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From: Bart Van Assche <bvanassche@acm.org>
To: Christoph Hellwig <hch@lst.de>,
	James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>, Robert Elliot <Elliott@hp.com>,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: scsi-mq
Date: Fri, 13 Jun 2014 08:42:57 +0200	[thread overview]
Message-ID: <539A9D71.7020504@acm.org> (raw)
In-Reply-To: <1402580946-11470-1-git-send-email-hch@lst.de>

On 06/12/14 15:48, Christoph Hellwig wrote:
> The usage of blk-mq dramatically decreases CPU usage under all workloads going
> down from 100% CPU usage that the old setup can hit easily to usually less
> than 20% for maxing out storage subsystems with 512 byte reads and writes,
> and it allows to easily achieve millions of IOPS. Bart and Robert have
> helped with some very detailed measurements that they might be able to send
> in reply to this, although these usually involve significantly reworked low
> level drivers to avoid other bottle necks.

Thanks Christoph for writing up this excellent summary. In case anyone
is wondering which LLD changes Christoph is referring to: the tests I
ran myself were with an SRP initiator driver modified to use multiple
RDMA channels between initiator and target instead of a single channel.
I will post these changes for review on the linux-rdma mailing list as
soon as I have the time.

Bart.


  parent reply	other threads:[~2014-06-13  6:43 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-12 13:48 scsi-mq Christoph Hellwig
2014-06-12 13:48 ` [PATCH 01/14] sd: don't use rq->cmd_len before setting it up Christoph Hellwig
2014-06-12 13:48 ` [PATCH 02/14] scsi: split __scsi_queue_insert Christoph Hellwig
2014-06-12 13:48 ` [PATCH 03/14] scsi: centralize command re-queueing in scsi_dispatch_fn Christoph Hellwig
2014-06-12 13:48 ` [PATCH 04/14] scsi: set ->scsi_done before calling scsi_dispatch_cmd Christoph Hellwig
2014-06-12 13:48 ` [PATCH 05/14] scsi: push host_lock down into scsi_{host,target}_queue_ready Christoph Hellwig
2014-06-12 13:48 ` [PATCH 06/14] scsi: convert target_busy to an atomic_t Christoph Hellwig
2014-06-12 13:48 ` [PATCH 07/14] scsi: convert host_busy to atomic_t Christoph Hellwig
2014-06-12 13:49 ` [PATCH 08/14] scsi: convert device_busy " Christoph Hellwig
2014-06-12 13:49 ` [PATCH 09/14] scsi: fix the {host,target,device}_blocked counter mess Christoph Hellwig
2014-06-12 13:49 ` [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit Christoph Hellwig
2014-06-21 22:10   ` Elliott, Robert (Server Storage)
2014-06-23  7:09     ` Christoph Hellwig
2014-06-12 13:49 ` [PATCH 11/14] scsi: unwind blk_end_request_all and blk_end_request_err calls Christoph Hellwig
2014-06-12 13:49 ` [PATCH 12/14] scatterlist: allow chaining to preallocated chunks Christoph Hellwig
2014-06-12 13:49 ` [PATCH 13/14] scsi: add support for a blk-mq based I/O path Christoph Hellwig
2014-06-12 13:49 ` [PATCH 14/14] fnic: reject device resets without assigned tags for the blk-mq case Christoph Hellwig
2014-06-13  6:42 ` Bart Van Assche [this message]
2014-06-17 14:27 ` scsi-mq Bart Van Assche
2014-06-18  3:44   ` scsi-mq Jens Axboe
2014-06-18  7:09     ` scsi-mq Bart Van Assche
2014-06-21  0:52       ` scsi-mq Elliott, Robert (Server Storage)
2014-06-23  7:09         ` scsi-mq Christoph Hellwig
2014-06-19  0:58     ` scsi-mq Elliott, Robert (Server Storage)

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