From: Hannes Reinecke <hare@suse.de>
To: Luis Chamberlain <mcgrof@kernel.org>,
willy@infradead.org, hch@lst.de, david@fromorbit.com,
djwong@kernel.org
Cc: john.g.garry@oracle.com, ritesh.list@gmail.com,
kbusch@kernel.org, linux-fsdevel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-mm@kvack.org,
linux-block@vger.kernel.org, gost.dev@samsung.com,
p.raghav@samsung.com, da.gomez@samsung.com,
kernel@pankajraghav.com
Subject: Re: [RFC 8/8] bdev: use bdev_io_min() for statx block size
Date: Wed, 13 Nov 2024 10:59:06 +0100 [thread overview]
Message-ID: <25631870-851f-44bd-b214-8d7d451cb8a5@suse.de> (raw)
In-Reply-To: <20241113094727.1497722-9-mcgrof@kernel.org>
On 11/13/24 10:47, Luis Chamberlain wrote:
> You can use lsblk to query for a block device block device block size:
>
> lsblk -o MIN-IO /dev/nvme0n1
> MIN-IO
> 4096
>
> The min-io is the minimum IO the block device prefers for optimal
> performance. In turn we map this to the block device block size.
> The current block size exposed even for block devices with an
> LBA format of 16k is 4k. Likewise devices which support 4k LBA format
> but have a larger Indirection Unit of 16k have an exposed block size
> of 4k.
>
> This incurs read-modify-writes on direct IO against devices with a
> min-io larger than the page size. To fix this, use the block device
> min io, which is the minimal optimal IO the device prefers.
>
> With this we now get:
>
> lsblk -o MIN-IO /dev/nvme0n1
> MIN-IO
> 16384
>
> And so userspace gets the appropriate information it needs for optimal
> performance. This is verified with blkalgn against mkfs against a
> device with LBA format of 4k but an NPWG of 16k (min io size)
>
> mkfs.xfs -f -b size=16k /dev/nvme3n1
> blkalgn -d nvme3n1 --ops Write
>
> Block size : count distribution
> 0 -> 1 : 0 | |
> 2 -> 3 : 0 | |
> 4 -> 7 : 0 | |
> 8 -> 15 : 0 | |
> 16 -> 31 : 0 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 0 | |
> 128 -> 255 : 0 | |
> 256 -> 511 : 0 | |
> 512 -> 1023 : 0 | |
> 1024 -> 2047 : 0 | |
> 2048 -> 4095 : 0 | |
> 4096 -> 8191 : 0 | |
> 8192 -> 16383 : 0 | |
> 16384 -> 32767 : 66 |****************************************|
> 32768 -> 65535 : 0 | |
> 65536 -> 131071 : 0 | |
> 131072 -> 262143 : 2 |* |
> Block size: 14 - 66
> Block size: 17 - 2
>
> Algn size : count distribution
> 0 -> 1 : 0 | |
> 2 -> 3 : 0 | |
> 4 -> 7 : 0 | |
> 8 -> 15 : 0 | |
> 16 -> 31 : 0 | |
> 32 -> 63 : 0 | |
> 64 -> 127 : 0 | |
> 128 -> 255 : 0 | |
> 256 -> 511 : 0 | |
> 512 -> 1023 : 0 | |
> 1024 -> 2047 : 0 | |
> 2048 -> 4095 : 0 | |
> 4096 -> 8191 : 0 | |
> 8192 -> 16383 : 0 | |
> 16384 -> 32767 : 66 |****************************************|
> 32768 -> 65535 : 0 | |
> 65536 -> 131071 : 0 | |
> 131072 -> 262143 : 2 |* |
> Algn size: 14 - 66
> Algn size: 17 - 2
>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
> block/bdev.c | 1 +
> fs/stat.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
next prev parent reply other threads:[~2024-11-13 9:59 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-13 9:47 [RFC 0/8] enable bs > ps for block devices Luis Chamberlain
2024-11-13 9:47 ` [RFC 1/8] fs/mpage: use blocks_per_folio instead of blocks_per_page Luis Chamberlain
2024-11-13 9:47 ` [RFC 2/8] fs/mpage: avoid negative shift for large blocksize Luis Chamberlain
2024-11-13 14:06 ` Matthew Wilcox
2024-11-14 13:47 ` Hannes Reinecke
2024-11-13 9:47 ` [RFC 3/8] fs/buffer: restart block_read_full_folio() to avoid array overflow Luis Chamberlain
2024-11-13 18:50 ` Matthew Wilcox
2024-11-13 9:47 ` [RFC 4/8] fs/buffer fs/mpage: remove large folio restriction Luis Chamberlain
2024-11-13 9:55 ` Hannes Reinecke
2024-11-13 9:47 ` [RFC 5/8] block/bdev: enable large folio support for large logical block sizes Luis Chamberlain
2024-11-13 9:47 ` [RFC 6/8] block/bdev: lift block size restrictions and use common definition Luis Chamberlain
2024-11-13 9:57 ` Hannes Reinecke
2024-11-13 14:14 ` Matthew Wilcox
2024-11-18 9:18 ` John Garry
2024-11-13 9:47 ` [RFC 7/8] nvme: remove superfluous block size check Luis Chamberlain
2024-11-13 9:57 ` Hannes Reinecke
2024-11-13 9:47 ` [RFC 8/8] bdev: use bdev_io_min() for statx block size Luis Chamberlain
2024-11-13 9:59 ` Hannes Reinecke [this message]
2024-11-18 7:08 ` Christoph Hellwig
2024-11-18 21:16 ` Luis Chamberlain
2024-11-19 6:08 ` Christoph Hellwig
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