Date: Sun, 12 Jul 2015 10:21:58 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <Waiman.Long@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, Scott J Norton <scott.norton@hp.com>,
        Douglas Hatch <doug.hatch@hp.com>
Subject: Re: [PATCH 5/7] locking/pvqspinlock: Add pending bit support
Message-ID: <20150712082158.GR19282@twins.programming.kicks-ass.net>
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On Sat, Jul 11, 2015 at 04:36:56PM -0400, Waiman Long wrote:
> Like the native qspinlock, using the pending bit when it is lightly
> loaded to acquire the lock is faster than going through the PV queuing
> process which is even slower than the native queuing process. It also
> avoids loading two additional cachelines (the MCS and PV nodes).
> 
> This patch adds the pending bit support for PV qspinlock. The
> pending bit code has a smaller spin threshold. It will default back
> to the queuing method if it cannot acquired the lock within a certain
> time limit.

-ENONUMBERS
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