1 files changed, 55 insertions, 18 deletions
diff --git a/programs/zstd.1 b/programs/zstd.1
index 8e9e83745a0f..674f89841ce8 100644
--- a/programs/zstd.1
+++ b/programs/zstd.1
@@ -1,5 +1,5 @@
 .
-.TH "ZSTD" "1" "2018-01-27" "zstd 1.3.4" "User Commands"
+.TH "ZSTD" "1" "October 2018" "zstd 1.3.7" "User Commands"
 .
 .SH "NAME"
 \fBzstd\fR \- zstd, zstdmt, unzstd, zstdcat \- Compress or decompress \.zst files
@@ -17,7 +17,7 @@
 \fBzstdcat\fR is equivalent to \fBzstd \-dcf\fR
 .
 .SH "DESCRIPTION"
-\fBzstd\fR is a fast lossless compression algorithm and data compression tool, with command line syntax similar to \fBgzip (1)\fR and \fBxz (1)\fR\. It is based on the \fBLZ77\fR family, with further FSE & huff0 entropy stages\. \fBzstd\fR offers highly configurable compression speed, with fast modes at > 200 MB/s per code, and strong modes nearing lzma compression ratios\. It also features a very fast decoder, with speeds > 500 MB/s per core\.
+\fBzstd\fR is a fast lossless compression algorithm and data compression tool, with command line syntax similar to \fBgzip (1)\fR and \fBxz (1)\fR\. It is based on the \fBLZ77\fR family, with further FSE & huff0 entropy stages\. \fBzstd\fR offers highly configurable compression speed, with fast modes at > 200 MB/s per core, and strong modes nearing lzma compression ratios\. It also features a very fast decoder, with speeds > 500 MB/s per core\.
 .
 .P
 \fBzstd\fR command line syntax is generally similar to gzip, but features the following differences :
@@ -100,6 +100,10 @@ Display information related to a zstd compressed file, such as size, ratio, and
 \fB#\fR compression level [1\-19] (default: 3)
 .
 .TP
+\fB\-\-fast[=#]\fR
+switch to ultra\-fast compression levels\. If \fB=#\fR is not present, it defaults to \fB1\fR\. The higher the value, the faster the compression speed, at the cost of some compression ratio\. This setting overwrites compression level if one was set previously\. Similarly, if a compression level is set after \fB\-\-fast\fR, it overrides it\.
+.
+.TP
 \fB\-\-ultra\fR
 unlocks high compression levels 20+ (maximum 22), using a lot more memory\. Note that decompression will also require more memory when using these levels\.
 .
@@ -112,14 +116,22 @@ Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \
 .
 .TP
 \fB\-T#\fR, \fB\-\-threads=#\fR
-Compress using \fB#\fR threads (default: 1)\. If \fB#\fR is 0, attempt to detect and use the number of physical CPU cores\. In all cases, the nb of threads is capped to ZSTDMT_NBTHREADS_MAX==256\. This modifier does nothing if \fBzstd\fR is compiled without multithread support\.
+Compress using \fB#\fR working threads (default: 1)\. If \fB#\fR is 0, attempt to detect and use the number of physical CPU cores\. In all cases, the nb of threads is capped to ZSTDMT_NBTHREADS_MAX==200\. This modifier does nothing if \fBzstd\fR is compiled without multithread support\.
+.
+.TP
+\fB\-\-single\-thread\fR
+Does not spawn a thread for compression, use a single thread for both I/O and compression\. In this mode, compression is serialized with I/O, which is slightly slower\. (This is different from \fB\-T1\fR, which spawns 1 compression thread in parallel of I/O)\. This mode is the only one available when multithread support is disabled\. Single\-thread mode features lower memory usage\. Final compressed result is slightly different from \fB\-T1\fR\.
+.
+.TP
+\fB\-\-adapt[=min=#,max=#]\fR
+\fBzstd\fR will dynamically adapt compression level to perceived I/O conditions\. Compression level adaptation can be observed live by using command \fB\-v\fR\. Adaptation can be constrained between supplied \fBmin\fR and \fBmax\fR levels\. The feature works when combined with multi\-threading and \fB\-\-long\fR mode\. It does not work with \fB\-\-single\-thread\fR\. It sets window size to 8 MB by default (can be changed manually, see \fBwlog\fR)\. Due to the chaotic nature of dynamic adaptation, compressed result is not reproducible\. \fInote\fR : at the time of this writing, \fB\-\-adapt\fR can remain stuck at low speed when combined with multiple worker threads (>=2)\.
 .
 .TP
 \fB\-D file\fR
 use \fBfile\fR as Dictionary to compress or decompress FILE(s)
 .
 .TP
-\fB\-\-nodictID\fR
+\fB\-\-no\-dictID\fR
 do not store dictionary ID within frame header (dictionary compression)\. The decoder will have to rely on implicit knowledge about which dictionary to use, it won\'t be able to check if it\'s correct\.
