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From: Andy Lutomirski <luto@amacapital.net>
Date: Mon, 20 Jun 2016 12:16:22 -0700
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Subject: Re: [PATCH] perf: add 'perf bench syscall'
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>,
        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Rik van Riel <riel@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>, clark@redhat.com,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
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On Mon, Jun 20, 2016 at 11:00 AM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:

>
> From: Josh Poimboeuf <jpoimboe@redhat.com>
> Subject: [PATCH] perf: add 'perf bench syscall'
>
> Add a basic 'perf bench syscall' benchmark which does a getppid() system
> call in a tight loop.
>

My one suggestion would be to use a different syscall than getppid(),
as getppid() can have unusual performance characteristics on kernels
with pid namespaces enabled.  I'm a fan of prctl(-1, 0, 0, 0, 0).