From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Borzenkov, Andrey" <andrey.borzenkov@ts.fujitsu.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: Extermeley large PageTables over 500G on kernel 2.6.32.49 (SLES11 SP1)
Date: Wed, 11 Jan 2012 12:19:40 +0100 [thread overview]
Message-ID: <1326280780.2767.11.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> (raw)
In-Reply-To: <CB1B361E45A85849902B25342E88900501CFDC311187@ABGEX70E.FSC.NET>
Le mercredi 11 janvier 2012 à 11:52 +0100, Borzenkov, Andrey a écrit :
> Colleagues responsible for Oracle are reconfiguring it now.
>
OK. Since your hardware supports 1GB hugepages, you might try to use
them as well. Not sure if your kernel is recent enough...
cat /proc/cmdline
ro root=LABEL=/ hugepagesz=1GB hugepages=512
> > If not, its normal to eat so much memory for page tables
> >
> > grep VmPTE /proc/*/status
> >
> >
>
> Forgive my ignorance. I thought that
>
> 1. PTE is 8 bytes per page, which is 4K which gives 2K per 1M of memory
> 2. All processes sharing the same shared memory share the same page table
It depends how oracle maps its SGA.
It probably uses a method disallowing page table sharing.
Anyway, hugetables for this kind of workload is a must.
next prev parent reply other threads:[~2012-01-11 11:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 10:18 Borzenkov, Andrey
2012-01-11 10:36 ` Eric Dumazet
2012-01-11 10:52 ` Borzenkov, Andrey
2012-01-11 11:19 ` Eric Dumazet [this message]
2012-01-11 11:23 ` Borzenkov, Andrey
2012-01-11 11:26 ` Avi Kivity
2012-01-13 5:20 ` Borzenkov, Andrey
2012-01-16 15:43 ` Avi Kivity
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