Thread execution time in C/Linux - c

Question

Wandering if I can measure actual time or cpu ticks taken by a particular thread.
pthreadcreate(.........);
//
//
pthreadjoin(.......);
I am running with 3 threads.
One master thread is calling the rest two threads.
I want to measure the execution time for a called thread.
what should I use in linux environment ?

Answer 1

you can do one thing
In thread function at start up make a log using printk. You can separate it with different thread printing with it thread_t variable or thread index
and at end of that thread function put another log like that.
So in dmesg
will shows the log with timestamp
so you can differentiate end log time with start log time.
I know this is not more practical way of doing this but just for debugging purpose you can do this without much effort.

Answer 2

If you want to have a more accurate result you can use tick counters :
#ifndef TIMING_H
#define TIMING_H
/*
* -- Init timing library with timing_init();
* -- get timestamp :
* tick_t t;
* GET_TICK(t);
* -- get delay between two timestamps in microseconds :
* TIMING_DELAY(t1, t2);
*/
#include <sys/time.h>
#include <unistd.h>
#include <stdint.h>
#ifndef min
#define min(a,b) \
({__typeof__ ((a)) _a = (a); \
__typeof__ ((b)) _b = (b); \
_a < _b ? _a : _b; })
#endif
typedef union u_tick
{
uint64_t tick;
struct
{
uint32_t low;
uint32_t high;
}
sub;
} tick_t;
static double scale_time = 0.0;
static unsigned long long residual = 0;
#if defined(__i386__) || defined(__pentium__) || defined(__pentiumpro__) || defined(__i586__) || defined(__i686__) || defined(__k6__) || defined(__k7__) || defined(__x86_64__)
# define GET_TICK(t) __asm__ volatile("rdtsc" : "=a" ((t).sub.low), "=d" ((t).sub.high))
#else
# error "Unsupported processor"
#endif
#define TICK_RAW_DIFF(t1, t2) ((t2).tick - (t1).tick)
#define TICK_DIFF(t1, t2) (TICK_RAW_DIFF(t1, t2) - residual)
#define TIMING_DELAY(t1, t2) tick2usec(TICK_DIFF(t1, t2))
void timing_init(void)
{
static tick_t t1, t2;
int i;
residual = (unsigned long long)1 << 63;
for(i = 0; i < 20; i++)
{
GET_TICK(t1);
GET_TICK(t2);
residual = min(residual, TICK_RAW_DIFF(t1, t2));
}
{
struct timeval tv1,tv2;
GET_TICK(t1);
gettimeofday(&tv1,0);
usleep(500000);
GET_TICK(t2);
gettimeofday(&tv2,0);
scale_time = ((tv2.tv_sec*1e6 + tv2.tv_usec) -
(tv1.tv_sec*1e6 + tv1.tv_usec)) /
(double)(TICK_DIFF(t1, t2));
}
}
double tick2usec(long long t)
{
return (double)(t)*scale_time;
}
#endif /* TIMING_H */