From: Mike Christie <michael.christie@oracle.com>
To: martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
target-devel@vger.kernel.org
Subject: [PATCH 0/5] scsi: target: Allow userspace to config cmd submission
Date: Mon, 10 Jul 2023 16:44:37 -0500 [thread overview]
Message-ID: <20230710214442.6718-1-michael.christie@oracle.com> (raw)
The following patches were made over Linus's tree but apply over Martin's
branches. They allow userspace to configure how fabric drivers submit cmds
to backend drivers.
Right now loop and vhost use a worker thread, and the other drivers submit
from the contexts they receive/process the cmd from. For multiple LUN
cases where the target can queue more cmds than the backend can handle
then defering to a worker thread is safest because the backend driver can
block when doing things like waiting for a free request/tag. For cases
where the backend devices can queue everything the target sends, then
there is no need to defer to a workqueue and you can see a perf boost of
up to 26% for small IO workloads. For a nvme device and vhost-scsi I can
see with 4K IOs:
fio jobs 1 2 4 8 10
--------------------------------------------------
workqueue
submit 94K 190K 394K 770K 890K
direct
submit 128K 252K 488K 950K -
next reply other threads:[~2023-07-10 21:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-10 21:44 Mike Christie [this message]
2023-07-10 21:44 ` [PATCH 1/5] scsi: target: Make write_pending_must_be_called a bit field Mike Christie
2023-07-10 21:44 ` [PATCH 2/5] scsi: target: Have drivers report if they support direct submissions Mike Christie
2023-07-10 21:44 ` [PATCH 3/5] scsi: target: Allow userspace to request " Mike Christie
2023-07-10 21:44 ` [PATCH 4/5] scsi: target: Unexport target_queue_submission Mike Christie
2023-07-10 21:44 ` [PATCH 5/5] scsi: target: Export fabric driver direct submit settings Mike Christie
2023-07-13 13:06 ` Konstantin Shelekhin
2023-07-13 15:50 ` Mike Christie
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