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From: Zach Brown <zach.brown@oracle.com>
To: Xavier Roche <roche+kml2@exalead.com>
Cc: linux-kernel@vger.kernel.org, linux-aio <linux-aio@kvack.org>
Subject: Re: io_submit() taking a long time to return ?
Date: Thu, 13 Jul 2006 08:44:48 -0700	[thread overview]
Message-ID: <44B66A70.90502@oracle.com> (raw)
In-Reply-To: <44B5ED5F.1040606@exalead.com>


> By reading the aio documentation, we expected the io_submit call to
> always return immediately,

Sadly, that isn't guaranteed.

> but in our preliminary tests we noticed that
> sometimes this call can take a long time (more than 10 ms, even
> sometimes more than 30 ms !!).

If I had to guess I'd suspect that these delays are due to sync block
mapping lookups in the submit path.  Do these tend to show up the first
time you read a file?

- z

  reply	other threads:[~2006-07-13 15:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-13  6:51 io_submit() taking a long time to return ? Xavier Roche
2006-07-13 15:44 ` Zach Brown [this message]
2006-07-13 16:32   ` Raz Ben-Jehuda(caro)
2006-07-13 16:48     ` Zach Brown

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