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Message-ID: <20110826032601.GA26282@localhost>
Date: Fri, 26 Aug 2011 11:26:02 +0800
From: Wu Fengguang <fengguang.wu@...el.com>
To: Stefan Priebe <s.priebe@...fihost.ag>
Cc: Pekka Enberg <penberg@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Mel Gorman <mel@....ul.ie>, Jens Axboe <jaxboe@...ionio.com>,
Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: slow performance on disk/network i/o full speed after
drop_caches
On Fri, Aug 26, 2011 at 11:13:07AM +0800, Stefan Priebe wrote:
>
> >> There is at least a numastat proc file.
> >
> > Thanks. This shows that node0 is accessed 10x more than node1.
>
> What can i do to prevent this or isn't this normal when a machine mostly idles so processes are mostly processed by cpu0.
Yes, that's normal. However it should explain why it's slow even when
there are lots of free pages _globally_.
> >
> >> complete ps output:
> >> http://pastebin.com/raw.php?i=b948svzN
> >
> > In that log, scp happens to be in R state and also no other tasks in D
> > state. Would you retry in the hope of catching some stucked state?
> Sadly not as the sysrq trigger has rebootet the machine and it will now run fine for 1 or 2 days.
Oops, sorry! It might be possible to reproduce the issue by manually
eating all of the memory with sparse file data:
truncate -s 1T 1T
cp 1T /dev/null
> >
> >>> echo t> /proc/sysrq-trigger
> >> sadly i wa sonly able to grab the output in this crazy format:
> >> http://pastebin.com/raw.php?i=MBXvvyH1
> >
> > It's pretty readable dmesg, except that the data is incomplete and
> > there are nothing valuable in the uploaded portion..
> That was everything i could grab through netconsole. Is there a better way?
netconsole is enough. The partial output should be due to the reboot...
Thanks,
Fengguang
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