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Date: Thu, 13 Jul 2006 08:44:48 -0700
From: Zach Brown <zach.brown@oracle.com>
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To: Xavier Roche <roche+kml2@exalead.com>
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Subject: Re: io_submit() taking a long time to return ?
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> 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