Message-ID: <55A5595C.80403@hp.com>
Date: Tue, 14 Jul 2015 14:47:56 -0400
From: Waiman Long <waiman.long@hp.com>
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To: Peter Zijlstra <peterz@infradead.org>
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
References: <1436647018-49734-1-git-send-email-Waiman.Long@hp.com> <1436647018-49734-6-git-send-email-Waiman.Long@hp.com> <20150712082158.GR19282@twins.programming.kicks-ass.net>
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On 07/12/2015 04:21 AM, Peter Zijlstra wrote:
> 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

Will send out an updated patchset with patch-to-patch performance numbers.

Cheers,
Longman
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