec_mode
STRICT
slave_load_tmpdir
/tmp
slave_max_allowed_packet
1073741824
slave_net_timeout
60
slave_parallel_max_queued
131072
slave_parallel_mode
optimistic
slave_parallel_threads
0
slave_parallel_workers
0
slave_run_triggers_for_rbr
NO
slave_skip_errors
OFF
slave_sql_verify_checksum
ON
slave_transaction_retries
10
slave_transaction_retry_errors
1158,1159,1160,1161,1205,1213,1429,2013,12701
slave_transaction_retry_interval
0
slave_type_conversions
slow_launch_time
2
slow_query_log
OFF
slow_query_log_file
servername-slow.log
socket
/var/lib/mysql/mysql.sock
sort_buffer_size
1048576
sql_auto_is_null
OFF
sql_big_selects
ON
sql_buffer_result
OFF
sql_if_exists
OFF
sql_log_bin
ON
sql_log_off
OFF
sql_mode
STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_...
sql_notes
ON
sql_quote_show_create
ON
sql_safe_updates
OFF
sql_select_limit
18446744073709551615
sql_slave_skip_counter
0
sql_warnings
OFF
ssl_ca
ssl_capath
ssl_cert
ssl_cipher
ssl_crl
ssl_crlpath
ssl_key
standard_compliant_cte
ON
storage_engine
InnoDB
stored_program_cache
256
strict_password_validation
ON
sync_binlog
0
sync_frm
ON
sync_master_info
10000
sync_relay_log
10000
sync_relay_log_info
10000
system_time_zone
IST
system_versioning_alter_history
ERROR
system_versioning_asof
DEFAULT
table_definition_cache
37000
table_open_cache
36885
table_open_cache_instances
1
tcp_keepalive_interval
0
tcp_keepalive_probes
0
tcp_keepalive_time
0
tcp_nodelay
ON
thread_cache_size
200
thread_handling
one-thread-per-connection
thread_pool_dedicated_listener
OFF
thread_pool_exact_stats
OFF
thread_pool_idle_timeout
60
thread_pool_max_threads
65536
thread_pool_oversubscribe
3
thread_pool_prio_kickup_timer
1000
thread_pool_priority
auto
thread_pool_size
36
thread_pool_stall_limit
500
thread_stack
299008
time_format
%H:%i:%s
time_zone
SYSTEM
tls_version
TLSv1.1,TLSv1.2,TLSv1.3
tmp_disk_table_size
18446744073709551615
tmp_memory_table_size
134217728
tmp_table_size
134217728
tmpdir
/tmp
Couldn't paste full global prams as stack limit but thats around 95% of it.
We have disabled swap in the previous my.cnf edit, as for mariadb even when there are alot of free memory within the system is still building swap until swap reached 100%(4GB of swap).
very strange behaviour
I cannot create a directory
[root#XXXXXX DEV]# mkdir 1
mkdir: cannot create directory `1': No space left on device
[root#dev-albert DEV]# pwd
/deployment/.octopus/Applications/OctopusServer/DEV
[root#XXXXXX DEV]# df -P /deployment
Filesystem 1024-blocks Used Available Capacity Mounted on
/dev/mapper/deploymentvg-deployment 10321208 5229888 4567096 54%
/deployment
[root#dev-albert DEV]# df -Pi /deployment
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/mapper/deploymentvg-deployment 655360 69129 586231 11%
/deployment
As you can see, plenty of space , good number of inodes free.
Does anyone have any clue what is happening with my system.
