From: Davidlohr Bueso <dave@stgolabs.net>
To: Waiman Long <Waiman.Long@hp.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
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 v3 3/7] locking/pvqspinlock: Collect slowpath lock statistics
Date: Sun, 26 Jul 2015 18:14:34 -0700 [thread overview]
Message-ID: <1437959674.25997.30.camel@stgolabs.net> (raw)
In-Reply-To: <1437595962-21472-4-git-send-email-Waiman.Long@hp.com>
On Wed, 2015-07-22 at 16:12 -0400, Waiman Long wrote:
> This patch enables the accumulation of kicking and waiting related
> PV qspinlock statistics when the new QUEUED_LOCK_STAT configuration
> option is selected. It also enables the collection of kicking and
> wakeup latencies which have a heavy dependency on the CPUs being used.
>
> The measured latencies for different CPUs are:
>
> CPU Wakeup Kicking
> --- ------ -------
> Haswell-EX 89.8us 7.4us
> Westmere-EX 67.6us 9.3us
>
But you don't mention anything about the overhead of enabling
QUEUED_LOCK_STAT. This does several atomic ops, thus potentially
thrashing workloads.
next prev parent reply other threads:[~2015-07-27 1:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-22 20:12 [PATCH v3 0/7] locking/qspinlock: Enhance pvqspinlock performance Waiman Long
2015-07-22 20:12 ` [PATCH v3 1/7] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Waiman Long
2015-07-25 22:31 ` Davidlohr Bueso
2015-07-27 1:46 ` Davidlohr Bueso
2015-07-27 17:50 ` Waiman Long
2015-07-27 18:41 ` Davidlohr Bueso
2015-07-31 8:39 ` Peter Zijlstra
2015-07-31 17:01 ` Waiman Long
2015-07-22 20:12 ` [PATCH v3 2/7] locking/pvqspinlock: Add pending bit support Waiman Long
2015-07-26 23:09 ` Davidlohr Bueso
2015-07-27 17:11 ` Waiman Long
2015-07-26 23:48 ` Davidlohr Bueso
2015-07-27 0:56 ` Davidlohr Bueso
2015-07-27 17:30 ` Waiman Long
2015-07-27 19:39 ` Davidlohr Bueso
2015-07-29 20:49 ` Waiman Long
2015-07-27 20:08 ` Davidlohr Bueso
2015-07-22 20:12 ` [PATCH v3 3/7] locking/pvqspinlock: Collect slowpath lock statistics Waiman Long
2015-07-27 1:14 ` Davidlohr Bueso [this message]
2015-07-27 17:33 ` Waiman Long
2015-07-22 20:12 ` [PATCH v3 4/7] locking/pvqspinlock: Enable deferment of vCPU kicking to unlock call Waiman Long
2015-07-22 20:12 ` [PATCH v3 5/7] locking/pvqspinlock: Allow vCPUs kick-ahead Waiman Long
2015-07-22 20:12 ` [PATCH v3 6/7] locking/pvqspinlock: Queue node adaptive spinning Waiman Long
2015-07-22 20:12 ` [PATCH v3 7/7] locking/pvqspinlock, x86: Optimize PV unlock code path Waiman Long
2015-07-27 1:18 ` [PATCH v3 0/7] locking/qspinlock: Enhance pvqspinlock performance Davidlohr Bueso
2015-07-27 17:36 ` Waiman Long
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