From: John Reiser <jreiser@BitWagon.com>
To: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Bart Van Assche <bart.vanassche@gmail.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Christoph Lameter <clameter@sgi.com>,
Daniel Walker <dwalker@mvista.com>,
Andi Kleen <andi@firstfloor.org>,
Randy Dunlap <randy.dunlap@oracle.com>,
Josh Aune <luken@omner.org>, Pekka Paalanen <pq@iki.fi>
Subject: Re: [ANNOUNCE] kmemcheck v7
Date: Sun, 11 May 2008 05:08:43 -0700 [thread overview]
Message-ID: <4826E1CB.6090500@BitWagon.com> (raw)
In-Reply-To: <19f34abd0805100502k150e3636x33831230d688dd92@mail.gmail.com>
Vegard Nossum wrote:
> How is the speed of Valgrind+UML, does anybody know?
The speed of Valgrind+UML is the same as the speed of valgrind
on any application. On a 2GHz box it took about 2.5 minutes
to reach "login:" from a cold boot of UML (includes udev, etc.)
So if normal boot takes 15 seconds, then that's a factor of 10
slowdown: slow for interactivity, yet bearable for checking.
The memory-intensive portions (linear search, pointer chasing,
etc.) can be slower still, but loops that concentrate on
register arithmetic or conditional branching go faster.
There is almost no system wait time: normal device delays (disk,
network) get totally overlapped by CPU usage for grinding :-)
I'd like to have both kmemcheck and valgrind+UML, and use them
differently. Run kmemcheck all the time on a box or two as
"background trolling" for infrequent cases. Use valgrind+UML
for interactivity and programmable flexibility when hunting
specific bugs, or when hardware cannot be dedicated.
--
John Reiser, jreiser@BitWagon.com
prev parent reply other threads:[~2008-05-11 12:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-04 13:44 [ANNOUNCE] kmemcheck v7 Vegard Nossum
2008-04-04 13:45 ` [PATCH 1/3] kmemcheck: add the kmemcheck core Vegard Nossum
2008-04-04 13:46 ` [PATCH 2/3] x86: add hooks for kmemcheck Vegard Nossum
2008-04-04 13:47 ` [PATCH 3/3] slub: " Vegard Nossum
2008-05-10 9:07 ` [ANNOUNCE] kmemcheck v7 Bart Van Assche
2008-05-10 9:06 ` Pekka Enberg
2008-05-10 11:04 ` Bart Van Assche
2008-05-10 12:02 ` Vegard Nossum
2008-05-10 12:37 ` Andi Kleen
2008-05-10 13:22 ` Bart Van Assche
2008-05-10 17:17 ` Jeremy Fitzhardinge
2008-05-10 17:48 ` Andi Kleen
2008-05-10 20:45 ` Jeremy Fitzhardinge
2008-05-10 21:29 ` John Reiser
2008-05-10 23:05 ` Jeremy Fitzhardinge
2008-05-10 21:31 ` Andi Kleen
2008-05-10 22:59 ` Jeremy Fitzhardinge
2008-05-10 13:29 ` Bart Van Assche
2008-05-10 17:17 ` Jeremy Fitzhardinge
2008-05-10 20:35 ` Jeff Dike
2008-05-11 11:23 ` John Reiser
2008-05-11 12:08 ` John Reiser [this message]
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