[root#dev-albert DEV]# dmsetup ls
rootvg-tmp (252:6)
rootvg-usr (252:7)
rootvg-var (252:8)
deploymentvg-usropenv (252:3)
deploymentvg-deployment (252:2)
rootvg-agent (252:4)
rootvg-oracle (252:11)
rootvg-varlock (252:9)
rootvg-deployment (252:5)
rootvg-swap (252:1)
rootvg-root (252:0)
rootvg-varspool (252:10)
top output
top - 14:44:35 up 347 days, 20:40, 2 users, load average: 2.02, 2.02, 2.05
Tasks: 125 total, 2 running, 123 sleeping, 0 stopped, 0 zombie
Cpu(s):100.0%us, 0.0%sy, 0.0%ni,117100.0%id,-42916200.0%wa, 0.0%hi,
0.0%si,200.0%st
Mem: 4071932k total, 3394132k used, 677800k free, 780312k buffers
Swap: 4194300k total, 22604k used, 4171696k free, 1742552k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
747 root 20 0 0 0 0 S 3.0 0.0 303:33.05 jbd2/dm-2-8
20679 root 20 0 0 0 0 S 2.7 0.0 0:14.24 kworker/0:2
16319 root 20 0 0 0 0 R 2.3 0.0 266:30.45 flush-252:2
When I run mkdir with strace
open("/usr/lib/locale/locale-archive", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=99158576, ...}) = 0
mmap(NULL, 99158576, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fd4c4b04000
close(3) = 0
mkdir("1", 0777) = -1 ENOSPC (No space left on
device)
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
write(2, ": No space left on device", 25: No space left on device) = 25
uname output
Linux 2.6.39-400.17.1.el6uek.x86_64 #1 SMP Fri Feb 22 18:16:18 PST 2013 x86_64 x86_64 x86_64 GNU/Linux
Sometimes that can be caused by the b-tree used by ext4 as directory index hitting its height limit. If you get the No space left on device error on mkdir for some names but not others, or there's plenty of space and inodes, check your dmesg for these warnings:
EXT4-fs warning (device dm-0): ext4_dx_add_entry:2226: Directory (ino: 80087286) index full, reach max htree level :2
EXT4-fs warning (device dm-0): ext4_dx_add_entry:2230: Large directory feature is not enabled on this filesystem
That means you're hitting the b-tree limit, and on a pinch you can enable large directory with:
tune2fs -O large_dir <dev>
It doesn't require unounting or rebooting, and it will increase the limit from 10M to 2B. Depending on what you're doing you're likely to hit performance bottlenecks or actually filling the disk before hitting the limit again, but I recommend rethinking your directory structure to avoid creating too many files and subdirectories in the same directory, and use the above solution only in an emergency.
I'm running the following simple script:
create table MyTable (filler char(10))
go
insert into MyTable (filler) values ('a')
go 1
exec sp_spaceused MyTable
go
drop table MyTable
go
and get the following result:
rows reserved data index_size unused
------ ---------- ------ ----------- -------
1 72 KB 8 KB 8 KB 56 KB
My questions:
Why 72 KB were reserved?
Why index_size is 8 KB if the table is not even indexed?
EDIT:
I'd like to add a follow-up:
When changing the script a little:
create table MyTable (filler char(69))
go
insert into MyTable (filler) values ('a')
go 100
I get:
rows reserved data index_size unused
------ ---------- ------ ----------- -------
100 72 KB 16 KB 8 KB 48 KB
Note that defining filler's size to 68 bytes (and inserting 100 rows) still gives 8KB as the data value (we can continue and set it to 148 bytes, which will result in another 8KB increment, i.e. to 24KB).
Can you help me break down the calculation? If (apparently) only 6,900 bytes are used, What is the cause for the 8KB addition?
EDIT #2:
Here's the results of DBCC PAGE:
PAGE: (1:4392)
BUFFER:
BUF #0x00000000061A78C0
bpage = 0x00000001EF3A8000 bhash = 0x0000000000000000 bpageno = (1:4392)
bdbid = 6 breferences = 0 bcputicks = 0
bsampleCount = 0 bUse1 = 18482 bstat = 0x9
blog = 0x15ab215a bnext = 0x0000000000000000 bDirtyContext = 0x0000000000000000
bstat2 = 0x0
PAGE HEADER:
Page #0x00000001EF3A8000
m_pageId = (1:4392) m_headerVersion = 1 m_type = 1
m_typeFlagBits = 0x0 m_level = 0 m_flagBits = 0x8200
m_objId (AllocUnitId.idObj) = 260 m_indexId (AllocUnitId.idInd) = 256
Metadata: AllocUnitId = 72057594054967296
Metadata: PartitionId = 72057594048151552 Metadata: IndexId = 0
Metadata: ObjectId = 1698105090 m_prevPage = (0:0) m_nextPage = (0:0)
pminlen = 72 m_slotCnt = 100 m_freeCnt = 396
m_freeData = 7596 m_reservedCnt = 0 m_lsn = (55:8224:2)
m_xactReserved = 0 m_xdesId = (0:0) m_ghostRecCnt = 0
m_tornBits = -2116084714 DB Frag ID = 1
Allocation Status
GAM (1:2) = ALLOCATED SGAM (1:3) = NOT ALLOCATED PFS (1:1) = 0x44 ALLOCATED 100_PCT_FULL
DIFF (1:6) = CHANGED ML (1:7) = NOT MIN_LOGGED
Slot 0 Offset 0x60 Length 75
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP Record Size = 75
Memory Dump #0x0000000012A3A060
0000000000000000: 10004800 61202020 20202020 20202020 20202020 ..H.a
0000000000000014: 20202020 20202020 20202020 20202020 20202020
0000000000000028: 20202020 20202020 20202020 20202020 20202020
000000000000003C: 20202020 20202020 20202020 010000 ...
