From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
avi@scylladb.com, Dave Chinner <dchinner@redhat.com>
Subject: Re: [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio
Date: Thu, 21 Jan 2021 20:35:49 +1100 [thread overview]
Message-ID: <20210121093549.GC4662@dread.disaster.area> (raw)
In-Reply-To: <20210121085906.322712-12-hch@lst.de>
On Thu, Jan 21, 2021 at 09:59:06AM +0100, Christoph Hellwig wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Attempt shared locking for unaligned DIO, but only if the the
> underlying extent is already allocated and in written state. On
> failure, retry with the existing exclusive locking.
>
> Test case is fio randrw of 512 byte IOs using AIO and an iodepth of
> 32 IOs.
>
> Vanilla:
>
> READ: bw=4560KiB/s (4670kB/s), 4560KiB/s-4560KiB/s (4670kB/s-4670kB/s), io=134MiB (140MB), run=30001-30001msec
> WRITE: bw=4567KiB/s (4676kB/s), 4567KiB/s-4567KiB/s (4676kB/s-4676kB/s), io=134MiB (140MB), run=30001-30001msec
>
> Patched:
> READ: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1127MiB (1182MB), run=30002-30002msec
> WRITE: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1128MiB (1183MB), run=30002-30002msec
>
> That's an improvement from ~18k IOPS to a ~150k IOPS, which is
> about the IOPS limit of the VM block device setup I'm testing on.
>
> 4kB block IO comparison:
>
> READ: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8868MiB (9299MB), run=30002-30002msec
> WRITE: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8878MiB (9309MB), run=30002-30002msec
>
> Which is ~150k IOPS, same as what the test gets for sub-block
> AIO+DIO writes with this patch.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> [hch: rebased, split unaligned from nowait]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Looks good, minor nit:
> + /*
> + * For overwrite only I/O, we cannot convert unwritten extents without
> + * requiring sub-block zeroing. This can only be done under an
> + * exclusive IOLOCK, hence return -EAGAIN if this is not a written
> + * extent to tell the caller to try again.
> + */
> + if (flags & IOMAP_OVERWRITE_ONLY) {
> + error = -EAGAIN;
> + if (imap.br_state != XFS_EXT_NORM &&
> + ((offset & mp->m_blockmask) ||
> + ((offset + length) & mp->m_blockmask)))
> + goto out_unlock;
Why not use the ((offset | length) & mp->blockmask) form of
alignment checking here?
Other than that,
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2021-01-21 9:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 8:58 reduce sub-block DIO serialisation v3 Christoph Hellwig
2021-01-21 8:58 ` [PATCH 01/11] xfs: factor out a xfs_ilock_iocb helper Christoph Hellwig
2021-01-21 8:58 ` [PATCH 02/11] xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware Christoph Hellwig
2021-01-21 8:58 ` [PATCH 03/11] xfs: cleanup the read/write helper naming Christoph Hellwig
2021-01-21 8:58 ` [PATCH 04/11] xfs: remove the buffered I/O fallback assert Christoph Hellwig
2021-01-21 8:59 ` [PATCH 05/11] xfs: simplify the read/write tracepoints Christoph Hellwig
2021-01-21 8:59 ` [PATCH 06/11] xfs: improve the reflink_bounce_dio_write tracepoint Christoph Hellwig
2021-01-21 8:59 ` [PATCH 07/11] xfs: split unaligned DIO write code out Christoph Hellwig
2021-01-21 8:59 ` [PATCH 08/11] iomap: rename the flags variable in __iomap_dio_rw Christoph Hellwig
2021-01-21 8:59 ` [PATCH 09/11] iomap: pass a flags argument to iomap_dio_rw Christoph Hellwig
2021-01-21 9:30 ` Dave Chinner
2021-01-21 18:53 ` Darrick J. Wong
2021-01-21 8:59 ` [PATCH 10/11] iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag Christoph Hellwig
2021-01-21 9:32 ` Dave Chinner
2021-01-21 13:32 ` Brian Foster
2021-01-21 18:55 ` Darrick J. Wong
2021-01-21 8:59 ` [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio Christoph Hellwig
2021-01-21 9:35 ` Dave Chinner [this message]
2021-01-22 10:20 ` Christoph Hellwig
2021-01-21 13:33 ` Brian Foster
2021-01-21 19:01 ` Darrick J. Wong
-- strict thread matches above, loose matches on Subject: below --
2021-01-22 16:20 reduce sub-block DIO serialisation v4 Christoph Hellwig
2021-01-22 16:20 ` [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio Christoph Hellwig
2021-01-22 17:24 ` Darrick J. Wong
2021-01-18 19:35 reduce sub-block DIO serialisation v2 Christoph Hellwig
2021-01-18 19:35 ` [PATCH 11/11] xfs: reduce exclusive locking on unaligned dio Christoph Hellwig
2021-01-18 20:55 ` Dave Chinner
2021-01-20 16:36 ` Christoph Hellwig
2021-01-20 18:40 ` Darrick J. Wong
2021-01-20 18:44 ` Christoph Hellwig
2021-01-20 19:58 ` Darrick J. Wong
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