From: Christoph Hellwig <hch@lst.de>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: trying to understand READ_META, READ_SYNC, WRITE_SYNC & co
Date: Wed, 23 Jun 2010 12:02:52 +0200 [thread overview]
Message-ID: <20100623100252.GB9575@lst.de> (raw)
In-Reply-To: <20100621202504.GA6474@redhat.com>
On Mon, Jun 21, 2010 at 04:25:04PM -0400, Vivek Goyal wrote:
> In my testing in the past, this was helping if lots of sequential readers
> are running in a system (with 100ms slice each) and if there is another
> reader doing small file reads. Without meta data based preemption check,
> latency of opening small file used to be very high (Because all the sync
> sequntial reader gets to consume their 100ms slices first).
>
> Situation should be somewhat better now after corrado's changes of
> reducing slice length dynamically. But I suspect that we will still
> experience significantly reduced latency for small file reads in presece
> of multiple sequntial reads going on.
Any chance we could create a benchmark suite for the I/O schedulers?
I'd really like to get these annotations correct, and having an
automated suite that shows the numbers for the interesting workloads
would help greatly with that.
prev parent reply other threads:[~2010-06-23 10:03 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-21 9:48 trying to understand READ_META, READ_SYNC, WRITE_SYNC & co Christoph Hellwig
2010-06-21 10:04 ` Jens Axboe
2010-06-21 11:04 ` Christoph Hellwig
2010-06-21 18:56 ` Jens Axboe
2010-06-21 19:14 ` Christoph Hellwig
2010-06-21 19:16 ` Jens Axboe
2010-06-21 19:20 ` Christoph Hellwig
2010-06-21 21:36 ` Vivek Goyal
2010-06-23 10:01 ` Christoph Hellwig
2010-06-24 1:44 ` Vivek Goyal
2010-06-25 11:03 ` Christoph Hellwig
2010-06-26 3:35 ` Vivek Goyal
2010-06-26 10:05 ` Christoph Hellwig
2010-06-26 11:20 ` Jens Axboe
2010-06-26 11:56 ` Christoph Hellwig
2010-06-27 15:44 ` Jeff Moyer
2010-06-29 9:06 ` Corrado Zoccolo
2010-06-29 12:30 ` Vivek Goyal
2010-06-29 12:30 ` Vivek Goyal
2010-06-30 15:30 ` Corrado Zoccolo
2010-06-30 15:30 ` Corrado Zoccolo
2010-06-26 9:25 ` Nick Piggin
2010-06-26 9:27 ` Christoph Hellwig
2010-06-26 10:10 ` Nick Piggin
2010-06-26 10:16 ` Christoph Hellwig
2010-06-21 18:52 ` Jeff Moyer
2010-06-21 18:58 ` Jens Axboe
2010-06-21 19:08 ` Jeff Moyer
2010-06-23 9:26 ` Christoph Hellwig
2010-06-21 20:25 ` Vivek Goyal
2010-06-23 10:02 ` Christoph Hellwig [this message]
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