 .
 .TP
@@ -152,7 +164,7 @@ operate recursively on dictionaries
 .
 .TP
 \fB\-\-format=FORMAT\fR
-compress and decompress in other formats\. If compiled with support, zstd can compress to or decompress from other compression algorithm formats\. Possibly available options are \fBgzip\fR, \fBxz\fR, \fBlzma\fR, and \fBlz4\fR\.
+compress and decompress in other formats\. If compiled with support, zstd can compress to or decompress from other compression algorithm formats\. Possibly available options are \fBzstd\fR, \fBgzip\fR, \fBxz\fR, \fBlzma\fR, and \fBlz4\fR\. If no such format is provided, \fBzstd\fR is the default\.
 .
 .TP
 \fB\-h\fR/\fB\-H\fR, \fB\-\-help\fR
@@ -186,7 +198,7 @@ All arguments after \fB\-\-\fR are treated as files
 Use FILEs as training set to create a dictionary\. The training set should contain a lot of small files (> 100), and weight typically 100x the target dictionary size (for example, 10 MB for a 100 KB dictionary)\.
 .
 .IP
-Supports multithreading if \fBzstd\fR is compiled with threading support\. Additional parameters can be specified with \fB\-\-train\-cover\fR\. The legacy dictionary builder can be accessed with \fB\-\-train\-legacy\fR\. Equivalent to \fB\-\-train\-cover=d=8,steps=4\fR\.
+Supports multithreading if \fBzstd\fR is compiled with threading support\. Additional parameters can be specified with \fB\-\-train\-fastcover\fR\. The legacy dictionary builder can be accessed with \fB\-\-train\-legacy\fR\. The cover dictionary builder can be accessed with \fB\-\-train\-cover\fR\. Equivalent to \fB\-\-train\-fastcover=d=8,steps=4\fR\.
 .
 .TP
 \fB\-o file\fR
@@ -209,11 +221,11 @@ Split input files in blocks of size # (default: no split)
 A dictionary ID is a locally unique ID that a decoder can use to verify it is using the right dictionary\. By default, zstd will create a 4\-bytes random number ID\. It\'s possible to give a precise number instead\. Short numbers have an advantage : an ID < 256 will only need 1 byte in the compressed frame header, and an ID < 65536 will only need 2 bytes\. This compares favorably to 4 bytes default\. However, it\'s up to the dictionary manager to not assign twice the same ID to 2 different dictionaries\.
 .
 .TP
-\fB\-\-train\-cover[=k#,d=#,steps=#]\fR
-Select parameters for the default dictionary builder algorithm named cover\. If \fId\fR is not specified, then it tries \fId\fR = 6 and \fId\fR = 8\. If \fIk\fR is not specified, then it tries \fIsteps\fR values in the range [50, 2000]\. If \fIsteps\fR is not specified, then the default value of 40 is used\. Requires that \fId\fR <= \fIk\fR\.
+\fB\-\-train\-cover[=k#,d=#,steps=#,split=#]\fR
+Select parameters for the default dictionary builder algorithm named cover\. If \fId\fR is not specified, then it tries \fId\fR = 6 and \fId\fR = 8\. If \fIk\fR is not specified, then it tries \fIsteps\fR values in the range [50, 2000]\. If \fIsteps\fR is not specified, then the default value of 40 is used\. If \fIsplit\fR is not specified or split <= 0, then the default value of 100 is used\. Requires that \fId\fR <= \fIk\fR\.
 .
 .IP
-Selects segments of size \fIk\fR with highest score to put in the dictionary\. The score of a segment is computed by the sum of the frequencies of all the subsegments of size \fId\fR\. Generally \fId\fR should be in the range [6, 8], occasionally up to 16, but the algorithm will run faster with d <= \fI8\fR\. Good values for \fIk\fR vary widely based on the input data, but a safe range is [2 * \fId\fR, 2000]\. Supports multithreading if \fBzstd\fR is compiled with threading support\.
+Selects segments of size \fIk\fR with highest score to put in the dictionary\. The score of a segment is computed by the sum of the frequencies of all the subsegments of size \fId\fR\. Generally \fId\fR should be in the range [6, 8], occasionally up to 16, but the algorithm will run faster with d <= \fI8\fR\. Good values for \fIk\fR vary widely based on the input data, but a safe range is [2 * \fId\fR, 2000]\. If \fIsplit\fR is 100, all input samples are used for both training and testing to find optimal \fId\fR and \fIk\fR to build dictionary\. Supports multithreading if \fBzstd\fR is compiled with threading support\.
 .
 .IP
 Examples:
@@ -230,6 +242,25 @@ Examples:
 .IP
 \fBzstd \-\-train\-cover=k=50 FILEs\fR
 .
+.IP
+\fBzstd \-\-train\-cover=k=50,split=60 FILEs\fR
+.
