xz.git - XZ Utils

Age	Commit message (Collapse)	Author	Files	Lines
2022-04-14	xz: Add a default soft memory usage limit for --threads=0.	Lasse Collin	1	-0/+27
	This is a soft limit in sense that it only affects the number of threads. It never makes xz fail and it never makes xz change settings that would affect the compressed output. The idea is to make -T0 have more reasonable behavior when the system has very many cores or when a memory-hungry compression options are used. This also helps with 32-bit xz, preventing it from running out of address space. The downside of this commit is that now the number of threads might become too low compared to what the user expected. I hope this to be an acceptable compromise as the old behavior has been a source of well-argued complaints for a long time.
2022-04-14	xz: Make -T0 use multithreaded mode on single-core systems.	Lasse Collin	1	-0/+4
	The main problem withi the old behavior is that the compressed output is different on single-core systems vs. multicore systems. This commit fixes it by making -T0 one thread in multithreaded mode on single-core systems. The downside of this is that it uses more memory. However, if --memlimit-compress is used, xz can (thanks to the previous commit) drop to the single-threaded mode still.
2022-04-12	xz: Add --memlimit-mt-decompress along with a default limit value.	Lasse Collin	1	-6/+11
	--memlimit-mt-decompress allows specifying the limit for multithreaded decompression. This matches memlimit_threading in liblzma. This limit can only affect the number of threads being used; it will never prevent xz from decompressing a file. The old --memlimit-decompress option is still used at the same time. If the value of --memlimit-decompress (the default value or one specified by the user) is less than the value of --memlimit-mt-decompress , then --memlimit-mt-decompress is reduced to match --memlimit-decompress. Man page wasn't updated yet.
2011-05-17	Add underscores to attributes (__attribute((__foo__))).	Lasse Collin	1	-1/+1

2011-04-09	xz: Minor internal changes to handling of --threads.	Lasse Collin	1	-5/+4
	Now it always defaults to one thread. Maybe this will change again if a threading method is added that doesn't affect memory usage.
2010-08-07	Disable the memory usage limiter by default.	Lasse Collin	1	-10/+13
	For several people, the limiter causes bigger problems that it solves, so it is better to have it disabled by default. Those who want to have a limiter by default need to enable it via the environment variable XZ_DEFAULTS. Support for environment variable XZ_DEFAULTS was added. It is parsed before XZ_OPT and technically identical with it. The intended uses differ quite a bit though; see the man page. The memory usage limit can now be set separately for compression and decompression using --memlimit-compress and --memlimit-decompress. To set both at once, -M or --memlimit can be used. --memory was retained as a legacy alias for --memlimit for backwards compatibility. The semantics of --info-memory were changed in backwards incompatible way. Compatibility wasn't meaningful due to changes in the memory usage limiter functionality. The memory usage limiter info is no longer shown at the bottom of xz --long -help. The memory usage limiter support for removed completely from xzdec. xz's man page was updated to match the above changes. Various unrelated fixes were also made to the man page.
2009-05-22	Make the default memory usage limit 40 % of RAM for both	Lasse Collin	1	-5/+5
	compressing and decompressing. This should be OK now that xz automatically scales down the compression settings if they would exceed the memory usage limit (earlier, the limit for compression was increased to 90 % because low limit broke scripts that used "xz -9" on systems with low RAM). Support spcifying the memory usage limit as a percentage of RAM (e.g. --memory=50%). Support --threads=0 to reset the thread limit to the default value (number of available CPU cores). Use UINT32_MAX instead of SIZE_MAX as the maximum in args.c. hardware.c was already expecting uint32_t value. Cleaned up the output of --help and --long-help.
2009-04-13	Put the interesting parts of XZ Utils into the public domain.	Lasse Collin	1	-10/+3
	Some minor documentation cleanups were made at the same time.
2009-02-14	Cleanups to the code that detects the amount of RAM and	Lasse Collin	1	-3/+8
	the number of CPU cores. Added support for using sysinfo() on Linux systems whose libc lacks appropriate sysconf() support (at least dietlibc). The Autoconf macros were split into separate files, and CPU core count detection was moved from hardware.c to cpucores.h. The core count isn't used for anything real for now, so a problematic part in process.c was commented out.
2009-02-05	Various code cleanups the the xz command line tool.	Lasse Collin	1	-9/+1
	It now builds with MinGW.
2008-11-19	Renamed lzma to xz and lzmadec to xzdec. We create symlinks	Lasse Collin	1	-0/+45
	lzma, unlzma, and lzcat in "make install" for backwards compatibility with LZMA Utils 4.32.x; I'm not sure if this should be the default though.