Slot 0 Column 1 Offset 0x4 Length 68 Length (physical) 68
filler = a
-- NOTE: The structure of each Slot is identical to that of Slot #0, so we can simply jump to slot 99:
Slot 99 Offset 0x1d61 Length 75
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP Record Size = 75
Memory Dump #0x0000000012A3BD61
0000000000000000: 10004800 61202020 20202020 20202020 20202020 ..H.a
0000000000000014: 20202020 20202020 20202020 20202020 20202020
0000000000000028: 20202020 20202020 20202020 20202020 20202020
000000000000003C: 20202020 20202020 20202020 010000 ...
Slot 99 Column 1 Offset 0x4 Length 68 Length (physical) 68
filler = a
So we can see the last slot starts after 7521 bytes, and adding its size gives us 7,596 bytes. If we add the size of the slot array (in which each pointer is 2 bytes), we get 7,796 bytes.
However, we need to get to 8,192 bytes to fill the page. What's missing?
The 72K of reserved space includes a 64K extent (8 pages of 8K each) plus the 8K IAM page overhead. Of this 72K, only the IAM page and a single data page is actually used. sp_space_used reports the IAM page in the index_size, albeit not technically an index. You can see these details with the undocumented sys.dm_db_database_page_allocations TVF (use only on a test system):
SELECT extent_file_id, extent_page_id, page_type_desc
FROM sys.dm_db_database_page_allocations(DB_ID(), OBJECT_ID(N'dbo.MyTable'), 0, 1, 'DETAILED');
This database apparently has the MIXED_PAGE_ALLOCATION database option set to OFF so a full 64K extent is allocated a initially. If the option were ON, the single data page would be allocated from a mixed extent instead of a 64K extent dedicated to the table. The space allocated in that case would be 16K - a 8K single data page plus the IAM page.
Although mixed extents do reduce space requirements for small tables (under 64K), mixed extents have more overhead and can cause allocation contention in a high concurrency workload so it is off by default in SQL 2016 onwards. In older SQL versions, mixed extent allocation was on by default and can be turned off at the server level with trace flag 1118.
You can see the mixed extent setting in sys.databases:
SELECT name, is_mixed_page_allocation_on
FROM sys.databases;
To toggle the setting:
ALTER DATABASE Test
SET MIXED_PAGE_ALLOCATION ON;
EDIT 1:
Space within a data page includes overhead for the page itself as well as records within the page. This overhead, plus the space needed for user data, will determine how many rows can fit on a page and number of data pages required to store a given number of rows. See Paul Randal's anatomy of a page and anatomy of a record articles for details of that overhead.
EDIT 2:
From your follow-up comment:
7998 bytes, so there are more 194 bytes to go for the next allocation.
What am I missing?
I almost never use heaps but as you can see in the page dump, the associated PFS (page free space) allocation status for this page is 100 percent full. According to Kalen Delaney's Microsoft SQL Server 2012 Internals book, the PFS status is actually a 3-bit mask of these ranges:
000: empty
001: 1-50% full
010: 51-80% full
011: 81-95% full
100: 96-100% full
So it looks like once heap page fullness crossed the 96% percent threshold it was considered 100% full and a new page was allocated. Note this does not happen on a table with a clustered index because the page for a new row is first determined by the CI key and a new page allocated only if it can't fit in that page at all. Yet another reason to avoid heaps.
