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authorLasse Collin <lasse.collin@tukaani.org>2024-02-13 11:38:10 +0200
committerLasse Collin <lasse.collin@tukaani.org>2024-02-14 18:31:16 +0200
commit0709c2b2d7c1d8f437b003f691880fd7810e5be5 (patch)
tree761b7261733169257a850f303e1ed0ada463ed19 /src
parentliblzma: Range decoder: Add x86-64 inline assembly. (diff)
downloadxz-0709c2b2d7c1d8f437b003f691880fd7810e5be5.tar.xz
xz: Fix outdated threading related info on the man page.
Diffstat (limited to 'src')
-rw-r--r--src/xz/xz.122
1 files changed, 14 insertions, 8 deletions
diff --git a/src/xz/xz.1 b/src/xz/xz.1
index f2c1ce35..6c8a52f5 100644
--- a/src/xz/xz.1
+++ b/src/xz/xz.1
@@ -4,7 +4,7 @@
.\" Authors: Lasse Collin
.\" Jia Tan
.\"
-.TH XZ 1 "2024-01-23" "Tukaani" "XZ Utils"
+.TH XZ 1 "2024-02-13" "Tukaani" "XZ Utils"
.
.SH NAME
xz, unxz, xzcat, lzma, unlzma, lzcat \- Compress or decompress .xz and .lzma files
@@ -799,8 +799,6 @@ in the single-threaded mode.
It may vary slightly between
.B xz
versions.
-Memory requirements of some of the future multithreaded modes may
-be dramatically higher than that of the single-threaded mode.
.IP \(bu 3
DecMem contains the decompressor memory requirements.
That is, the compression settings determine
@@ -809,6 +807,15 @@ The exact decompressor memory usage is slightly more than
the LZMA2 dictionary size, but the values in the table
have been rounded up to the next full MiB.
.RE
+.IP ""
+Memory requirements of the multi-threaded mode are
+significantly higher than that of the single-threaded mode.
+With the default value of
+.BR \-\-block\-size ,
+each thread needs 3*3*DictSize plus CompMem or DecMem.
+For example, four threads with preset
+.B \-6
+needs 660\(en670\ MiB of memory.
.TP
.BR \-e ", " \-\-extreme
Use a slower variant of the selected compression preset level
@@ -900,17 +907,16 @@ Using
.I size
less than the LZMA2 dictionary size is waste of RAM
because then the LZMA2 dictionary buffer will never get fully used.
-The sizes of the blocks are stored in the block headers,
-which a future version of
-.B xz
-will use for multi-threaded decompression.
+In multi-threaded mode,
+the sizes of the blocks are stored in the block headers.
+This size information is required for multi-threaded decompression.
.IP ""
In single-threaded mode no block splitting is done by default.
Setting this option doesn't affect memory usage.
No size information is stored in block headers,
thus files created in single-threaded mode
won't be identical to files created in multi-threaded mode.
-The lack of size information also means that a future version of
+The lack of size information also means that
.B xz
won't be able decompress the files in multi-threaded mode.
.TP