lkml.org 
[lkml]   [2007]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: CPU load
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.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-
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 19:33    [W:0.038 / U:89.832 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site