I'm trying to write an application to display multiple video streams, all updating at 25 or 30 images per second. The images are being rendered into WPF controls using Direct3D and some Interop to avoid using a Winforms control. As more video streams are added, the frame rate of each control drops yet the CPU on my machine only ever reaches about 50%.
Using the Microsoft WPF Performance Suite - Perforator tool, it would appear that when the frame rate on the video streams starts to drop, the 'Dirty Rect Addition Rate' levels out like it has reached a maximum for the video card.
There is no software rendering activity in the application so it would appear that overall performance is being limited by the graphics card's ability to update the Dirty Rectangles.
Therefore, is there a feature or performance parameter that can be used to determine the best video card to buy in order to maximise performance for my application?
Either that, or is there a set of graphics cards settings that will boost performance?
Currently running with an ATI FirePro V4800 that will happily run 16 streams of H264 video at a resolution of 4CIF but looking for the ability to run up to 32.
Related
I have a WPF Canvas with about 240 paths. A path may go out to column 550 when I look at it in Visual Studio. It's a picture of a handheld remote with many buttons that was originally exported from adobe illustrator.
On a dual core machine, 4gb, when I show the graphic, it can spike the processor from a normal of about 10% up to 30% to 40% and it will stay there. There's nothing going on, just sitting there. Probably nothing special with respect to the graphic card. If I hide the graphic, the CPU usage will drop back down.
On a better machine with more cores (I7) and a better graphics card, the change is not really noticeable, but still a spike none the less.
Anyone share a similar experience?
WPF need powerful processor to work smoothly. But in case of lower h/w it gives lower performance, specially when animation is used.
Reduce the frame rate of animation
Do not use transparency unless it is required
Use dispatcher to smooth the UI
We were able to solve a high CPU usage problem by taking advantage of Silverlight's bitmap cache, as described here:
Silverlight 3 and GPU Acceleration
Discovering Silverlight 3 – Deep Dive into GPU Acceleration
We added the EnableGPUAcceleration parameter to the <object> tag. To bring the CPU usage down to a reasonable level, we had to add CacheMode="BitmapCache" to the root visual grid for the whole app. So I'm wondering if there's any downside to relying so much on the bitmap cache. If it was always beneficial, I assume it would be enabled by default.
I found this similar question with a good answer by AnthonyWJones:
Any reason not to check “application library caching” and “GPU acceleration” in silverlight apps?
So one downside is that it uses more video RAM. I guess this could make things worse for other graphics-intensive apps running at the same time. Are there any other downsides?
If the graphics card doesn't have enough video RAM to cache everything, I assume Silverlight will degrade gracefully and will just use more CPU cycles to re-render the UI.
Thanks for your help,
Richard
After experimenting a great deal with bitmap caching, we ended up turning it off in our application. It works well when you're wanting to use the GPU to execute transforms on a piece of your UI that isn't changing -- for instance, if you have a picture that you want to animate, squish, rotate, etc. But bitmap caching/GPU acceleration (in its current implementation) slows things down pretty dramatically if you're continuing to update the visual tree inside the part of your UI that you'd like to cache/manipulate. If you're just moving around a static bitmap, it makes sense to cache it and use the GPU to accelerate it. But quite often, you might be tweaking pieces somewhere down the visual tree from the piece of your UI that you flagged to cache, and if that's happening, you need to update the GPU's cache each frame, and that's slow, slow, slow.
In other words, whether it makes sense for you to turn it on or not depends entirely on where you turn it on, and what your application is doing. Because of this, my strong recommendation, if you're using bitmap caching, or if you're experiencing performance problems with your Silverlight UI, is to (temporarily) enable cache visualization and redraw regions. Makes your app look funky as hell when they're on, but they're invaluable when it comes to seeing what your UI is doing that's chewing up all your CPU.
I don't see concerns in what you described, but I believe you can over use bitmap caching.
Say for instance you had a 500x500 'top' canvas, and it contained 25 'sub' canvases each 100x100. Lets say we were updating content/colors, etc.. in each of the sub canvases. Lets say there was an event that would move the top canvas on the screen. If all the sub canvases changed at the same interval, it would make sense to only bitmap cache the top canvas. However, if the sub canvases did not all change at the same interval, or sometimes not at all, it could turn out to be more benefitial to set bitmap caching on each sub canvas instead. Taking this one step further If you bitmap cached both the top and each sub canvas, there could be wasted cycles in caching something with no benefit.
Or am I going down a completely different path than what you are asking?
I'm getting from our hardware device (FPGA) roughly 20 frames per second (500x500 px) and I would like to render them as fast as possible. We basically get a frame buffer every 50 msec and if my rendering is too slow - well... I'm skipping frames.
