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Date: Sun, 23 May 2010 20:54:11 +0200
From: Borislav Petkov <bp@alien8.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, Frederic Weisbecker <fweisbec@gmail.com>,
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       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Lin Ming <ming.m.lin@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] perf: Add persistent events
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From: Peter Zijlstra <peterz@infradead.org>
Date: Sun, May 23, 2010 at 08:40:47PM +0200

> > > A persistent event would simply be a regular event, but created by the
> > > kernel and not tied to a file-desc's lifetime.
> > 
> > So you're saying the trace_mce_record() tracepoint for example should
> > be created completely internally in the kernel and cease to be a
> > tracepoint? Will it still be able to be selected by perf -e?
> 
> No, it should be a regular tracepoint as far as tracepoints are
> concerned.
> 
> But the only thing persistence should add is an instance of a
> perf_event, it should not modify either the perf_event nor the
> tracepoint code.

which means that subsystems which initialize earlier than perf (mce,
for example) should have to be notified when perf is ready so that they
could register a persistent event. How does that sound?

-- 
Regards/Gruss,
    Boris.