From e2cb52612e348e4ec464a776ae3fb870a0c7f7d9 Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Thu, 21 Apr 2022 18:40:39 -0700 Subject: ref-manual: Add XZ_THREADS and XZ_MEMLIMIT XZ_THREADS and XZ_MEMLIMIT were introduced in dunfell. [RP improved an original patch from Paul] (From yocto-docs rev: 96defb66b775093b5270bd1ebad0461c2bba1e5b) Signed-off-by: Paul Eggleton Signed-off-by: Richard Purdie --- documentation/ref-manual/variables.rst | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst index 754e05c35a..34da5bd30c 100644 --- a/documentation/ref-manual/variables.rst +++ b/documentation/ref-manual/variables.rst @@ -8759,4 +8759,23 @@ system and gives an overview of their function and contents. The default value of :term:`XSERVER`, if not specified in the machine configuration, is "xserver-xorg xf86-video-fbdev xf86-input-evdev". - + + :term:`XZ_THREADS` + Specifies the number of parallel threads that should be used when + using xz compression. + + By default this scales with core count, but is never set less than 2 + to ensure that multi-threaded mode is always used so that the output + file contents are deterministic. Builds will work with a value of 1 + but the output will differ compared to the output from the compression + generated when more than one thread is used. + + On systems where many tasks run in parallel, setting a limit to this + can be helpful in controlling system resource usage. + + :term:`XZ_MEMLIMIT` + Specifies the maximum memory the xz compression should use as a percentage + of system memory. If unconstrained the xz compressor can use large amounts of + memory and become problematic with parallelism elsewhere in the build. + "50%" has been found to be a good value. + -- cgit v1.2.3-54-g00ecf