From: Peter Zijlstra <peterz@infradead.org>
To: Jan Beulich <JBeulich@novell.com>
Cc: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com,
jeremy.fitzhardinge@citrix.com,
Ky Srinivasan <KSrinivasan@novell.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4, v2] x86: enlightenment for ticket spin locks - base implementation
Date: Wed, 30 Jun 2010 10:05:33 +0200 [thread overview]
Message-ID: <1277885133.1868.71.camel@laptop> (raw)
In-Reply-To: <4C2A1FE902000078000089E1@vpn.id2.novell.com>
On Tue, 2010-06-29 at 15:31 +0100, Jan Beulich wrote:
> Add optional (alternative instructions based) callout hooks to the
> contended ticket lock and the ticket unlock paths, to allow hypervisor
> specific code to be used for reducing/eliminating the bad effects
> ticket locks have on performance when running virtualized.
Uhm, I'd much rather see a single alternative implementation, not a
per-hypervisor lock implementation.
> For the moment, this isn't intended to be used together with pv-ops,
> but this is just to simplify initial integration. The ultimate goal
> for this should still be to replace pv-ops spinlocks.
So why not start by removing that?
> +config ENLIGHTEN_SPINLOCKS
Why exactly are these enlightened? I'd say CONFIG_UNFAIR_SPINLOCKS would
be much better.
> +#define X86_FEATURE_SPINLOCK_YIELD (3*32+31) /* hypervisor yield interface */
That name also sucks chunks, yield isn't a lock related term.
> +#define ALTERNATIVE_TICKET_LOCK \
But but but, the alternative isn't a ticket lock..!?
next prev parent reply other threads:[~2010-06-30 8:05 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 14:31 [PATCH 1/4, v2] x86: enlightenment for ticket spin locks - base implementation Jan Beulich
2010-06-30 8:05 ` Peter Zijlstra [this message]
2010-06-30 9:00 ` Jan Beulich
2010-06-30 9:11 ` Peter Zijlstra
2010-06-30 9:56 ` Jeremy Fitzhardinge
2010-06-30 11:43 ` Jan Beulich
2010-06-30 11:48 ` Peter Zijlstra
2010-06-30 11:54 ` Jan Beulich
2010-06-30 10:50 ` Jeremy Fitzhardinge
2010-06-30 11:52 ` Jan Beulich
2010-06-30 12:53 ` Jeremy Fitzhardinge
2010-06-30 13:21 ` Jan Beulich
2010-06-30 13:28 ` Jeremy Fitzhardinge
2010-06-30 9:26 ` Peter Zijlstra
2010-06-30 9:32 ` Gleb Natapov
2010-06-30 8:24 ` Peter Zijlstra
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