From: Nick Piggin <npiggin@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Robin Holt <holt@sgi.com>, "Luck, Tony" <tony.luck@intel.com>,
Dimitri Sivanich <sivanich@sgi.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 03:00:30 +0000 [thread overview]
Message-ID: <20090107030030.GH3390@wotan.suse.de> (raw)
In-Reply-To: <1231283763.11687.135.camel@twins>
On Wed, Jan 07, 2009 at 12:16:03AM +0100, Peter Zijlstra wrote:
> >
> > But doesn't scheduler tick advance the rq->clock? Why do the others
> > need to fiddle with a remote runqueue's clock? When that cpu starts
> > taking ticks again, it will update it's rq->clock field and start the
> > processes. I guess I am a lot underinformed about the new scheduler
> > design.
>
> We try to do better than tick based time accounting these days.
But if you contain the drift to within one tick, it shouldn't be much
problem to just truncate negative deltas I would have thought? The
time between events on different CPUs is pretty fuzzy at the ns level
anyway, I think ;)
next prev parent reply other threads:[~2009-01-07 3:00 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 [this message]
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
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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