From: Ingo Molnar <mingo@elte.hu>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "K.Prasad" <prasad@linux.vnet.ibm.com>,
Arjan van de Ven <arjan@infradead.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
peterz@infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] perf_core: provide a kernel-internal interface to get to performance counters
Date: Mon, 5 Oct 2009 11:55:43 +0200 [thread overview]
Message-ID: <20091005095543.GA4266@elte.hu> (raw)
In-Reply-To: <20091004222838.GA5001@nowhere>
* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Can't we instead modify the perf events to be able to run on multiple
> contexts?
>
> We could change struct perf_event::ctx into a list of context and then
> attach it to several cpu contexts.
>
> The perf event struct have been designed to run on only one context so
> its structure and handling does not deal with races due to concurrent
> uses I guess. But at a first glance, few things would need to be
> modified to handle that, and at a low cost.
>
> There might be bad corner cases I forget though...
Dunno, i assumed it wouldnt be possible sanely. If you tried a patch we
could argue about the particulars ...
This would in essence create a new event type: system-wide. It doesnt
scale in its naive implementation - which would be fine for low freq
events.
We could encode it via sys_perf_event_open(pid:-1, cpu:-1).
Ingo
next prev parent reply other threads:[~2009-10-05 9:56 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-25 10:25 [RFC PATCH] perf_core: provide a kernel-internal interface to get to performance counters Arjan van de Ven
2009-09-25 10:44 ` Frederic Weisbecker
2009-09-25 11:42 ` Peter Zijlstra
2009-09-26 16:03 ` Frank Ch. Eigler
2009-09-26 16:11 ` Arjan van de Ven
2009-09-26 16:20 ` Frank Ch. Eigler
2009-09-26 18:32 ` K.Prasad
2009-09-26 18:48 ` Arjan van de Ven
2009-10-01 7:25 ` Ingo Molnar
2009-10-01 8:16 ` K.Prasad
2009-10-01 8:53 ` Ingo Molnar
2009-10-01 10:01 ` K.Prasad
2009-10-01 10:28 ` Ingo Molnar
2009-10-04 22:28 ` Frederic Weisbecker
2009-10-05 9:55 ` Ingo Molnar [this message]
2009-10-05 10:13 ` Frédéric Weisbecker
2009-10-05 7:53 ` Peter Zijlstra
2009-10-05 8:55 ` Ingo Molnar
2009-10-05 9:24 ` Frédéric Weisbecker
2009-10-05 9:48 ` Ingo Molnar
2009-10-05 10:08 ` Frédéric Weisbecker
2009-11-21 13:36 ` [tip:perf/core] perf/core: Provide " tip-bot for Arjan van de Ven
2010-02-05 15:47 ` [RFC PATCH] perf_core: provide " Christoph Hellwig
2010-02-05 17:59 ` john smith
2010-02-06 6:24 ` Arjan van de Ven
2010-02-06 11:46 ` Frederic Weisbecker
2010-02-06 14:18 ` Peter Zijlstra
2010-02-06 16:08 ` Frederic Weisbecker
2010-02-07 17:01 ` Ingo Molnar
2010-01-25 5:10 john smith
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