Messages in this thread | | | Subject | Kernel 2.6 with X (xorg) 4.4 (eats more CPU power) | From | Joe Hsu <> | Date | Wed, 01 Dec 2004 18:21:45 +0800 |
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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).
Same phenomenon happened when I ran 4 mpeg4 playback programs (each 320x240, 30 frames per second, no scaling). It seems that these programs and X consume almost zero of CPU power when the KERNEL HZ is 100. (I've tried Robert Love's variable HZ patch to kernel 2.4 and change HZ to 1000........Same phenomenon as 2.6)
Could any one explain why??? Thanks. (I wish to be personally CC'ed the answers/comments posted to the list in response to your posting 'cause I do not subscribe to this mailing list.)
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