On Sunday 25 March 2007 23:06, malc wrote: > On Sun, 25 Mar 2007, Con Kolivas wrote: > > On Sunday 25 March 2007 21:46, Con Kolivas wrote: > >> On Sunday 25 March 2007 21:34, malc wrote: > >>> On Sun, 25 Mar 2007, Ingo Molnar wrote: > >>>> * Con Kolivas <[EMAIL PROTECTED]> wrote: > >>>>> For an rsdl 0.33 patched kernel. Comments? Overhead worth it? > > [..snip..] > > > --- > > Currently we only do cpu accounting to userspace based on what is > > actually happening precisely on each tick. The accuracy of that > > accounting gets progressively worse the lower HZ is. As we already keep > > accounting of nanosecond resolution we can accurately track user cpu, > > nice cpu and idle cpu if we move the accounting to update_cpu_clock with > > a nanosecond cpu_usage_stat entry. This increases overhead slightly but > > avoids the problem of tick aliasing errors making accounting unreliable. > > > > Signed-off-by: Con Kolivas <[EMAIL PROTECTED]> > > Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]> > > [..snip..] > > Forgot to mention. Given that this goes into the kernel, shouldn't > Documentation/cpu-load.txt be amended/removed?
Yes that's a good idea. Also there should be a sanity check because sometimes for some reason noone's been able to explain to me sched_clock gives a value which doesn't make sense (time appears to have gone backwards) and that will completely ruin the accounting from then on. -- -ck - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