We have a project written in ANSI C. Generally the memory consumption was not a big concern, but now we have a request to fit our program into 256 KB of RAM. I don't have this exact platform on hands, so I compile my project under 32 bit x86 Linux (because it provides enough different tools to evaluate the memory consumption), optimize what I can, remove some features and eventually I have to have the conclusion: what features we need to sacrifice to be able to run on very small systems (if we're able at all). First of all I did a research what exactly a memory size in linux and it seems I have to optimize the RSS size, not VSZ. But in linux even a smallest program which prints "Hello world!" once a second consumes 285-320 KB in RSS:
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
unsigned char cuStopCycle = 0;
void SigIntHandler(int signo)
{
printf("SIGINT received, terminating the program\n");
cuStopCycle = 1;
}
int main()
{
signal( SIGINT, SigIntHandler);
while(!cuStopCycle)
{
printf("Hello, World!\n");
sleep(1);
}
printf("Exiting...\n");
}
user#Ubuntu12-vm:~/tmp/prog_size$ size ./prog_size
text data bss dec hex filename
1456 272 12 1740 6cc ./prog_size
root#Ubuntu12-vm:/home/app# ps -C prog_size -o pid,rss,vsz,args
PID RSS VSZ COMMAND
22348 316 2120 ./prog_size
Obviously this program will perfectly run on small PLCs, with 64KB of RAM. It is just linux loads a lot of libs. I generate a map file for this program and all this data + bss comes from the CRT library. I need to mention that if I add some code to this project - 10,000 times "a = a + b" or manipulate arrays 2000 long int variables, I see the difference in code size, bss size but eventually the RSS size of the process is the same, it doesn't affected)
So I take this as a baseline, the point I want to reach (and which I will never reach, because I need more functions than just print a message once a second).
So here comes my project, where I removed all extra features, removed all auxiliary functions, removed everything except the basic functionality. There are some ways to optimize more, but not that much, what could be removed is already taken away:
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt/Cmds# ls -l App
-rwxr-xr-x 1 root root 42520 Jul 13 18:33 App
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt/Cmds# size ./App
text data bss dec hex filename
37027 404 736 38167 9517 ./App
So I have ~36KB of code and ~1KB of data. I do not call malloc inside of my project, I use a shared memory allocation with a wrapper library so I can control how much memory is allocated:
The total memory size allocated is 2052 bytes
Under the hood there are malloc calls obviously, if I substitute 'malloc' calls with my function which summarize all alloc requests I see that ~2.3KB of memory is allocated:
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt/Cmds# LD_PRELOAD=./override_malloc.so ./App
Malloc allocates 2464 bytes total
Now I run my project amd see that it consumes 600KB of RAM.
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt# ps -C App -o pid,rss,vsz,args
PID RSS VSZ COMMAND
22093 604 2340 ./App
I do not understand why it eats so much memory. The code size is small. There is not much memory allocated. The size of data is small. Why it takes so much memory? I tried to analyze the mapping of the process:
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt# pmap -x 22093
22093: ./App
Address Kbytes RSS Dirty Mode Mapping
08048000 0 28 0 r-x-- App
08052000 0 4 4 r---- App
08053000 0 4 4 rw--- App
09e6a000 0 4 4 rw--- [ anon ]
b7553000 0 4 4 rw--- [ anon ]
b7554000 0 48 0 r-x-- libpthread-2.15.so
b756b000 0 4 4 r---- libpthread-2.15.so
b756c000 0 4 4 rw--- libpthread-2.15.so
b756d000 0 8 8 rw--- [ anon ]
b7570000 0 300 0 r-x-- libc-2.15.so
b7714000 0 8 8 r---- libc-2.15.so
b7716000 0 4 4 rw--- libc-2.15.so
b7717000 0 12 12 rw--- [ anon ]
b771a000 0 16 0 r-x-- librt-2.15.so
b7721000 0 4 4 r---- librt-2.15.so
b7722000 0 4 4 rw--- librt-2.15.so
b7731000 0 4 4 rw-s- [ shmid=0x70000c ]
b7732000 0 4 4 rw-s- [ shmid=0x6f800b ]
b7733000 0 4 4 rw-s- [ shmid=0x6f000a ]
b7734000 0 4 4 rw-s- [ shmid=0x6e8009 ]
b7735000 0 12 12 rw--- [ anon ]
b7738000 0 4 0 r-x-- [ anon ]
b7739000 0 104 0 r-x-- ld-2.15.so
b7759000 0 4 4 r---- ld-2.15.so
b775a000 0 4 4 rw--- ld-2.15.so
bfb41000 0 12 12 rw--- [ stack ]
-------- ------- ------- ------- -------
total kB 2336 - - -
And it looks like the program size (in RSS) is only 28KB, the rest is consumed by shared libraries. BTW I do not use posix threads, I do not explicitly link to it, but somehow the linker anyway links this library I have no idea why (this is not really important). If we look at the mapping in more details:
root#Ubuntu12-vm:/home/app/workspace/proj_sizeopt# cat /proc/22093/smaps
08048000-08052000 r-xp 00000000 08:01 344838 /home/app/workspace/proj_sizeopt/Cmds/App
Size: 40 kB
Rss: 28 kB
Pss: 28 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 28 kB
Private_Dirty: 0 kB
Referenced: 28 kB
Anonymous: 0 kB
AnonHugePages: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
...
