From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: John Pittman <jpittman@redhat.com>
Cc: axboe@kernel.dk, djeffery@redhat.com, loberman@redhat.com,
emilne@redhat.com, minlei@redhat.com,
linux-block@vger.kernel.org, ming.lei@redhat.com,
Mike Snitzer <msnitzer@redhat.com>
Subject: Re: [PATCH] block: set reasonable default for discard max
Date: Tue, 20 Jun 2023 11:06:21 -0400 [thread overview]
Message-ID: <yq1edm6rxgy.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <CA+RJvhx0G7cLeQ1krpD8Noc7iZYcC4bMaVNzVsrcOrXE=yCdNQ@mail.gmail.com> (John Pittman's message of "Mon, 19 Jun 2023 12:02:36 -0400")
John,
> 1) Set a 64M limit as you've suggested in the past. It seems more
> prudent to tune the value upward for the few devices that can actually
> handle a 2TiB discard rather than tune downward for the large
> majority.
This makes the assumption that smaller always equals faster. However,
some devices track allocations in very large units. And as a result,
sending smaller discards will result in *slower* performance for those
devices. In addition, for doings things like the full block device sweep
we do during mkfs, it is often imperative that we issue large sequential
ranges.
Please provide the VPD pages from the device in question.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2023-06-20 15:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 18:08 [PATCH] block: set reasonable default for discard max John Pittman
2023-06-09 18:46 ` Martin K. Petersen
2023-06-10 0:22 ` John Pittman
2023-06-10 22:52 ` Chaitanya Kulkarni
2023-06-13 0:55 ` Martin K. Petersen
2023-06-13 11:23 ` Ewan Milne
2023-06-13 1:37 ` Ming Lei
2023-06-19 16:02 ` John Pittman
2023-06-20 15:06 ` Martin K. Petersen [this message]
2023-07-14 17:15 ` John Pittman
2023-07-20 1:58 ` Martin K. Petersen
2023-07-20 14:43 ` John Pittman
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