From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, Jens Axboe <jens.axboe@oracle.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH RFC 3/3] x86: use mwait for trigger API
Date: Sat, 16 Aug 2008 14:50:34 -0700 [thread overview]
Message-ID: <48A74BAA.4010908@goop.org> (raw)
In-Reply-To: <20080816104404.070e0c14@infradead.org>
Arjan van de Ven wrote:
> monitor/mwait is rather really expensive.. are we really sure we want
> to use this?
> (from an Intel cpu perspective the answer is very likely no; but I don't
> know what AMD does here)
>
The intended use is when you're going to be waiting for a while (on the
order of microseconds or more). In the Xen case, I use this to block
the vcpu if we pass a few iterations without the condition being true.
While the mwait patch doesn't do this at present, it could.
J
next prev parent reply other threads:[~2008-08-16 21:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-16 16:34 [PATCH RFC 3/3] x86: use mwait for trigger API Jeremy Fitzhardinge
2008-08-16 17:44 ` Arjan van de Ven
2008-08-16 21:50 ` Jeremy Fitzhardinge [this message]
2008-08-16 22:31 ` Arjan van de Ven
2008-08-28 12:25 ` Christian Borntraeger
2008-08-28 17:33 ` Jeremy Fitzhardinge
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