09e6a000-09e8b000 rw-p 00000000 00:00 0 [heap]
Size: 132 kB
Rss: 4 kB
Pss: 4 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 4 kB
Referenced: 4 kB
Anonymous: 4 kB
AnonHugePages: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
...
b7570000-b7714000 r-xp 00000000 08:01 34450 /lib/i386-linux-gnu/libc-2.15.so
Size: 1680 kB
Rss: 300 kB
Pss: 7 kB
Shared_Clean: 300 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 300 kB
Anonymous: 0 kB
AnonHugePages: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
...
b7739000-b7759000 r-xp 00000000 08:01 33401 /lib/i386-linux-gnu/ld-2.15.so
Size: 128 kB
Rss: 104 kB
Pss: 3 kB
Shared_Clean: 104 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 104 kB
Anonymous: 0 kB
AnonHugePages: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
...
bfb41000-bfb62000 rw-p 00000000 00:00 0 [stack]
Size: 136 kB
Rss: 12 kB
Pss: 12 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 12 kB
Referenced: 12 kB
Anonymous: 12 kB
AnonHugePages: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
So I see that RSS size for my project is 40KB, but only 28 KB is used. Does it mean that this project will fit into 256 KB of RAM?
The heap size is 132KB but only 4 KB is used. Why is that? I'm sure it will be different on the small embedded platform.
The stack is 136KB but only 12KB is used.
GLIBC/LD obviously consume some memory, but what exactly memory will it be on the embedded platform?
I do not look at PSS because it doesn't make any sense in my case, I look only at RSS.
What conclusions can I draw from this picture? How exactly to evaluate memory consumption by the application? Look at the RSS size of the process? Or subtract from this size RSS of all mapped system libraries? What is about heap/stack size?
I would be very grateful for any advises, notes, memory consumption optimizations techniques, DOs and DON'Ts for platforms with extremely small amount of RAM (except obvious - keep amount of data and code to the very minimum).
I also will appreciate an explanation WHY the program with small amount of code and data (and which doesn't allocate much memory) still consumes a lot of RAM in RSS.
Thank you in advance
... fit our program into 256 KB of RAM. I don't have this exact platform on hands, so I compile my project under 32 bit x86 Linux..
And what you now see is that the Linux platform tools make reasonable assumptions of your possible need of stack and heap, given that it nows you run on a big machine, and links-in a reasonable set of library functions for your needs. Some you won't need, but it gives them to you "for free".
To fit in 256 Kb on your target platform, you must compile for your target platform and link with the target platform's libraries (and CRT) using the target platform's linker.
Those will make different assumptions, use possibly smaller linbrary footprints, make smaller assumptions on stack and heap space, etcetera. For example, create "Hello World" for the target platform and check its needs on that target platform. Or use a realistic simulator of the target platform and libraries (and not to forget, OS, whch partly dictates what the libraries must do).
And if it is then still too big, you have to re-write or tweak the whole CRT and all libraries....
the program needs to be compiled/linked with the embedded device in mind.
