From: Peter Zijlstra <peterz@infradead.org>
To: Jan Beulich <JBeulich@novell.com>
Cc: jeremy.fitzhardinge@citrix.com, mingo@elte.hu,
tglx@linutronix.de, Ky Srinivasan <KSrinivasan@novell.com>,
linux-kernel@vger.kernel.org, hpa@zytor.com
Subject: Re: [PATCH 4/4, v2] x86: enlightenment for ticket spin locks - improve yield behavior on Xen
Date: Wed, 30 Jun 2010 11:24:14 +0200 [thread overview]
Message-ID: <1277889854.1868.104.camel@laptop> (raw)
In-Reply-To: <4C2B21300200007800008BDC@vpn.id2.novell.com>
On Wed, 2010-06-30 at 09:49 +0100, Jan Beulich wrote:
> >>> On 30.06.10 at 10:11, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Tue, 2010-06-29 at 15:35 +0100, Jan Beulich wrote:
> >>
> >> The (only) additional overhead this introduces for native execution is
> >> the writing of the owning CPU in the lock acquire paths.
> >
> > Uhm, and growing the size of spinlock_t to 6 (or 8 bytes when aligned)
> > bytes when NR_CPUS>256.
>
> Indeed, I should have mentioned that. Will do so in an eventual
> next version.
It would be good to also get a measure of data structure bloat caused by
this, not sure .data section size is representable there, but its
something easy to provide.
Something like: pahole -s build/vmlinux | awk '{t+=$2} END {print t}'
from before and after might also be interesting.
next prev parent reply other threads:[~2010-06-30 9:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 14:35 [PATCH 4/4, v2] x86: enlightenment for ticket spin locks - improve yield behavior on Xen Jan Beulich
2010-06-30 8:11 ` Peter Zijlstra
2010-06-30 8:49 ` Jan Beulich
2010-06-30 9:24 ` Peter Zijlstra [this message]
2010-06-30 10:10 ` Jeremy Fitzhardinge
2010-06-30 11:25 ` Jan Beulich
2010-06-30 10:08 ` Jeremy Fitzhardinge
2010-06-30 11:22 ` Jan Beulich
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