From: Wang Jianchao <jianchao.wan9@gmail.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: jejb@linux.ibm.com, linux-scsi@vger.kernel.org
Subject: Re: Discard performance regression after "scsi: sd: Remove LBPRZ dependency for discards"
Date: Thu, 8 Jul 2021 14:05:49 +0800 [thread overview]
Message-ID: <f1331877-5221-5aaa-d896-ff487dbdf2d6@gmail.com> (raw)
In-Reply-To: <yq1pmvtbiy2.fsf@ca-mkp.ca.oracle.com>
Thanks so much for your comment, Martin ;)
That's really helpful.
Jianchao
On 2021/7/8 11:23 AM, Martin K. Petersen wrote:
>
> 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.
>
prev parent reply other threads:[~2021-07-08 6:05 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
2021-07-08 6:05 ` Wang Jianchao [this message]
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