04.03.2020 16:35, Denis Plotnikov wrote:
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 <[email protected]> QAPI part: Acked-by: Markus Armbruster <[email protected]> Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Looks a bit like I've reviewed only QAPI part, when actually my r-b is for full patch... May be Acked-by: Markus Armbruster <[email protected]> [QAPI part] Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]> -- Best regards, Vladimir
