Messages in this thread | | | Date | Wed, 15 Nov 2006 08:47:21 +0100 | From | Jens Axboe <> | Subject | Re: linux io_submit syscall duration |
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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 ?
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-- Jens Axboe
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