Messages in this thread | | | Date | Tue, 26 Apr 2011 16:05:57 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 02/18] perf: Add persistent event facilities |
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On Tue, Apr 26, 2011 at 08:45:10AM -0400, Ingo Molnar wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > > > On Sat, 2011-04-23 at 18:28 +0200, Borislav Petkov wrote: > > > From: Borislav Petkov <borislav.petkov@amd.com> > > > > > > Add a barebones implementation for registering persistent events with > > > perf. For that, we don't destroy the buffers when they're unmapped and > > > we map them read-only so that multiple agents can access them. > > > > > > Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> > > > --- > > > include/linux/perf_event.h | 22 ++++++++++++++++- > > > kernel/events/Makefile | 2 +- > > > kernel/events/core.c | 30 ++++++++++++++++++---- > > > kernel/events/persistent.c | 56 ++++++++++++++++++++++++++++++++++++++++++++ > > > 4 files changed, 102 insertions(+), 8 deletions(-) > > > create mode 100644 kernel/events/persistent.c > > > > > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > > > index ee9f1e7..37bfae1 100644 > > > --- a/include/linux/perf_event.h > > > +++ b/include/linux/perf_event.h > > > @@ -216,8 +216,9 @@ struct perf_event_attr { > > > precise_ip : 2, /* skid constraint */ > > > mmap_data : 1, /* non-exec mmap data */ > > > sample_id_all : 1, /* sample_type all events */ > > > + persistent : 1, /* event always on */ > > > > But how will you find it again? > > > > Persistent yells filesystem to me, and while we didn't use relayfs for > > various reasons, I think we do need something like it at the current stage. > > eventfs or sysfs? > > We need VFS space for event hierarchy enumeration anyway (and move the current > debugfs bits there). Persistent events could show up in that hiearachy as well.
I think we talked about this already in conjunction with moving event hierarchy to sysfs - there you can have a "persistent" node too so you can find it.
Here's what we talked about then:
https://lkml.org/lkml/2010/11/11/10
this and the following messages.
-- Regards/Gruss, Boris.
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