Messages in this thread | | | Subject | Re: Kernel 2.6 with X (xorg) 4.4 (eats more CPU power) | From | Arjan van de Ven <> | Date | Wed, 01 Dec 2004 11:27:23 +0100 |
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On Wed, 2004-12-01 at 18:21 +0800, Joe Hsu wrote: > Dear All: > I've tried libXv to open an Video Overlay port and > XvShmPutImage for 60 frames per second. Each frame is > at a size of 800x600 using format YUYV (YUV2). Before > each XvShmPutImage, I copy 800x600x2 bytes of non-constant > data to XvImage->data. (No user interactive UI) > > And I found something interisting happened. In pentium 4 > 3.0G machine and linux kernel 2.6, X and my program total > consumes 5% of cpu resource. > > But in pentium 4 2.xG or below, it would consume 10% or > more of CPU resource. (If you try this with XFree86 4.2 and > pentium 1.xG machine, it would consume 30% or more of cpu > resource at a peak.) > > In contrast, I've tried Kernel 2.4 with same X, same > program, and same machine. It consumes almost zero of CPU > resource( no matter it runs on a P4 1.xG or P4 3.0G and no > matter it runs on 4.4 or 4.2 X-server).
reported resource usage is an estimate based on sampling. With HZ=1000 you do get a more accurate sampling of reality.....
In addition, do check if your code (or X) doesn't do timeouts of < 10 msec; in HZ=100 kernels those always delay 10 or 20 msec, while with HZ=1000 kernels the delay becomes far more accurate.
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