lkml.org 
[lkml]   [2007]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: nohz and strange sleep latencies
Date
On Saturday, 24 of November 2007, Pavel Machek wrote:
> Hi!
>
> > > > but perhaps somehow we miss this fact and fail to turn off the lapic
> > > > clockevents drivers?
> > >
> > > Ok, I guess I'm lost. If I offline second CPU, I immediately get
> > > 1000Hz timer tick... is that expected?
> >
> > Hmm. No. I have no idea why this is happening.
> >
> > 34196 total events, 55.083 events/sec
> > echo 0 >/sys/devices/system/cpu/cpu1/online
> > 36073 total events, 54.679 events/sec
>
> Digging into process_32|64.c...
>
> 64:
> while (1) {
> while (!need_resched()) {
> void (*idle)(void);
>
> if (__get_cpu_var(cpu_idle_state))
> __get_cpu_var(cpu_idle_state) = 0;
>
> tick_nohz_stop_sched_tick();
>
> 32:
> while (1) {
> tick_nohz_stop_sched_tick();
> while (!need_resched()) {
> void (*idle)(void);
>
> if (__get_cpu_var(cpu_idle_state))
> __get_cpu_var(cpu_idle_state) = 0;
>
> ...eek? Which one is wrong?

Hm, it looks like you should have quoted more lines ...

In the second case (32), the tick_nohz_stop_sched_tick() seems to be
redundant, so I bet it's this one.

Greetings,
Rafael
-
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: 2007-11-25 00:15    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site