My problem is to render from a C++/CLI driver to a WPF-based application. I know it's possible to host a DirectX window in a WPF aplication. What would be the fastest solution ?
InteropBitmap is the fastest way to update video frames. It's a bit more complicated than WriteableBitmap, but worth it for the performance.
I have an example here in one of my OSS projects. It's hard-coded for 32 RGBA, but you can modify it for 24bit.
http://silverlightviewport.codeplex.com/SourceControl/changeset/view/39341#809062
D3DImage is another fast way, but might be overkill in your situation.
So, I'm building a WPF app and did a test deployment today, and found that it performed pretty poorly. I was surprised, as we are really not doing much in the way of visual effects or animations.
I deployed on two machines: the fastest and the slowest that will need to run the application (the slowest PC has an Intel Celeron 1.80GHz with 2GB RAM). The application ran pretty well on the faster machine, but was choppy on the slower machine. And when I say "choppy", I mean the cursor jumped even just passing it over any open window of the app that had focus.
I opened the Task Manager Performance window, and could see that the CPU usage jumped whenever the app had focus and the cursor was moving over it. If I gave focus to another (e.g. Excel), the CPU usage went back down after a second. This happened on both machines, but the choppiness was only noticeable on the slower machine. I had very limited time to tinker on the deployment machines, so didn't do a lot of detailed testing.
The app runs fine on my development machine, but I also see the CPU spiking up to 10% there, just running the cursor over the window.
I downloaded the WPF performance tool from MS and have been tinkering with it (on my dev machine). The docs say this about the "Frame Rate" metric in the Perforator tool:
For applications without animation,
this value should be near 0.
The app is not doing any heavy animation, but the frame rate stays near 50 when the cursor is over any window. The screens I tested on have column headers in a grid that "highlight" and buttons that change color and appearance when scrolled over. Even moving the mouse on blank areas of the windows cause the same Frame rate and CPU usage (doesn't seem to be related to these minor animations).
(Also, I am unable to figure out how to get anything but the two default tools--Perforator and Visual Profiler--installed into the WPF performance tool. That is probably a separate question).
I also have Redgate's profiling tool, but I'm not sure if that can shed any light on rendering performance.
So, I realize this is not an easy thing to troubleshoot without specifics or sample code (which I can't post). My questions are:
What are some general things to look
for (or avoid) in the code to improve
performance?
What steps can I take using the WPF
performance tool to narrow down the
problem?
Is the PC spec listed above (Intel Celeron 1.80GHz with 2GB RAM) too slow to be running even vanilla WPF applications?
Are you applying any BitmapEffect-s to your UI elements?
They are not handled by GPU, so CPU takes care of rendering them. If not used properly (e.g. having a OuterGlowBitmapEffect applied to a large complex element) they can have terrible impact on performance.
Also, you still might want to try profiling your app with a performance profiler. Just to see if it's not your code that causes this.
This is not normal for WPF - I'd suspect one of your developers has written code that runs a timer in the background (or more likely given your description, a mouse move handler) which is affecting the UI in some way.
If you have ANTS performance profiler (it's really nice) I'd run that over your app and reproduce the problem.
Once you've done that, ANTS should tell you fairly quickly what the problem is.
If ANTS doesn't reveal anything at all, and shows you that in fact none of your code is running during this time, then I'd suspect buggy graphics card drivers.
You can test for this by disabling hardware acceleration by setting the following registry key, and trying again:
HKEY_CURRENT_USER\Software\Microsoft\Avalon.Graphics\DisableHWAcceleration to 1
Note: the DisableHWAcceleration value should be a DWORD
I have a simple fade in animation on a large Rectangle inside a ScrollViewer and I notice a significant drop in performance when I increase my windows size past a certain size.
resolution: 1650x1256 - still feels snappy and fluent (framerate between 50 and 60)
resolution: 1820x1256 - stutters and is pretty much unusable (framerate between 7 and 15)
What surprises me is that there doesn't seem to be a linear decline in performance but a rather sudden drop.
Also using Wpf Performance Tool does NOT show any software rendering and indeed my CPU doesn't seem to be doing much when the animation runs.
I would like to understand the cause of this, any hints would be appreciated.
Another possibility is that you are running out of dedicated video memory at that resolution, so DirectX is transferring a lot of data back and forth between video memory and main system memory on every frame.
Is there any way you can try a different graphics card, or one with more RAM, to see if the problem changes?
Also, does your GPU have a way to configure how much system RAM is reserved as video memory? Some do.
My guess is that you are running out of GPU memory at that point, so DirectX is dropping back to software rendering.
When you say a "viewport", do you mean a ViewPort3D, or do you mean a Viewbox? If it is a Viewport3D, is the animation really needing the 3D processing? If not, you could use 2D and use a transform to simulate 3D the way Flash applications have to do.