zstd/contrib/pzstd

Parallel Zstandard (PZstandard)

Parallel Zstandard provides Zstandard format compatible compression and decompression that is able to utilize multiple cores. It breaks the input up into equal sized chunks and compresses each chunk independently into a Zstandard frame. It then concatenates the frames together to produce the final compressed output. Optionally, with the -p option, PZstandard will write a 12 byte header for each frame that is a skippable frame in the Zstandard format, which tells PZstandard the size of the next compressed frame. When -p is specified for compression, PZstandard can decompress the output in parallel.

Usage

Basic usage

pzstd input-file -o output-file -n num-threads [ -p ] -#   # Compression
pzstd -d input-file -o output-file -n num-threads          # Decompression

PZstandard also supports piping and fifo pipes

cat input-file | pzstd -n num-threads [ -p ] -# -c > /dev/null

For more options

pzstd --help

Benchmarks

As a reference, PZstandard and Pigz were compared on an Intel Core i7 @ 3.1 GHz, each using 4 threads, with the Silesia compression corpus.

Compression Speed vs Ratio with 4 Threads	Decompression Speed with 4 Threads

The test procedure was to run each of the following commands 2 times for each compression level, and take the minimum time.

time ./pzstd -# -n 4 -p -c silesia.tar > silesia.tar.zst
time ./pzstd -d -n 4    -c silesia.tar.zst > /dev/null

time pigz    -# -p 4 -k -c silesia.tar > silesia.tar.gz
time pigz    -d -p 4 -k -c silesia.tar.gz > /dev/null

PZstandard was tested using compression levels 1-19, and Pigz was tested using compression levels 1-9. Pigz cannot do parallel decompression, it simply does each of reading, decompression, and writing on separate threads.

Tests

Tests require that you have gtest installed. Modify GTEST_INC and GTEST_LIB in test/Makefile and utils/test/Makefile to work for your install of gtest. Then run make test in the contrib/pzstd directory.