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Date: Tue, 6 Dec 2011 13:10:01 -0500
From: Jason Baron <jbaron@redhat.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
        Mike Galbraith <efault@gmx.de>, Paul Turner <pjt@google.com>,
        Arnaldo Carvalho de Melo <acme@infradead.org>
Subject: Re: [PATCH 0/3] Use jump_label for sched_feat()
Message-ID: <20111206181000.GE2449@redhat.com>
References: <20111206171534.429636558@chello.nl>
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On Tue, Dec 06, 2011 at 06:15:34PM +0100, Peter Zijlstra wrote:
> These patches implement sched_feat() using jump_labels. The first is a section
> mismatch fix. The second patch provides a little infrastructure and the third
> patch applies it to make sched_feat() use static_branch().
> 
> It uses static_branch() coupled with unlikely/likely in order to control the
> branch block position. I haven't checked if it works, but it likely doesn't,
> although it should.
> 
> 

It doesn't. I played around with unlikely/likely a bit, and it
didn't seem to make a difference. That said, jump_labels could still be
an improvement here - it be good if we had some numbers, I guess.

Thanks,

-Jason