From: Fabio Checconi <fchecconi@gmail.com>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: Matthew <jackdachef@gmail.com>,
Daniel J Blueman <daniel.blueman@gmail.com>,
Kasper Sandberg <lkml@metanurb.dk>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: performance "regression" in cfq compared to anticipatory, deadline and noop
Date: Fri, 16 May 2008 09:46:28 +0200 [thread overview]
Message-ID: <20080516074628.GA17802@gandalf.sssup.it> (raw)
In-Reply-To: <20080516064002.GL16217@kernel.dk>
> From: Jens Axboe <jens.axboe@oracle.com>
> Date: Fri, May 16, 2008 08:40:03AM +0200
>
...
> I think we can improve this further without getting too involved. If a
> 2nd request is seen in cfq_rq_enqueued(), then DO schedule a dispatch
> since this likely means that we wont be doing more merges on the first
> one.
>
But isn't there the risk that even the second request would be
dispatched, while it still could have grown?
Moreover I am still unsure about how to handle (and if it's worth
handling) the case in which we restart queueing after an empty
dispatch round due to idling, as it would still have the same
problem.
(Also anticipatory doesn't handle this case too well.)
next prev parent reply other threads:[~2008-05-16 7:40 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-11 13:14 Daniel J Blueman
2008-05-11 14:02 ` Kasper Sandberg
2008-05-13 12:20 ` Jens Axboe
2008-05-13 12:58 ` Matthew
2008-05-13 13:05 ` Jens Axboe
[not found] ` <e85b9d30805130842p3a34305l4ab1e7926e4b0dba@mail.gmail.com>
2008-05-13 18:03 ` Jens Axboe
2008-05-13 18:40 ` Jens Axboe
2008-05-13 19:23 ` Matthew
2008-05-13 19:30 ` Jens Axboe
2008-05-14 8:05 ` Daniel J Blueman
2008-05-14 8:26 ` Jens Axboe
2008-05-14 20:52 ` Daniel J Blueman
2008-05-14 21:37 ` Matthew
2008-05-15 7:01 ` Jens Axboe
2008-05-15 12:21 ` Fabio Checconi
2008-05-16 6:40 ` Jens Axboe
2008-05-16 7:46 ` Fabio Checconi [this message]
2008-05-16 7:49 ` Jens Axboe
2008-05-16 7:57 ` Jens Axboe
2008-05-16 8:53 ` Daniel J Blueman
2008-05-16 8:57 ` Jens Axboe
2008-05-16 15:23 ` Matthew
2008-05-16 18:39 ` Fabio Checconi
2008-08-24 20:24 ` Daniel J Blueman
2008-08-25 20:29 ` Fabio Checconi
2008-08-25 15:39 ` Daniel J Blueman
2008-08-25 17:06 ` Fabio Checconi
2008-12-09 15:14 ` Daniel J Blueman
[not found] ` <e85b9d30805140332r3311b2d6r6831d37421ced757@mail.gmail.com>
[not found] ` <e85b9d30805140334q69cb5eacued9a719414e73d53@mail.gmail.com>
[not found] ` <20080514103956.GD16217@kernel.dk>
[not found] ` <e85b9d30805141239g5df9abc6i666b1f621d632b44@mail.gmail.com>
[not found] ` <e85b9d30805161549o7c8f065do24b6567e2ade0afa@mail.gmail.com>
2008-05-19 10:39 ` Matthew
2008-05-13 13:51 ` Kasper Sandberg
2008-05-14 0:33 ` Kasper Sandberg
-- strict thread matches above, loose matches on Subject: below --
2008-05-10 19:18 Matthew
[not found] ` <20080510200053.GA78555@gandalf.sssup.it>
2008-05-10 20:39 ` Matthew
2008-05-10 21:56 ` Fabio Checconi
2008-05-11 0:00 ` Aaron Carroll
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