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List: linux-s390
Subject: Re: [PATCH 1/1] dasd: do not force use of deadline IO scheduler
From: Xose Vazquez Perez <xose.vazquez () gmail ! com>
Date: 2010-04-30 20:33:21
Message-ID: 4BDB3E91.8070505 () gmail ! com
[Download RAW message or body]
On 2008-03-04 8:52:10, Martin Schwidefsky wrote:
a bit old.
> On Mon, 2008-03-03 at 15:21 -0500, Josef 'Jeff' Sipek wrote:
>> Signed-off-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
>> ---
>> drivers/s390/block/dasd.c | 9 ---------
>> 1 files changed, 0 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
>> index ccf46c9..4d4f6ff 100644
>> --- a/drivers/s390/block/dasd.c
>> +++ b/drivers/s390/block/dasd.c
>> @@ -1946,21 +1946,12 @@ static void do_dasd_request(struct request_queue *queue)
>> */
>> static int dasd_alloc_queue(struct dasd_block *block)
>> {
>> - int rc;
>> -
>> block->request_queue = blk_init_queue(do_dasd_request,
>> &block->request_queue_lock);
>> if (block->request_queue == NULL)
>> return -ENOMEM;
>>
>> block->request_queue->queuedata = block;
>> -
>> - elevator_exit(block->request_queue->elevator);
>> - rc = elevator_init(block->request_queue, "deadline");
>> - if (rc) {
>> - blk_cleanup_queue(block->request_queue);
>> - return rc;
>> - }
>> return 0;
>> }
>
> Um, why? We have a reason to force the deadline scheduler, our
> performance test have shown that the deadline scheduler get the highest
> throughout out of the storage subsystems which are used with the
> machines.
Are there recent tests, cfq vs. deadline, with current kernels?
This FCP/SCSI test is a bit old(2005-03-16), and cfq vs. deadline shows no differences:
http://www.ibm.com/developerworks/linux/linux390/perf/tuning_res_dasd_ioScheduler.html
Any DASD test out there ?
-thanks-
--
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