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| author | Denis Plotnikov | 2020-05-07 10:25:20 +0200 |
|---|---|---|
| committer | Max Reitz | 2020-05-13 14:20:31 +0200 |
| commit | d298ac10add95e2b7f8850332f3b755c8a23d925 (patch) | |
| tree | bf193bc9436246156677dd11c79a3b93fc13bfac /qapi/block-core.json | |
| parent | qcow2: rework the cluster compression routine (diff) | |
| download | qemu-d298ac10add95e2b7f8850332f3b755c8a23d925.tar.gz qemu-d298ac10add95e2b7f8850332f3b755c8a23d925.tar.xz qemu-d298ac10add95e2b7f8850332f3b755c8a23d925.zip | |
qcow2: add zstd cluster compression
zstd significantly reduces cluster compression time.
It provides better compression performance maintaining
the same level of the compression ratio in comparison with
zlib, which, at the moment, is the only compression
method available.
The performance test results:
Test compresses and decompresses qemu qcow2 image with just
installed rhel-7.6 guest.
Image cluster size: 64K. Image on disk size: 2.2G
The test was conducted with brd disk to reduce the influence
of disk subsystem to the test results.
The results is given in seconds.
compress cmd:
time ./qemu-img convert -O qcow2 -c -o compression_type=[zlib|zstd]
src.img [zlib|zstd]_compressed.img
decompress cmd
time ./qemu-img convert -O qcow2
[zlib|zstd]_compressed.img uncompressed.img
compression decompression
zlib zstd zlib zstd
------------------------------------------------------------
real 65.5 16.3 (-75 %) 1.9 1.6 (-16 %)
user 65.0 15.8 5.3 2.5
sys 3.3 0.2 2.0 2.0
Both ZLIB and ZSTD gave the same compression ratio: 1.57
compressed image size in both cases: 1.4G
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
QAPI part:
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200507082521.29210-4-dplotnikov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'qapi/block-core.json')
| -rw-r--r-- | qapi/block-core.json | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/qapi/block-core.json b/qapi/block-core.json index 1522e2983f..6fbacddab2 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4293,11 +4293,12 @@ # Compression type used in qcow2 image file # # @zlib: zlib compression, see <http://zlib.net/> +# @zstd: zstd compression, see <http://github.com/facebook/zstd> # # Since: 5.1 ## { 'enum': 'Qcow2CompressionType', - 'data': [ 'zlib' ] } + 'data': [ 'zlib', { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] } ## # @BlockdevCreateOptionsQcow2: |