From: Maxim Levitsky <maximlevitsky@gmail.com>
To: Corrado Zoccolo <czoccolo@gmail.com>
Cc: Linux-Kernel <linux-kernel@vger.kernel.org>,
Jens Axboe <jens.axboe@oracle.com>
Subject: Re: Low latency I/O scheduling
Date: Sat, 20 Jun 2009 00:26:27 +0300 [thread overview]
Message-ID: <1245446787.5475.14.camel@localhost> (raw)
In-Reply-To: <4e5e476b0906081040l4a188b2fwad27ebe715b61daf@mail.gmail.com>
On Mon, 2009-06-08 at 19:40 +0200, Corrado Zoccolo wrote:
> Hi,
> sometime ago on the mailing list, the issue of too high latencies
> introduced by I/O scheduling was raised.
> I've done some study, and identified a way to improve on workloads
> that have >1 random readers.
You can say that again....
While there was all the fuzz about CPU scheduler, just doing some heavy
IO can literally stall the system for minutes (and I am not talking
about swap trashing, I have here 2 GB, and about 400 MB used)
Sometimes it goes so far, that I have to suspend the offending process.
I mostly compile stuff, buf file copies have even worse effect.
I tried CFQ, AS, and didn't see much difference
(but ionice on CFQ really helps)
Best regards,
Maxim Levitsky
prev parent reply other threads:[~2009-06-19 21:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-08 17:40 Low latency I/O scheduling Corrado Zoccolo
2009-06-19 21:26 ` Maxim Levitsky [this message]
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