From: Damien Le Moal <Damien.LeMoal@wdc.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Bob Liu <bob.liu@oracle.com>,
"dm-devel@redhat.com" <dm-devel@redhat.com>,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCHv5 00/14] dm-zoned: metadata version 2
Date: Thu, 14 May 2020 00:55:10 +0000 [thread overview]
Message-ID: <BY5PR04MB6900B82F4BEE1B13B239D93EE7BC0@BY5PR04MB6900.namprd04.prod.outlook.com> (raw)
In-Reply-To: yq13683z7sj.fsf@oracle.com
On 2020/05/14 9:22, Martin K. Petersen wrote:
>
> Damien,
>
>> Any idea why the io_opt limit is not set to the physical block size
>> when the drive does not report an optimal transfer length ? Would it
>> be bad to set that value instead of leaving it to 0 ?
>
> The original intent was that io_opt was a weak heuristic for something
> being a RAID device. Regular disk drives didn't report it. These days
> that distinction probably isn't relevant.
>
> However, before we entertain departing from the historic io_opt
> behavior, I am a bit puzzled by the fact that you have a device that
> reports io_opt as 512 bytes. What kind of device performs best when each
> I/O is limited to a single logical block?
>
Indeed. It is an NVMe M.2 consumer grade SSD. Nothing fancy. If you look at
nvme/host/core.c nvme_update_disk_info(), you will see that io_opt is set to the
block size... This is probably abusing this limit. So I guess the most elegant
fix may be to have nvme stop doing that ?
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2020-05-14 0:55 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 9:03 [PATCHv5 00/14] dm-zoned: metadata version 2 Hannes Reinecke
2020-05-08 9:03 ` [PATCH 01/14] dm-zoned: add 'status' and 'message' callbacks Hannes Reinecke
2020-05-08 16:29 ` Mike Snitzer
2020-05-08 18:25 ` Hannes Reinecke
2020-05-08 21:00 ` Mike Snitzer
2020-05-08 9:03 ` [PATCH 02/14] dm-zoned: store zone id within the zone structure and kill dmz_id() Hannes Reinecke
2020-05-08 9:03 ` [PATCH 03/14] dm-zoned: use array for superblock zones Hannes Reinecke
2020-05-08 9:03 ` [PATCH 04/14] dm-zoned: store device in struct dmz_sb Hannes Reinecke
2020-05-08 9:03 ` [PATCH 05/14] dm-zoned: move fields from struct dmz_dev to dmz_metadata Hannes Reinecke
2020-05-08 9:03 ` [PATCH 06/14] dm-zoned: introduce dmz_metadata_label() to format device name Hannes Reinecke
2020-05-08 9:03 ` [PATCH 07/14] dm-zoned: Introduce dmz_dev_is_dying() and dmz_check_dev() Hannes Reinecke
2020-05-08 9:03 ` [PATCH 08/14] dm-zoned: remove 'dev' argument from reclaim Hannes Reinecke
2020-05-08 9:03 ` [PATCH 09/14] dm-zoned: replace 'target' pointer in the bio context Hannes Reinecke
2020-05-08 9:03 ` [PATCH 10/14] dm-zoned: use dmz_zone_to_dev() when handling metadata I/O Hannes Reinecke
2020-05-08 9:03 ` [PATCH 11/14] dm-zoned: add metadata logging functions Hannes Reinecke
2020-05-08 9:03 ` [PATCH 12/14] dm-zoned: Reduce logging output on startup Hannes Reinecke
2020-05-11 2:48 ` Damien Le Moal
2020-05-08 9:03 ` [PATCH 13/14] dm-zoned: ignore metadata zone in dmz_alloc_zone() Hannes Reinecke
2020-05-08 9:03 ` [PATCH 14/14] dm-zoned: metadata version 2 Hannes Reinecke
2020-05-08 16:38 ` Mike Snitzer
2020-05-11 3:00 ` Damien Le Moal
2020-05-11 2:46 ` [PATCHv5 00/14] " Damien Le Moal
2020-05-11 6:31 ` Hannes Reinecke
2020-05-11 6:41 ` Damien Le Moal
2020-05-11 6:55 ` Damien Le Moal
2020-05-12 16:49 ` Mike Snitzer
2020-05-11 10:55 ` Damien Le Moal
2020-05-11 11:19 ` Hannes Reinecke
2020-05-11 11:25 ` Damien Le Moal
2020-05-11 11:24 ` Hannes Reinecke
2020-05-11 11:46 ` Damien Le Moal
2020-05-11 13:23 ` Damien Le Moal
2020-05-13 23:56 ` Damien Le Moal
2020-05-14 0:20 ` Martin K. Petersen
2020-05-14 0:55 ` Damien Le Moal [this message]
2020-05-14 2:19 ` Martin K. Petersen
2020-05-14 2:22 ` Damien Le Moal
2020-05-14 5:56 ` Hannes Reinecke
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