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 3/7] locking/pvqspinlock: Implement wait-early for overcommitted guest
Date: Mon, 13 Jul 2015 12:50:22 -0700 [thread overview]
Message-ID: <1436817022.27924.74.camel@stgolabs.net> (raw)
In-Reply-To: <1436647018-49734-4-git-send-email-Waiman.Long@hp.com>
On Sat, 2015-07-11 at 16:36 -0400, Waiman Long wrote:
> /*
> + * Queued Spinlock Spin Thresholds
> + * -------------------------------
> + * Because of the cacheline contention effect of the ticket spinlock, the
> + * same spin threshold for queued spinlock will run a bit faster. So we set
> + * a slight larger threshold for the queue head (1.25X) while the other queue
> + * nodes will keep the same threshold.
How did you come to 1.25x? These sort of magic numbers scare me.
next prev parent reply other threads:[~2015-07-13 19:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-11 20:36 [PATCH 0/7] locking/qspinlock: Enhance pvqspinlock & introduce queued unfair lock Waiman Long
2015-07-11 20:36 ` [PATCH 1/7] locking/pvqspinlock: Only kick CPU at unlock time Waiman Long
2015-07-13 12:02 ` Peter Zijlstra
2015-07-13 12:31 ` Peter Zijlstra
2015-07-15 1:24 ` Waiman Long
2015-07-13 13:48 ` Peter Zijlstra
2015-07-14 9:31 ` Peter Zijlstra
2015-07-15 1:31 ` Waiman Long
2015-08-03 17:00 ` [tip:locking/core] " tip-bot for Waiman Long
2015-07-11 20:36 ` [PATCH 2/7] locking/pvqspinlock: Allow vCPUs kick-ahead Waiman Long
2015-07-13 13:52 ` Peter Zijlstra
2015-07-15 1:38 ` Waiman Long
2015-07-11 20:36 ` [PATCH 3/7] locking/pvqspinlock: Implement wait-early for overcommitted guest Waiman Long
2015-07-12 8:23 ` Peter Zijlstra
2015-07-13 19:50 ` Davidlohr Bueso [this message]
2015-07-15 1:39 ` Waiman Long
2015-07-11 20:36 ` [PATCH 4/7] locking/pvqspinlock: Collect slowpath lock statistics Waiman Long
2015-07-12 8:22 ` Peter Zijlstra
2015-07-14 18:48 ` Waiman Long
2015-07-11 20:36 ` [PATCH 5/7] locking/pvqspinlock: Add pending bit support Waiman Long
2015-07-12 8:21 ` Peter Zijlstra
2015-07-14 18:47 ` Waiman Long
2015-07-11 20:36 ` [PATCH 6/7] locking/qspinlock: A fairer queued unfair lock Waiman Long
2015-07-12 8:21 ` Peter Zijlstra
2015-07-14 18:47 ` Waiman Long
2015-07-14 20:45 ` Peter Zijlstra
2015-07-11 20:36 ` [PATCH 7/7] locking/qspinlock: Collect queued unfair lock slowpath statistics Waiman Long
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