From: Qingqing Zhou <zhouqq@cs.toronto.edu>
To: pgsql-hackers@postgresql.org
Subject: Re: poor performance with Context Switch Storm at TPC-W.
Date: Tue, 11 Jul 2006 21:06:13 +0800
Message-ID: <e907on$1csr$1@news.hub.org> (raw)
References: <200607112009.FED09315.TLPPUBIBOPuVLJL@oss.ntt.co.jp>
"Katsuhiko Okano" <okano.katsuhiko@oss.ntt.co.jp> wrote
>
> The problem has occurred in my customer.
> poor performance with Context Switch Storm occurred
> with the following composition.
> Usually, CS is about 5000, WIPS=360.
> when CSStorm occurrence, CS is about 100000, WIPS=60 or less.
>
> Intel Xeon 3.0GHz*4(2CPU * H/T ON)
> 4GB Memory
Do you have bgwriter on and what's the parameters? I read a theory somewhere
that bgwriter scan a large portion of memory and cause L1/L2 thrushing, so
with HT on, the other backends sharing the physical processor with it also
get thrashed ... So try to turn bgwriter off or turn HT off see what's the
difference.
Regards,
Qingqing
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To: pgsql-hackers@postgresql.org
Cc: zhouqq@cs.toronto.edu
Subject: Re: poor performance with Context Switch Storm at TPC-W.
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