From: Jeff Dike <jdike@addtoit.com>
To: Hrishikesh <hrishikesh.amur@gmail.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] Dramatic drop in C3 state residency with NO_HZ patches
Date: Tue, 23 Oct 2007 17:35:45 -0400 [thread overview]
Message-ID: <20071023213545.GA11026@c2.user-mode-linux.org> (raw)
In-Reply-To: <1f154f440710231221r76d63ec2h640e95c7afa05a6a@mail.gmail.com>
On Tue, Oct 23, 2007 at 04:21:03PM -0300, Hrishikesh wrote:
> Yes, that double negative was a slipup. I did get some numbers out and they
> look pretty good. I ran upto 5 instances of UML simultaneously and in the
> tickful case, each instance adds roughly about 100 wakeups per second.
HZ == 100, so that makes sense.
> So
> after 5 instances, C3 residency comes down to about 95% when all the
> instances are simply idling. With NO_HZ applied, the change is minimal with
> C3 residency still approximately 98%. UML is not even among the top three of
> the bad-list of wakers-up :-)
Cool. I'm suprised that 500 wakeups/sec only brings you down < 5%.
So, things are good, except I need to figure out the !NO_HZ busy loop.
Jeff
--
Work email - jdike at linux dot intel dot com
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next prev parent reply other threads:[~2007-10-23 21:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-17 2:36 [uml-devel] Dramatic drop in C3 state residency with NO_HZ patches Hrishikesh
2007-10-17 15:55 ` Jeff Dike
2007-10-17 16:16 ` Hrishikesh
2007-10-17 17:19 ` Jeff Dike
2007-10-17 19:43 ` Hrishikesh
2007-10-17 20:45 ` Jeff Dike
2007-10-17 23:29 ` Hrishikesh
2007-10-18 20:04 ` Jeff Dike
2007-10-23 19:21 ` Hrishikesh
2007-10-23 21:35 ` Jeff Dike [this message]
2007-10-23 23:53 ` Hrishikesh
2007-10-18 8:06 ` Hrishikesh
2007-11-06 18:02 ` Jeff Dike
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