For best results use a makefile
use the 'rt' library written for the embedded device
use the start.s file, located, via the makefile, where execution begins.
use 'static' in the linker parameters
use the linker parameters to not include any libraries but what is specifically requested.
do not use libraries written for your development machine. Only use libraries written for the embedded device.
do NOT include stdio.h, etc. unless specifically written for the embedded device
do NOT call printf() inside a signal handler.
if possible, do not call printf() at all.
instead write a small char output function and have it perform the output through the uart.
do not use signals, instead use interrupts
the resulting application will not run on your PC., but, once loaded, will run on the 256k device
do not call sleep(), rather write your own function that uses a device timer peripheral, that sets the timer and puts the device into powerdown mode.
the time interrupt needs to bring the device out of the powerdown mode.
in the makefile, specifically set the size of the stack, heap, etc.
have the link step output a .map file. study that map file until you understand everything in it.
use a compiler/linker that is specific for the embedded device
you probably will need to include a function that initializes the peripherals on the device, like the clock, the uart, the timer, the watchdog, and any other built in peripherals that the code actually uses.
you will need a file that allocates the interrupt table, and a small function to handle each of the interrupts, even though most of those functions will do nothing beyond clearing the appropriate interrupt pending flag and returning from the interrupt
you will probably need a function to periodically refresh the watchdog, conditionally, depending on an indication that the main function is still cycling regularily. I.E the main function loop and the initialization function will refresh the watchdog
I've just downloaded DrMemory and wanted to check for memory leaks in my application where I came across that DrMemory shows memory leaks on an "empty program"!
Where do those memory leaks come from?
And secondly, what is an example of what beginners often do wrong which causes DrMemory to complain about uninitialized access(es)?
Note that I am relatively new to C and all that native stuff, so I don't understand most of the things DrMemory tells me here..
int main() {
}
gcc main.c -o a.exe
drmemory -show_reachable -- a.exe
Dr. Memory version 1.4.6 build 2 built on Mar 7 2012 10:14:04
Application cmdline: ""C:\Users\niklas\Desktop\a.exe""
Recorded 62 suppression(s) from default C:\DrMemory/bin/suppress-default.txt
REACHABLE LEAK 532 direct bytes 0x003e07d0-0x003e09e4 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 1152 direct bytes 0x003e09f0-0x003e0e70 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 8 direct bytes 0x003e11a8-0x003e11b0 + 0 indirect bytes
# 0 msvcrt.dll!towlower
# 1 msvcrt.dll!towlower
# 2 msvcrt.dll!clearerr_s
# 3 msvcrt.dll!clearerr_s
# 4 __mingw_CRTStartup
# 5 mainCRTStartup
# 6 KERNEL32.dll!BaseThreadInitThunk
# 7 ntdll.dll!RtlInitializeExceptionChain
# 8 ntdll.dll!RtlInitializeExceptionChain
REACHABLE LEAK 80 direct bytes 0x003e11d8-0x003e1228 + 0 indirect bytes
# 0 __cmshared_create_or_grab [../../../../gcc-4.4.1/libgcc/../gcc/config/i386/cygming-shared-data.c:145]
# 1 __gcc_register_frame
# 2 register_frame_ctor
# 3 __do_global_ctors
# 4 __mingw_CRTStartup
# 5 mainCRTStartup
# 6 KERNEL32.dll!BaseThreadInitThunk
# 7 ntdll.dll!RtlInitializeExceptionChain
# 8 ntdll.dll!RtlInitializeExceptionChain
REACHABLE LEAK 544 direct bytes 0x003e1568-0x003e1788 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 1863 direct bytes 0x003e1790-0x003e1ed7 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 4096 direct bytes 0x003e2780-0x003e3780 + 0 indirect bytes