+.TP
+\fB\-\-train\-fastcover[=k#,d=#,f=#,steps=#,split=#,accel=#]\fR
+Same as cover but with extra parameters \fIf\fR and \fIaccel\fR and different default value of split If \fIsplit\fR is not specified, then it tries \fIsplit\fR = 75\. If \fIf\fR is not specified, then it tries \fIf\fR = 20\. Requires that 0 < \fIf\fR < 32\. If \fIaccel\fR is not specified, then it tries \fIaccel\fR = 1\. Requires that 0 < \fIaccel\fR <= 10\. Requires that \fId\fR = 6 or \fId\fR = 8\.
+.
+.IP
+\fIf\fR is log of size of array that keeps track of frequency of subsegments of size \fId\fR\. The subsegment is hashed to an index in the range [0,2^\fIf\fR \- 1]\. It is possible that 2 different subsegments are hashed to the same index, and they are considered as the same subsegment when computing frequency\. Using a higher \fIf\fR reduces collision but takes longer\.
+.
+.IP
+Examples:
+.
+.IP
+\fBzstd \-\-train\-fastcover FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-fastcover=d=8,f=15,accel=2 FILEs\fR
+.
 .TP
 \fB\-\-train\-legacy[=selectivity=#]\fR
 Use legacy dictionary builder algorithm with the given dictionary \fIselectivity\fR (default: 9)\. The smaller the \fIselectivity\fR value, the denser the dictionary, improving its efficiency but reducing its possible maximum size\. \fB\-\-train\-legacy=s=#\fR is also accepted\.
@@ -335,13 +366,19 @@ The minimum \fIslen\fR is 3 and the maximum is 7\.
 .
 .TP
 \fBtargetLen\fR=\fItlen\fR, \fBtlen\fR=\fItlen\fR
-Specify the minimum match length that causes a match finder to stop searching for better matches\.
+The impact of this field vary depending on selected strategy\.
+.
+.IP
+For ZSTD_btopt and ZSTD_btultra, it specifies the minimum match length that causes match finder to stop searching for better matches\. A larger \fBtargetLen\fR usually improves compression ratio but decreases compression speed\.
+.
+.IP
+For ZSTD_fast, it triggers ultra\-fast mode when > 0\. The value represents the amount of data skipped between match sampling\. Impact is reversed : a larger \fBtargetLen\fR increases compression speed but decreases compression ratio\.
 .
 .IP
-A larger minimum match length usually improves compression ratio but decreases compression speed\. This option is only used with strategies ZSTD_btopt and ZSTD_btultra\.
+For all other strategies, this field has no impact\.
 .
 .IP
-The minimum \fItlen\fR is 4 and the maximum is 999\.
+The minimum \fItlen\fR is 0 and the maximum is 999\.
 .
 .TP
 \fBoverlapLog\fR=\fIovlog\fR, \fBovlog\fR=\fIovlog\fR
@@ -374,7 +411,7 @@ This option is ignored unless long distance matching is enabled\.
 Larger/very small values usually decrease compression ratio\.
 .
 .IP
-The minumum \fIldmslen\fR is 4 and the maximum is 4096 (default: 64)\.
+The minimum \fIldmslen\fR is 4 and the maximum is 4096 (default: 64)\.
 .
 .TP
 \fBldmBucketSizeLog\fR=\fIldmblog\fR, \fBldmblog\fR=\fIldmblog\fR
@@ -402,14 +439,14 @@ Larger values will improve compression speed\. Deviating far from the default va
 .IP
 The default value is \fBwlog \- ldmhlog\fR\.
 .
-.SS "\-B#:"
-Select the size of each compression job\. This parameter is available only when multi\-threading is enabled\. Default value is \fB4 * windowSize\fR, which means it varies depending on compression level\. \fB\-B#\fR makes it possible to select a custom value\. Note that job size must respect a minimum value which is enforced transparently\. This minimum is either 1 MB, or \fBoverlapSize\fR, whichever is largest\.
-.
 .SS "Example"
-The following parameters sets advanced compression options to those of predefined level 19 for files bigger than 256 KB:
+The following parameters sets advanced compression options to something similar to predefined level 19 for files bigger than 256 KB:
 .
 .P
-\fB\-\-zstd\fR=windowLog=23,chainLog=23,hashLog=22,searchLog=6,searchLength=3,targetLength=48,strategy=6
+\fB\-\-zstd\fR=wlog=23,clog=23,hlog=22,slog=6,slen=3,tlen=48,strat=6
+.
+.SS "\-B#:"
+Select the size of each compression job\. This parameter is available only when multi\-threading is enabled\. Default value is \fB4 * windowSize\fR, which means it varies depending on compression level\. \fB\-B#\fR makes it possible to select a custom value\. Note that job size must respect a minimum value which is enforced transparently\. This minimum is either 1 MB, or \fBoverlapSize\fR, whichever is largest\.
 .
 .SH "BUGS"
 Report bugs at: https://github\.com/facebook/zstd/issues