lkml.org 
[lkml]   [2015]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: RFC: futex_wait() can DoS the tick
From
Date
On Thu, 2015-06-11 at 10:34 +0200, Thomas Gleixner wrote:

> Can you try the following, please?
>
> Enable function tracer and hrtimer events manually. Then watch the irq
> count on cpu3. If it stalls or becomes slow, then stop the trace with
>
> echo 0 >/sys/kernel/debug/tracing/tracing_on
>
> If the overhead of the function tracer hides the problem, then try just
> with hrtimer, sched_switch and irq events.

Yeah, function tracer hides it. After some fiddling with buffer size to
be able to ever see a tick, I finally have a trace trimmed with a tick
on each end, 175ms gap between them. It's still 1.5 after xz, sending
off list.

-Mike




\
 
 \ /
  Last update: 2015-06-11 14:01    [W:0.049 / U:1.708 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site