From: Jens Axboe <axboe@suse.de>
To: Brian Gerst <bgerst@quark.didntduck.org>
Cc: vasya vasyaev <vasya197@yahoo.com>, linux-kernel@vger.kernel.org
Subject: Re: Machine's high load when HIGHMEM is enabled
Date: Sun, 3 Nov 2002 16:00:41 +0100 [thread overview]
Message-ID: <20021103150041.GM807@suse.de> (raw)
In-Reply-To: <3DC5337C.4090506@quark.didntduck.org>
On Sun, Nov 03 2002, Brian Gerst wrote:
> vasya vasyaev wrote:
> >Hello,
> >
> >I have some strange kind of problem:
> >When HIGHMEM-enabled kernel is used, there is too high
> >CPU load on any task - computer get loaded high while
> >it is doing some minor, usual jobs (load average grows
> >significantly).
>
> 2.4 can only do I/O to and from lowmem. This means highmem pages have
2.4.19 and below, 2.4.20-pre/rc can dma to/from highmem pages just fine.
> to use bounce buffers in lowmem, and th edata is copied to/from highmem
> which is causing the cpu load. This has been corrected in 2.5, which
> can do I/O to any page the device can DMA from.
I seriously doubt this is his problem, sounds like something else. For
gzip to be disk bound (and thus bounce bound) you would need a seriously
fast cpu. And the ssh problem cannot be explained by bouncing either.
--
Jens Axboe
next prev parent reply other threads:[~2002-11-03 14:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-03 14:17 Machine's high load when HIGHMEM is enabled vasya vasyaev
2002-11-03 14:32 ` Brian Gerst
2002-11-03 15:00 ` Jens Axboe [this message]
2002-11-04 0:43 ` Denis Vlasenko
2002-11-04 18:54 ` vasya vasyaev
2002-11-04 19:27 ` Andrew Morton
2002-11-05 10:36 ` vasya vasyaev
2002-11-03 15:28 ` Martin J. Bligh
-- strict thread matches above, loose matches on Subject: below --
2002-11-04 19:49 Nakajima, Jun
2002-11-05 9:08 ` vasya vasyaev
2002-11-05 21:10 ` vasya vasyaev
2002-11-05 21:38 Nakajima, Jun
2002-11-06 10:14 ` vasya vasyaev
2002-11-06 16:51 ` Andrew Morton
2002-11-06 17:10 ` Dave Jones
2002-11-19 9:29 ` vasya vasyaev
2002-11-19 9:40 ` Andrew Morton
2002-11-20 1:03 ` Gerrit Huizenga
2002-11-19 15:35 ` Martin J. Bligh
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