From: Avi Kivity <avi@redhat.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Will Deacon <will.deacon@arm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>,
"acme@ghostprotocols.net" <acme@ghostprotocols.net>,
Jason Wessel <jason.wessel@windriver.com>
Subject: Re: [PATCH 1/3] perf: add context field to perf_event
Date: Tue, 12 Jul 2011 13:07:25 +0300 [thread overview]
Message-ID: <4E1C1CDD.9040005@redhat.com> (raw)
In-Reply-To: <20110712100354.GC29812@8bytes.org>
On 07/12/2011 01:03 PM, Joerg Roedel wrote:
> > Regarding LWP - I thought the intent was self-profiling by the process
> > for jits and the like? If you also use it for perf, won't it be
> > unusable for that? Also, can't the process interfere, from userspace,
> > by executing the unprivileged LWP instructions?
>
> Ingo made perf-integration a merge-requirement for LWP. It is not really
> well-suited for being integrated into perf because the design goal was
> easy and efficient self-profiling of tasks (like you stated). So
> integrating it into perf causes some pain. But lets see how it works
> out.
I don't think it's workable. Having do_mmap() called in the task's
context can change how it works. And the task being able to kill/modify
the profile, and not able to use LWP for itself, is a show stopper IMO.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2011-07-12 10:13 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-29 15:42 [PATCH 0/3] Preparatory perf patches for KVM PMU support Avi Kivity
2011-06-29 15:42 ` [PATCH 1/3] perf: add context field to perf_event Avi Kivity
2011-06-29 16:08 ` Frederic Weisbecker
2011-06-29 16:25 ` Avi Kivity
2011-06-29 16:27 ` Will Deacon
2011-07-04 13:58 ` Frederic Weisbecker
2011-07-04 14:10 ` Avi Kivity
2011-07-04 14:36 ` Frederic Weisbecker
2011-07-11 21:07 ` Will Deacon
2011-07-12 7:20 ` Avi Kivity
2011-07-12 8:38 ` Peter Zijlstra
2011-07-12 9:08 ` Avi Kivity
2011-07-12 9:14 ` Peter Zijlstra
2011-07-12 9:16 ` Avi Kivity
2011-07-12 9:18 ` Peter Zijlstra
2011-07-12 9:27 ` Avi Kivity
2011-07-12 9:31 ` Peter Zijlstra
2011-07-12 9:36 ` Avi Kivity
2011-07-12 9:42 ` Will Deacon
2011-07-12 9:41 ` Joerg Roedel
2011-07-12 9:44 ` Avi Kivity
2011-07-12 9:48 ` Joerg Roedel
2011-07-12 9:55 ` Avi Kivity
2011-07-12 10:03 ` Joerg Roedel
2011-07-12 10:07 ` Avi Kivity [this message]
2011-07-12 10:24 ` Joerg Roedel
2011-07-12 10:36 ` Avi Kivity
2011-07-21 15:32 ` Will Deacon
2011-07-21 15:36 ` Avi Kivity
2011-07-21 15:46 ` Will Deacon
2011-07-21 15:59 ` Avi Kivity
2011-07-21 16:37 ` Will Deacon
2011-07-05 14:30 ` Will Deacon
2011-07-05 14:34 ` Frederic Weisbecker
2011-07-01 15:24 ` [tip:perf/core] perf: Add " tip-bot for Avi Kivity
2011-06-29 15:42 ` [PATCH 2/3] x86, perf: add constraints for architectural PMU v1 Avi Kivity
2011-07-01 15:24 ` [tip:perf/core] x86, perf: Add constraints for architectural PMU tip-bot for Avi Kivity
2011-06-29 15:42 ` [PATCH 3/3] perf: export perf_event_refresh() to modules Avi Kivity
2011-07-01 15:25 ` [tip:perf/core] " tip-bot for Avi Kivity
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