diff --git a/programs/README.md b/programs/README.md index a097cdac7..2f212f68a 100644 --- a/programs/README.md +++ b/programs/README.md @@ -142,23 +142,34 @@ Advanced arguments : -q : suppress warnings; specify twice to suppress errors too -c : force write to standard output, even if it is the console -l : print information about zstd compressed files +--exclude-compressed: only compress files that are not previously compressed --ultra : enable levels beyond 19, up to 22 (requires more memory) ---long : enable long distance matching (requires more memory) +--long[=#]: enable long distance matching with given window log (default: 27) +--fast[=#]: switch to very fast compression levels (default: 1) +--adapt : dynamically adapt compression level to I/O conditions +--stream-size=# : optimize compression parameters for streaming input of given number of bytes +--size-hint=# optimize compression parameters for streaming input of approximately this size +--target-compressed-block-size=# : make compressed block near targeted size + -T# : spawns # compression threads (default: 1, 0==# cores) + -B# : select size of each job (default: 0==automatic) +--rsyncable : compress using a rsync-friendly method (-B sets block size) --no-dictID : don't write dictID into header (dictionary compression) --[no-]check : integrity check (default: enabled) +--[no-]compress-literals : force (un)compressed literals -r : operate recursively on directories +--output-dir-flat[=directory]: all resulting files stored into `directory`. +--format=zstd : compress files to the .zst format (default) --format=gzip : compress files to the .gz format ---format=xz : compress files to the .xz format ---format=lzma : compress files to the .lzma format --test : test compressed file integrity --[no-]sparse : sparse mode (default: disabled) -M# : Set a memory usage limit for decompression +--no-progress : do not display the progress bar -- : All arguments after "--" are treated as files Dictionary builder : --train ## : create a dictionary from a training set of files --train-cover[=k=#,d=#,steps=#,split=#,shrink[=#]] : use the cover algorithm with optional args ---train-fastcover[=k=#,d=#,f=#,steps=#,split=#,shrink[=#],accel=#] : use the fastcover algorithm with optional args +--train-fastcover[=k=#,d=#,f=#,steps=#,split=#,accel=#,shrink[=#]] : use the fast cover algorithm with optional args --train-legacy[=s=#] : use the legacy algorithm with selectivity (default: 9) -o file : `file` is dictionary name (default: dictionary) --maxdict=# : limit dictionary to specified size (default: 112640) @@ -208,12 +219,12 @@ Compression Speed vs Ratio | Decompression Speed | Method | Compression ratio | Compression speed | Decompression speed | |:-------|------------------:|-------------------------:|---------------------------:| -| `zstd -1` | `5.065` | `284.8 MB/s` | `759.3 MB/s` | +| `zstd -1` | `5.065` | `284.8 MB/s` | `759.3 MB/s` | | `zstd -5` | `5.826` | `124.9 MB/s` | `674.0 MB/s` | | `zstd -10` | `6.504` | `29.5 MB/s` | `771.3 MB/s` | | `zstd -1 --long` | `17.426` | `220.6 MB/s` | `1638.4 MB/s` | -| `zstd -5 --long` | `19.661` | `165.5 MB/s` | `1530.6 MB/s`| -| `zstd -10 --long`| `21.949` | `75.6 MB/s` | `1632.6 MB/s`| +| `zstd -5 --long` | `19.661` | `165.5 MB/s` | `1530.6 MB/s` | +| `zstd -10 --long`| `21.949` | `75.6 MB/s` | `1632.6 MB/s` | On this file, the compression ratio improves significantly with minimal impact on compression speed, and the decompression speed doubles.