diff options
| -rw-r--r-- | src/xz/xz.1 | 34 |
1 files changed, 20 insertions, 14 deletions
diff --git a/src/xz/xz.1 b/src/xz/xz.1 index 8601aba5..ef89f406 100644 --- a/src/xz/xz.1 +++ b/src/xz/xz.1 @@ -5,7 +5,7 @@ .\" This file has been put into the public domain. .\" You can do whatever you want with this file. .\" -.TH XZ 1 "2011-04-11" "Tukaani" "XZ Utils" +.TH XZ 1 "2011-04-12" "Tukaani" "XZ Utils" . .SH NAME xz, unxz, xzcat, lzma, unlzma, lzcat \- Compress or decompress .xz and .lzma files @@ -907,24 +907,30 @@ Automatic adjusting is always disabled when creating raw streams .TP \fB\-T\fR \fIthreads\fR, \fB\-\-threads=\fIthreads Specify the number of worker threads to use. +Setting +.I threads +to a special value +.B 0 +makes +.B xz +use as many threads as there are CPU cores on the system. The actual number of threads can be less than .I threads +if the input file is not big enough +for threading with the given settings or if using more threads would exceed the memory usage limit. .IP "" -.B "Multithreaded compression and decompression are not" -.B "implemented yet, so this option has no effect for now." +Currently the only threading method is to split the input into +blocks and compress them independently from each other. +The default block size depends on the compression level and +can be overriden with the +.BI \-\-block\-size= size +option. .IP "" -.B "As of writing (2010-09-27), it hasn't been decided" -.B "if threads will be used by default on multicore systems" -.B "once support for threading has been implemented." -.B "Comments are welcome." -The complicating factor is that using many threads -will increase the memory usage dramatically. -Note that if multithreading will be the default, -it will probably be done so that single-threaded and -multithreaded modes produce the same output, -so compression ratio won't be significantly affected -if threading will be enabled by default. +.B "It is possible that the details of this option change before" +.B "the next stable XZ Utils release." +.B "This may include the meaning of the special value 0." +.\" FIXME . .SS "Custom compressor filter chains" A custom filter chain allows specifying |