Re: [Qemu-devel] [PATCH 0/3] migration: add sztd compression

[Denis Plotnikov]

ping!

On 26.02.2019 16:15, Denis Plotnikov wrote:
> zstd date compression algorithm shows better performance on data compression.
> It might be useful to employ the algorithm in VM migration to reduce CPU 
> usage.
> A user will be able to choose between those algorithms, therefor compress-type
> migration parameter is added.
> 
> Here are some results of performance comparison zstd vs gzip:
> 
> host: i7-4790 8xCPU @ 3.60GHz, 16G RAM
> migration to the same host
> VM: 2xVCPU, 8G RAM total
> 5G RAM used, memory populated with postgreqsl data
> produced by pgbench performance benchmark
> 
> 
> Threads: 1 compress – 1 decompress
> 
> zstd provides slightly less compression ratio with almost the same
> CPU usage but copes with RAM  compression roghly 2 times faster
> 
> compression type              zlib       |      zstd
> ---------------------------------------------------------
> compression level          1       5     |   1       5
> compression ratio          6.92    7.05  |   6.69    6.89
> cpu idle, %                82      83    |   86      80
> time, sec                  49      71    |   26      31
> time diff to zlib, sec                      -25     -41
> 
> 
> Threads: 8 compress – 2 decompress
> 
> zstd provides the same migration time with less cpu consumption
> 
> compression type         none  |        gzip(zlib)    |          zstd
> ------------------------------------------------------------------------------
> compression level        -     |  1      5       9    |   1       5       15
> compression ratio        -     |  6.94   6.99    7.14 |   6.64    6.89    6.93
> time, sec                154   |  22     23      27   |   23      23      25
> cpu idle, %              99    |  45     30      12   |   70      52      23
> cpu idle diff to zlib          |                      |  -25%    -22%    -11%
> 
> 
> Denis Plotnikov (3):
>    migration: rework compression code for adding more data compressors
>    hmp: add compress-type parameter to migration parameters
>    migration: add zstd compression
> 
>   configure             |  26 ++++
>   hmp.c                 |   8 ++
>   migration/migration.c |  45 ++++++-
>   migration/migration.h |   1 +
>   migration/qemu-file.c |  39 ++----
>   migration/qemu-file.h |  18 ++-
>   migration/ram.c       | 291 ++++++++++++++++++++++++++++++++++--------
>   qapi/migration.json   |  26 +++-
>   8 files changed, 369 insertions(+), 85 deletions(-)
> 

-- 
Best,
Denis