From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Wang Jianchao <jianchao.wan9@gmail.com>
Cc: martin.petersen@oracle.com, jejb@linux.ibm.com,
linux-scsi@vger.kernel.org
Subject: Re: Discard performance regression after "scsi: sd: Remove LBPRZ dependency for discards"
Date: Wed, 07 Jul 2021 23:23:01 -0400 [thread overview]
Message-ID: <yq1pmvtbiy2.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <279cb008-4c92-0535-efdd-6e877bea7349@gmail.com> (Wang Jianchao's message of "Tue, 6 Jul 2021 11:11:25 +0800")
Wang,
> We have a sata ssd with following parameters,
>
> max_ws_blocks = 0
> max_unmap_blocks = 262143
> lbprz = 1
> lbpu = 1
> unmap_limit_for_ws = 0
The device is explicitly asking for us to use UNMAP so the older kernel
choosing WRITE SAME(16) was not correct.
I have been working on an update to the discard/zeroing heuristics that
I'll post when 5.15 opens next week. But based on what's reported it by
your device we would still choose UNMAP for discards. LBPRZ only affects
which command we use for zeroing.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2021-07-08 3:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-06 3:11 Discard performance regression after "scsi: sd: Remove LBPRZ dependency for discards" Wang Jianchao
2021-07-08 3:23 ` Martin K. Petersen [this message]
2021-07-08 6:05 ` Wang Jianchao
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