lkml.org 
[lkml]   [2010]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: disabling group leader perf_event
  On 09/06/2010 02:24 PM, Peter Zijlstra wrote:
> On Mon, 2010-09-06 at 12:12 +0300, Avi Kivity wrote:
>> If I read the code correctly, disabling a group leader perf_event will
>> disable the entire group.
>>
>> Is this correct?
> Yeah, pretty much.

Well, I never liked group_leader style APIs. I like different types for
the container and the contained. But such is not unix.

>> If so, how can I disable just the event itself? Can I allocate a dummy
>> invent for the group leader so I can enable and disable each perf_event
>> in the group individually?
> Which makes me wonder why you use groups in the first place.

Basically, to read() all events in one go. I have many of them.

My current problem is that I have an event (kvm_exit) which I want to
drill down by looking at a field (exit_reason). So I create lots of
separate perf_events with a filter for each reason:
kvm_exit(exit_reason==0), kvm_exit(exit_reason==1), etc. But filters
are fairly slow (can have ~60 such events on AMD), so I want to make
this drill-down optional.

Current plan is to have a group for the basic events and another group
for the drilldown events (each per-cpu), and activate the drilldown
group on user request. perf will be able to schedule both groups
concurrently since they only contain tracepoints, yes?

--
error compiling committee.c: too many arguments to function



\
 
 \ /
  Last update: 2010-09-06 13:37    [W:0.062 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site