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From: Andi Kleen <ak@linux.intel.com>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf auxtrace: Fix auxtrace queue conflict
Date: Mon, 8 Mar 2021 08:54:37 -0800	[thread overview]
Message-ID: <20210308165437.GA203350@tassilo.jf.intel.com> (raw)
In-Reply-To: <20210308151143.18338-1-adrian.hunter@intel.com>

On Mon, Mar 08, 2021 at 05:11:43PM +0200, Adrian Hunter wrote:
> The only requirement of an auxtrace queue is that the buffers are in
> time order.  That is achieved by making separate queues for separate
> perf buffer or AUX area buffer mmaps.
> 
> That generally means a separate queue per cpu for per-cpu contexts,
> and a separate queue per thread for per-task contexts.
> 
> When buffers are added to a queue, perf checks that the buffer cpu
> and thread id (tid) match the queue cpu and thread id.
> 
> However, generally, that need not be true, and perf will queue
> buffers correctly anyway, so the check is not needed.
> 
> In addition, the check gets erroneously hit when using sample mode
> to trace multiple threads.
> 
> Consequently, fix that case by removing the check.

Thanks!

Reviewed-by: Andi Kleen <ak@linux.intel.com>

-Andi

  reply	other threads:[~2021-03-08 16:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-08 15:11 [PATCH] perf auxtrace: Fix auxtrace queue conflict Adrian Hunter
2021-03-08 16:54 ` Andi Kleen [this message]
2021-03-09 12:35   ` Arnaldo Carvalho de Melo

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