From: Peter Zijlstra <peterz@infradead.org>
To: Dimitri Sivanich <sivanich@sgi.com>
Cc: Robin Holt <holt@sgi.com>, Nick Piggin <npiggin@suse.de>,
"Luck, Tony" <tony.luck@intel.com>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
Greg KH <greg@kroah.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Gregory Haskins <ghaskins@novell.com>,
Tony Luck <tony.luck@gmail.com>
Subject: Re: [PATCH] configure HAVE_UNSTABLE_SCHED_CLOCK for SGI_SN systems
Date: Wed, 07 Jan 2009 16:16:14 +0100 [thread overview]
Message-ID: <1231341374.11687.303.camel@twins> (raw)
In-Reply-To: <20090107133230.GA28694@sgi.com>
On Wed, 2009-01-07 at 07:32 -0600, Dimitri Sivanich wrote:
> Peter,
>
> On Wed, Jan 07, 2009 at 10:53:57AM +0100, Peter Zijlstra wrote:
> >
> > Clock state is kept per-cpu, and locked with a spinlock. When we request
>
> Admittedly I have not looked at this possibility too closely, but my
> initial concern upon looking at sched_clock_cpu() for the UNSTABLE
> case was the lock_double_clock() and what sort of contention that
> might cause on larger systems under certain conditions.
Similar contention would already exist on rq->lock.
next prev parent reply other threads:[~2009-01-07 15:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-06 16:27 [PATCH] configure HAVE_UNSTABLE_SCHED_CLOCK for SGI_SN systems Dimitri Sivanich
2009-01-06 17:12 ` Greg KH
2009-01-06 20:15 ` Luck, Tony
2009-01-06 20:19 ` Robin Holt
2009-01-06 20:34 ` Luck, Tony
2009-01-06 20:57 ` Peter Zijlstra
2009-01-06 22:50 ` Robin Holt
2009-01-06 23:16 ` Peter Zijlstra
2009-01-07 3:00 ` Nick Piggin
2009-01-07 3:16 ` Jack Steiner
2009-01-07 7:28 ` Peter Zijlstra
2009-01-07 7:40 ` Nick Piggin
2009-01-07 9:43 ` Robin Holt
2009-01-07 9:53 ` Peter Zijlstra
2009-01-07 13:32 ` Dimitri Sivanich
2009-01-07 15:16 ` Peter Zijlstra [this message]
2009-01-15 18:48 ` Greg KH
2009-01-15 19:21 ` Luck, Tony
2009-01-22 19:04 ` Greg KH
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