# 0 msvcrt.dll!strcpy_s +0x5f (0x76aff5d3 <msvcrt.dll+0xf5d3>)
# 1 msvcrt.dll!wprintf +0x142 (0x76b15f26 <msvcrt.dll+0x25f26>)
# 2 msvcrt.dll!printf +0x35 (0x76b0c5ef <msvcrt.dll+0x1c5ef>)
# 3 main
REACHABLE LEAK 24 direct bytes 0x005307d0-0x005307e8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE POSSIBLE LEAK 3526 direct bytes 0x005307f0-0x005315b6 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE POSSIBLE LEAK 2678 direct bytes 0x005315c0-0x00532036 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 60 direct bytes 0x00532040-0x0053207c + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 48 direct bytes 0x00532088-0x005320b8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 120 direct bytes 0x005320c0-0x00532138 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 120 direct bytes 0x00532140-0x005321b8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 540 direct bytes 0x005321c0-0x005323dc + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 66 direct bytes 0x005323e8-0x0053242a + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE POSSIBLE LEAK 120 direct bytes 0x00532438-0x005324b0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x005324b8-0x005324c8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 70 direct bytes 0x005324d0-0x00532516 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE POSSIBLE LEAK 120 direct bytes 0x00532520-0x00532598 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x005325b8-0x005325c8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x005325a0-0x005325b0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 66 direct bytes 0x005325d0-0x00532612 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532620-0x00532640 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 100 direct bytes 0x00532648-0x005326ac + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x005326b8-0x005326d8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 512 direct bytes 0x005326e0-0x005328e0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 512 direct bytes 0x005328e8-0x00532ae8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 36 direct bytes 0x00532af0-0x00532b14 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 36 direct bytes 0x00532b20-0x00532b44 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 48 direct bytes 0x00532b50-0x00532b80 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532b88-0x00532ba8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532bb0-0x00532bd0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532bd8-0x00532bf8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532c28-0x00532c48 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00532c50-0x00532c70 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x00532c78-0x00532c88 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 62 direct bytes 0x00532c90-0x00532cce + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 120 direct bytes 0x00532cd8-0x00532d50 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x00532d58-0x00532d68 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x00532d70-0x00532d80 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x00532d88-0x00532d98 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x00532da0-0x00532db0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 520 direct bytes 0x00532de0-0x00532fe8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 1024 direct bytes 0x00532ff0-0x005333f0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x005333f8-0x00533418 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00533420-0x00533440 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x00533448-0x00533468 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 206 direct bytes 0x005334e0-0x005335ae + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 16 direct bytes 0x005336f0-0x00533700 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 100 direct bytes 0x00533708-0x0053376c + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 120 direct bytes 0x00533778-0x005337f0 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 32 direct bytes 0x005337f8-0x00533818 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 62 direct bytes 0x00533820-0x0053385e + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 62 direct bytes 0x00533868-0x005338a6 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 36 direct bytes 0x005338d8-0x005338fc + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 24 direct bytes 0x00533908-0x00533920 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 8 direct bytes 0x00533928-0x00533930 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 1288 direct bytes 0x00533950-0x00533e58 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 888 direct bytes 0x00533e60-0x005341d8 + 0 indirect bytes
# 0 <not in a module> (0x00000000)
REACHABLE LEAK 520 direct bytes 0x00534888-0x00534a90 + 0 indirect bytes
