Messages in this thread | | | Date | Sat, 26 Sep 2009 18:11:49 +0200 | From | Arjan van de Ven <> | Subject | Re: [RFC PATCH] perf_core: provide a kernel-internal interface to get to performance counters |
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On Sat, 26 Sep 2009 12:03:28 -0400 fche@redhat.com (Frank Ch. Eigler) wrote:
> > Arjan van de Ven <arjan@infradead.org> 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, visit http://www.lesswatts.org
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