From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: david@fromorbit.com, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 3/4] xfs: speed up rmap lookups by using non-overlapped lookups when possible
Date: Thu, 28 Apr 2022 05:44:44 -0700 [thread overview]
Message-ID: <YmqMPHXhXoePYU6X@infradead.org> (raw)
In-Reply-To: <165102070261.3922526.1584531429524068308.stgit@magnolia>
On Tue, Apr 26, 2022 at 05:51:42PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Reverse mapping on a reflink-capable filesystem has some pretty high
> overhead when performing file operations. This is because the rmap
> records for logically and physically adjacent extents might not be
> adjacent in the rmap index due to data block sharing. As a result, we
> use expensive overlapped-interval btree search, which walks every record
> that overlaps with the supplied key in the hopes of finding the record.
>
> However, profiling data shows that when the index contains a record that
> is an exact match for a query key, the non-overlapped btree search
> function can find the record much faster than the overlapped version.
> Try the non-overlapped lookup first, which will make scrub run much
> faster.
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2022-04-28 12:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 0:51 [PATCHSET v2 0/4] xfs: fix rmap inefficiencies Darrick J. Wong
2022-04-27 0:51 ` [PATCH 1/4] xfs: capture buffer ops in the xfs_buf tracepoints Darrick J. Wong
2022-04-27 0:51 ` [PATCH 2/4] xfs: simplify xfs_rmap_lookup_le call sites Darrick J. Wong
2022-04-27 0:51 ` [PATCH 3/4] xfs: speed up rmap lookups by using non-overlapped lookups when possible Darrick J. Wong
2022-04-27 4:19 ` Dave Chinner
2022-04-28 12:44 ` Christoph Hellwig [this message]
2022-04-27 0:51 ` [PATCH 4/4] xfs: speed up write operations " Darrick J. Wong
2022-04-27 4:22 ` Dave Chinner
2022-04-28 12:45 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2022-04-14 22:53 [PATCHSET 0/4] xfs: fix rmap inefficiencies Darrick J. Wong
2022-04-14 22:54 ` [PATCH 3/4] xfs: speed up rmap lookups by using non-overlapped lookups when possible Darrick J. Wong
2022-04-22 21:43 ` Dave Chinner
2022-04-25 18:35 ` Darrick J. Wong
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