![]() | |||||||||||||
Messages in this thread |
On Mon, 12 Feb 2007, Pavel Machek wrote: > Hi! > >> The kernel looks at what is using cpu _only_ during the >> timer >> interrupt. Which means if your HZ is 1000 it looks at >> what is running >> at precisely the moment those 1000 timer ticks occur. It >> is >> theoretically possible using this measurement system to >> use >99% cpu >> and record 0 usage if you time your cpu usage properly. >> It gets even >> more inaccurate at lower HZ values for the same reason. > > I have (had?) code that 'exploits' this. I believe I could eat 90% of cpu > without being noticed. Slightly changed version of hog(around 3 lines in total changed) does that easily on 2.6.18.3 on PPC. http://www.boblycat.org/~malc/apc/load-hog-ppc.png -- vale - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
| Last update: 2007-02-13 23:03 [from the cache] ©2003-2008 | |||||||||||||