From: Thomas Gleixner <tglx@linutronix.de>
To: James Hogan <james.hogan@imgtec.com>
Cc: linux-kernel@vger.kernel.org,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Subject: Re: [PATCH 3/5] metag: smp: don't spin waiting for CPU to start
Date: Mon, 1 Jul 2013 23:46:00 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.02.1307012342500.4013@ionos.tec.linutronix.de> (raw)
In-Reply-To: <1372694659-30176-4-git-send-email-james.hogan@imgtec.com>
On Mon, 1 Jul 2013, James Hogan wrote:
> Use a completion to block until a secondary CPU has started up, like ARM
> do, instead of a loop of udelays.
>
> On Meta, SMP is really SMT, with each "CPU" being a different hardware
> thread on the same Meta processor core, so as well as being more
> efficient and latency friendly, using a completion prevents the bogomips
> of the secondary CPU from being drastically skewed every time by the
> execution of the tight in-cache udelay loop on the other CPU.
The least of our worries is the correctness of bogomips. But if that
patch makes bogomips less bogus while fixing a real issue, please add
my
Acked-by: Thomas Gleixner <tglx@linutronix.de>
next prev parent reply other threads:[~2013-07-01 21:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-01 16:04 [PATCH 0/5] metag: smp/hotplug fixes James Hogan
2013-07-01 16:04 ` [PATCH 1/5] metag: use clear_tasks_mm_cpumask() James Hogan
2013-07-01 16:04 ` [PATCH 2/5] metag: smp: enable irqs after set_cpu_online James Hogan
2013-07-01 21:42 ` Thomas Gleixner
2013-07-02 5:57 ` Srivatsa S. Bhat
2013-07-01 16:04 ` [PATCH 3/5] metag: smp: don't spin waiting for CPU to start James Hogan
2013-07-01 21:46 ` Thomas Gleixner [this message]
2013-07-01 22:02 ` James Hogan
2013-07-02 6:12 ` Srivatsa S. Bhat
2013-07-01 16:04 ` [PATCH 4/5] metag: kick: prevent nested kick handlers James Hogan
2013-07-01 21:51 ` Thomas Gleixner
2013-07-01 22:17 ` James Hogan
2013-07-01 22:56 ` Thomas Gleixner
2013-07-02 0:00 ` James Hogan
2013-07-01 16:04 ` [PATCH 5/5] metag: cpu hotplug: route_irq: preserve irq mask James Hogan
2013-07-01 21:51 ` Thomas Gleixner
2013-07-02 6:16 ` Srivatsa S. Bhat
2013-07-02 9:59 ` James Hogan
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