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From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Andi Kleen <andi@firstfloor.org>, Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@kernel.org>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        David Ahern <dsahern@gmail.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
        Mike Galbraith <efault@gmx.de>, Namhyung Kim <namhyung@gmail.com>,
        Paul Mackerras <paulus@samba.org>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH v0 04/71] itrace: Infrastructure for instruction flow tracing units
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Date: Wed, 08 Jan 2014 13:53:15 +0200
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Andi Kleen <andi@firstfloor.org> writes:

>> So create two events, one for the PT stuff and one to track the
>> side-band stuff. We have a NOP event for just this purpose.
>
> Ok I guess that could work.
>
> Essentially replace the magic mmap offset with a second fd.
>
> Alex, what do you think?

Yes, that's what I suggested some time ago in [1]. A second buffer
(through another fd or otherwise) is an essential thing from my point of
view.

[1] http://marc.info/?l=linux-kernel&m=138737306725663

Regards,
--
Alex