# 0 ntdll.dll!RtlInitializeExceptionChain +0x1e8 (0x7712b57a <ntdll.dll+0x5b57a>)
# 1 KERNELBASE.dll!GetEnvironmentVariableA +0x18b (0x752e7b22 <KERNELBASE.dll+0x7b22>)
# 2 msvcrt.dll!memicmp +0x85 (0x76b0074e <msvcrt.dll+0x1074e>)
# 3 msvcrt.dll!ismbblead +0x2f (0x76aff637 <msvcrt.dll+0xf637>)
# 4 msvcrt.dll!ismbblead +0x12 (0x76aff61a <msvcrt.dll+0xf61a>)
# 5 msvcrt.dll!clearerr_s +0x3fa (0x76b09fb0 <msvcrt.dll+0x19fb0>)
# 6 msvcrt.dll!clearerr_s +0x2e3 (0x76b09e99 <msvcrt.dll+0x19e99>)
# 7 msvcrt.dll!clearerr_s +0x27e (0x76b09e34 <msvcrt.dll+0x19e34>)
# 8 __mingw_CRTStartup
# 9 mainCRTStartup
#10 KERNEL32.dll!BaseThreadInitThunk
#11 ntdll.dll!RtlInitializeExceptionChain
REACHABLE LEAK 644 direct bytes 0x00534b78-0x00534dfc + 0 indirect bytes
# 0 ntdll.dll!RtlLookupAtomInAtomTable
# 1 ntdll.dll!RtlCreateAtomTable
# 2 KERNEL32.dll!GetThreadId
# 3 KERNEL32.dll!LocalUnlock
# 4 KERNEL32.dll!FindAtomA
# 5 __cmshared_create_or_grab [../../../../gcc-4.4.1/libgcc/../gcc/config/i386/cygming-shared-data.c:140]
# 6 __gcc_register_frame
# 7 register_frame_ctor
# 8 __do_global_ctors
# 9 __mingw_CRTStartup
#10 mainCRTStartup
#11 KERNEL32.dll!BaseThreadInitThunk
REACHABLE POSSIBLE LEAK 32 direct bytes 0x00534e28-0x00534e48 + 0 indirect bytes
# 0 ntdll.dll!RtlInitializeCriticalSectionEx +0x12b (0x77127de3 <ntdll.dll+0x57de3>)
# 1 ntdll.dll!RtlInitializeCriticalSectionEx +0x82 (0x77127d3b <ntdll.dll+0x57d3b>)
# 2 ntdll.dll!RtlInitializeCriticalSection +0x11 (0x7712f8d0 <ntdll.dll+0x5f8d0>)
# 3 ntdll.dll!RtlCreateAtomTable +0x8b (0x770f8767 <ntdll.dll+0x28767>)
# 4 ntdll.dll!RtlCreateAtomTable +0x60 (0x770f873c <ntdll.dll+0x2873c>)
# 5 KERNEL32.dll!GetThreadId +0x1e (0x7726a912 <KERNEL32.dll+0x4a912>)
# 6 KERNEL32.dll!LocalUnlock +0x44 (0x772692ea <KERNEL32.dll+0x492ea>)
# 7 KERNEL32.dll!FindAtomA +0x10 (0x7725bac1 <KERNEL32.dll+0x3bac1>)
# 8 __cmshared_create_or_grab [../../../../gcc-4.4.1/libgcc/../gcc/config/i386/cygming-shared-data.c:140]
# 9 __gcc_register_frame
#10 register_frame_ctor
#11 __do_global_ctors
REACHABLE LEAK 158 direct bytes 0x00534f30-0x00534fce + 0 indirect bytes
# 0 ntdll.dll!RtlLookupAtomInAtomTable +0x1f1 (0x770f86af <ntdll.dll+0x286af>)
# 1 ntdll.dll!RtlAddAtomToAtomTable +0xbd (0x770f5e8e <ntdll.dll+0x25e8e>)
# 2 KERNEL32.dll!GetSystemDefaultLCID +0x395 (0x77269bfd <KERNEL32.dll+0x49bfd>)
# 3 KERNEL32.dll!AddAtomA +0x10 (0x77259ec9 <KERNEL32.dll+0x39ec9>)
# 4 __cmshared_create_or_grab [../../../../gcc-4.4.1/libgcc/../gcc/config/i386/cygming-shared-data.c:118]
# 5 __gcc_register_frame
# 6 register_frame_ctor
# 7 __do_global_ctors
# 8 __mingw_CRTStartup
# 9 mainCRTStartup
#10 KERNEL32.dll!BaseThreadInitThunk
#11 ntdll.dll!RtlInitializeExceptionChain
DUPLICATE ERROR COUNTS:
SUPPRESSIONS USED:
NO ERRORS FOUND:
0 unique, 0 total unaddressable access(es)
0 unique, 0 total uninitialized access(es)
0 unique, 0 total invalid heap argument(s)
0 unique, 0 total warning(s)
0 unique, 0 total, 0 byte(s) of leak(s)
0 unique, 0 total, 0 byte(s) of possible leak(s)
ERRORS IGNORED:
64 still-reachable allocation(s)
Details: C:\DrMemory/drmemory/logs/DrMemory-a.exe.7400.000/results.txt
Perhaps not Dr. Memory, but an example of how users forget to initialize data is below. I'd describe these as the canonical way that people forget to initialize data. People forget that malloc does not clear the memory area.
struct object_t {
int x;
int *y;
};
struct object_t *object = malloc(sizeof(struct object_t));
if (object->y == NULL) {
<Do stuff>
}
if (object->x == 32) {
<Do stuff>
}
The standard C library (libc) is always linked to your code and it contains special setup code which, for example, knows where/how the OS will provide command line arguments, so it can set up the string array to call main(), set up I/O buffering, connect the file descriptors to the globals stdin, stdout and stderr, etc.
This code does allocate memory but it should also release any resources, so I'm also stumped why DrMemory would report leaks there.
One theory could be that GCC optimizes the code in this special case (because the OS will clean up any such problems after your process terminates) but I doubt that. To verify it, print something to stdout - that should enable the cleanup. If the memory leaks go away, it was an optimizer glitch.
Or, since all the leaks are in native DLLs code, it's a bug by Microsoft.
Try these steps:
Install all the service packs for your OS
Report an error to DrMemory - maybe they know more
Try to compile more complex code with and without optimization options and different levels of aggressiveness.
Try different versions of GCC