lkml.org 
[lkml]   [2011]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: perf: regression with PERF_EVENT_IOC_REFRESH
On Sat, 28 May 2011, Peter Zijlstra wrote:

> On Fri, 2011-05-27 at 23:38 -0400, Vince Weaver wrote:
> > on that note (and while trying to document exactly what the ioctls do) it
> > seems that a PERF_EVENT_IOC_REFRESH with an argument of anything higher
> > than one does not work on kernels 2.6.36 and newer. The behavior acts
> > as if 1 was passed, even if you pass in, say, 3.
>
> Urgh, no that should definitely work. Thanks for the test-case, I'll
> work on that (probably not until Monday though, but who knows).
>

after a painfully long bisection, it turns out that this problem was in
theory introduced by the following commit:

d57e34fdd60be7ffd0b1d86bfa1a553df86b7172

perf: Simplify the ring-buffer logic: make perf_buffer_alloc() do everything needed

I'll see if I can come up with a patch, but it's a bit non-obvious why
this commit is affecting the REFRESH value at all.

Vince
vweaver1@eecs.utk.edu


\
 
 \ /
  Last update: 2011-05-29 18:57    [W:0.070 / U:29.264 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site