From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Nick Piggin <piggin@cyberone.com.au>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: blk_congestion_wait racy?
Date: Thu, 11 Mar 2004 19:24:48 +0100 [thread overview]
Message-ID: <OF214BC5A0.606D60A9-ONC1256E53.0034F9B5-C1256E54.006525C2@de.ibm.com> (raw)
> Martin, have you tried adding this printk?
Sorry for the delay. I had to get 2.6.4-mm1 working before doing the
"ouch" test. The new pte_to_pgprot/pgoff_prot_to_pte stuff wasn't easy.
I tested 2.6.4-mm1 with the blk_run_queues move and the ouch printk.
The first interesting observation is that 2.6.4-mm1 behaves MUCH better
then 2.6.4:
2.6.4-mm1 with 1 cpu
# time ./mempig 600
Count (1Meg blocks) = 600
600 of 600
Done.
real 0m2.587s
user 0m0.100s
sys 0m0.730s
#
2.6.4-mm1 with 2 cpus
# time ./mempig 600
Count (1Meg blocks) = 600
600 of 600
Done.
real 0m10.313s
user 0m0.160s
sys 0m0.780s
#
2.6.4 takes > 1min for the test with 2 cpus.
The second observation is that I get only a few "ouch" messages. They
all come from the blk_congestion_wait in try_to_free_pages, as expected.
What I did not expect is that I only got 9 "ouches" for the run with
2 cpus.
blue skies,
Martin
Linux/390 Design & Development, IBM Deutschland Entwicklung GmbH
Schonaicherstr. 220, D-71032 Boblingen, Telefon: 49 - (0)7031 - 16-2247
E-Mail: schwidefsky@de.ibm.com
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next reply other threads:[~2004-03-11 18:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-11 18:24 Martin Schwidefsky [this message]
2004-03-11 18:55 ` Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2004-03-11 19:04 Martin Schwidefsky
2004-03-11 23:25 ` Andrew Morton
2004-03-12 2:31 ` Nick Piggin
2004-03-09 17:54 Martin Schwidefsky
2004-03-10 5:23 ` Nick Piggin
2004-03-10 5:35 ` Andrew Morton
2004-03-10 5:47 ` Nick Piggin
2004-03-08 13:38 Martin Schwidefsky
2004-03-08 23:50 ` Nick Piggin
2004-03-08 9:59 Martin Schwidefsky
2004-03-08 12:24 ` Andrew Morton
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