From: Jens Axboe <jens.axboe@oracle.com>
To: "Raz Ben-Jehuda(caro)" <raziebe@gmail.com>
Cc: linux-aio@kvack.org, Linux Kernel <linux-kernel@vger.kernel.org>,
bcrl@kvack.org, zach.brown@oracle.com
Subject: Re: linux io_submit syscall duration
Date: Wed, 15 Nov 2006 08:47:21 +0100 [thread overview]
Message-ID: <20061115074720.GH23770@kernel.dk> (raw)
In-Reply-To: <5d96567b0611142339k23e78cc6u19b64052be5cd360@mail.gmail.com>
On Wed, Nov 15 2006, Raz Ben-Jehuda(caro) wrote:
> Bnejamin hello.
>
> My name is raz and i have encountered a problem with io_submit.
> The maximum duration of a single io_submit operation when
> heavily stressing the system with large number of big (1MB) ios,
> reaches several hundereds ms.
>
> I have been profiling it and it seems that the problem is the
> file->f_op->aio_read operation,
> a call that is made in fs/aio.c when coming from:
> sys_io_submit -->
> io_submit_one -->
> aio_run_iocb -->
> *retry
>
>
> The test is initiating several hundered 1MB IOs over a single block device.
>
> I understand that the assumption made was aio_read is asynchronous and no
> delay will occure, but isn't possible to do it in the workqueue context ?
This was discussed no more than a week ago on this list, please search the
archives for the thread.
--
Jens Axboe
next prev parent reply other threads:[~2006-11-15 7:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-15 7:39 linux io_submit syscall duration Raz Ben-Jehuda(caro)
2006-11-15 7:47 ` Jens Axboe [this message]
[not found] ` <5d96567b0611150143n1a7cc16dgea39fba748a2de7f@mail.gmail.com>
2006-11-15 9:47 ` Jens Axboe
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