[lkml]   [2009]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH] perf_core: provide a kernel-internal interface to get to performance counters
On Sat, 26 Sep 2009 12:03:28 -0400 (Frank Ch. Eigler) wrote:

> Arjan van de Ven <> writes:
> > [...]
> > There are reasons for kernel code to ask for, and use, performance
> > counters. For example, in CPU freq governors this tends to be a
> > good idea, but there are other examples possible as well of course.
> >
> > This patch adds the needed bits to do enable this functionality;
> > they have been tested in an experimental cpufreq driver that I'm
> > working on, and the changes are all that I needed to access
> > counters properly. [...]
> For what it's worth, this sort of thing also looks useful from
> systemtap's point of view.
> It appears that the patch assumes that a perf counter instance is to
> be associated with the "current" task. How do you use this from your
> prototype scheduler? Do you create/attach a new one for each thread?

your appearance is not correct. A perf counter is either attached to a
task, or to a cpu. I use the later.

Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,

 \ /
  Last update: 2009-09-26 18:15    [W:0.129 / U:0.784 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site