From: Jens Axboe <axboe@fb.com>
To: axboe@kernel.dk, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org
Cc: hch@lst.de
Subject: [PATCH RFC] mpt2/mpt3sas lock reduction for scsi-mq
Date: Fri, 3 Apr 2015 09:58:16 -0600 [thread overview]
Message-ID: <1428076703-31014-1-git-send-email-axboe@fb.com> (raw)
Hi,
There's some "low" hanging fruit in the lsi mpt drivers for further
lock reduction, when running in scsi-mq mode. For each IO, they have
to lock/{get,put}/unlock a scsiio_tracker structure that is associated
with the IO. In scsi-mq mode, we can ask for some payload for each
command, so we don't have to store and manage this tracker structure
separately.
In some testing on mpt2sas, this roughly cuts the locking time in half
at just 100K IOPS. Compared to scsi-mq not being enabled, the locking
time with the patchset is reduced from ~47% to just ~4%.
--
Jens Axboe
next reply other threads:[~2015-04-03 15:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-03 15:58 Jens Axboe [this message]
2015-04-03 15:58 ` [PATCH 1/7] blk-mq: allow the callback to blk_mq_tag_busy_iter() to stop looping Jens Axboe
2015-04-03 15:58 ` [PATCH 2/7] blk-mq: add helper to iterate all busy tags on all hardware queues Jens Axboe
2015-04-03 15:58 ` [PATCH 3/7] scsi: add scsi-mq helpers to retrieve pdu and check started state Jens Axboe
2015-04-05 15:39 ` Christoph Hellwig
2015-04-03 15:58 ` [PATCH 4/7] scsi: add scsi-mq helper for iterating over busy commands Jens Axboe
2015-04-05 15:40 ` Christoph Hellwig
2015-04-03 15:58 ` [PATCH 5/7] scsi: add host template init/exit_command hooks Jens Axboe
2015-04-05 15:40 ` Christoph Hellwig
2015-04-03 15:58 ` [PATCH 6/7] mpt2sas: store scsi io tracker data in the scsi command / request Jens Axboe
2015-04-05 16:03 ` Christoph Hellwig
2015-04-07 16:13 ` Jens Axboe
2015-04-07 16:18 ` Christoph Hellwig
2015-04-07 19:22 ` Jens Axboe
2015-04-03 15:58 ` [PATCH 7/7] mpt3sas: " Jens Axboe
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