From: Olaf Hering <olh@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>,
Hannes Reinecke <hare@suse.de>,
linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
Subject: Re: calibrate_migration_costs takes ages on s390
Date: Tue, 14 Feb 2006 00:42:54 +0100 [thread overview]
Message-ID: <20060213234254.GA5368@suse.de> (raw)
In-Reply-To: <20060213104645.GA17173@elte.hu>
On Mon, Feb 13, Ingo Molnar wrote:
>
> * Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
>
> > The boot sequence on s390 sometimes takes ages and we spend a very
> > long time (up to one or two minutes) in calibrate_migration_costs. The
> > time spent there differs from boot to boot. Also the calculated costs
> > differ a lot. I've seen differences by up to a factor of 15 (yes,
> > factor not percent). Also I doubt that making these measurements make
> > much sense on a completely virtualized architecture where you cannot
> > tell how much cpu time you will get anyway. Is there any workaround or
> > fix available so we can avoid seeing this?
>
> which is the precise kernel version used? We toned down calibration a
> bit recently.
We did a bit of testing, -rc2-git3 + the patch below was still ok.
[PATCH] s390: earlier initialization of cpu_possible_map
9733e2407ad2237867cb13c04e7d619397fa3090
next prev parent reply other threads:[~2006-02-13 23:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-13 10:26 calibrate_migration_costs takes ages on s390 Heiko Carstens
2006-02-13 10:34 ` David S. Miller
2006-02-13 10:54 ` Ingo Molnar
2006-02-13 20:57 ` David S. Miller
2006-02-13 10:46 ` Ingo Molnar
2006-02-13 16:13 ` Heiko Carstens
2006-02-13 23:42 ` Olaf Hering [this message]
2006-02-14 0:08 ` Olaf Hering
2006-02-14 8:09 ` Heiko Carstens
2006-02-14 10:56 ` Heiko Carstens
2006-02-14 12:35 ` Ingo Molnar
2006-02-14 12:37 ` Ingo Molnar
2006-02-16 6:27 ` Heiko Carstens
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