From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Lin Ming <ming.m.lin@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Tim Blechmann <tim@klingt.org>, David Ahern <dsahern@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] perf: Allow set output buffer for tasks in the same thread group
Date: Sun, 24 Apr 2011 19:05:26 +0200 [thread overview]
Message-ID: <1303664726.20212.1.camel@twins> (raw)
In-Reply-To: <1303657064.2239.25.camel@localhost>
On Sun, 2011-04-24 at 22:57 +0800, Lin Ming wrote:
> Currently, kernel only allows an event to redirect its output to other
> events of the same task.
>
> This causes PERF_EVENT_IOC_SET_OUTPUT ioctl fails when an event is
> trying to redirect its output to other events in the same thread group.
Which is exactly what it should do, you should never be allowed to
redirect your events to that of another task, since that other task
might be running on another CPU.
The buffer code strictly assumes no concurrency, therefore its either
one task or one CPU.
next prev parent reply other threads:[~2011-04-24 17:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-24 14:57 [PATCH] perf: Allow set output buffer for tasks in the same thread group Lin Ming
2011-04-24 17:05 ` Peter Zijlstra [this message]
2011-04-25 13:40 ` Lin Ming
2011-04-25 15:28 ` Arnaldo Carvalho de Melo
2011-04-26 20:44 ` [PATCH RFC] Fix per-task profiling " Arnaldo Carvalho de Melo
2011-04-26 21:28 ` David Ahern
2011-04-27 2:40 ` Lin Ming
2011-04-27 16:07 ` Arnaldo Carvalho de Melo
2011-05-15 17:49 ` [tip:perf/urgent] perf tools: Honour the cpu list parameter when also monitoring a thread list tip-bot for Arnaldo Carvalho de Melo
2011-05-15 17:49 ` [tip:perf/urgent] perf evlist: Fix per thread mmap setup tip-bot for Arnaldo Carvalho de Melo
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