| commit | b3cf1c7cf8714af96def49668a267fa4075242ca | |
| author | Alberto Garcia <berto@igalia.com> | |
| Mon, 19 Jun 2017 13:40:06 +0000 (19 16:40 +0300) | ||
| committer | Kevin Wolf <kwolf@redhat.com> | |
| Mon, 26 Jun 2017 12:51:13 +0000 (26 14:51 +0200) | ||
| tree | 786ca93bbde6ffe9802f723c68faf69faae93828 | treesnapshot (tar.gz zip) |
| parent | 672f0f2c4b5ee521f5ea06eadaacf8dfa99474f4 | commitdiff |
qcow2: Allow reading both COW regions with only one request
Reading both COW regions requires two separate requests, but it's
perfectly possible to merge them and perform only one. This generally
improves performance, particularly on rotating disk drives. The
downside is that the data in the middle region is read but discarded.
This patch takes a conservative approach and only merges reads when
the size of the middle region is <= 16KB.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reading both COW regions requires two separate requests, but it's
perfectly possible to merge them and perform only one. This generally
improves performance, particularly on rotating disk drives. The
downside is that the data in the middle region is read but discarded.
This patch takes a conservative approach and only merges reads when
the size of the middle region is <= 16KB.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| block/qcow2-cluster.c | diffblobblamehistory |