Gentoo Development Guide

MULTIPROCESSING.ECLASS

Section: portage (5)
Updated: Feb 2018
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NAME

multiprocessing.eclass - multiprocessing helper functions  

DESCRIPTION

The multiprocessing eclass contains a suite of utility functions that could be helpful to controlling parallel multiple job execution. The most common use is processing MAKEOPTS in order to obtain job count.

 

EXAMPLE

src_compile() {
  # custom build system that does not support most of MAKEOPTS
  ./mybs -j$(makeopts_jobs)
}
 

FUNCTIONS

get_nproc [${fallback:-1}]
Attempt to figure out the number of processing units available. If the value can not be determined, prints the provided fallback instead. If no fallback is provided, defaults to 1.
makeopts_jobs [${MAKEOPTS}] [${inf:-999}]
Searches the arguments (defaults to ${MAKEOPTS}) and extracts the jobs number specified therein. Useful for running non-make tools in parallel too. i.e. if the user has MAKEOPTS=-j9, this will echo "9" -- we can't return the number as bash normalizes it to [0, 255]. If the flags haven't specified a -j flag, then "1" is shown as that is the default `make` uses. Since there's no way to represent infinity, we return ${inf} (defaults to 999) if the user has -j without a number.
makeopts_loadavg [${MAKEOPTS}] [${inf:-999}]
Searches the arguments (defaults to ${MAKEOPTS}) and extracts the value set for load-average. For make and ninja based builds this will mean new jobs are not only limited by the jobs-value, but also by the current load - which might get excessive due to I/O and not just due to CPU load. Be aware that the returned number might be a floating-point number. Test whether your software supports that. If no limit is specified or --load-average is used without a number, ${inf} (defaults to 999) is returned.
 

AUTHORS

Brian Harring <ferringb@gentoo.org>
Mike Frysinger <vapier@gentoo.org>
 

MAINTAINERS

base-system@gentoo.org
 

REPORTING BUGS

Please report bugs via https://bugs.gentoo.org/  

FILES

multiprocessing.eclass  

SEE ALSO

ebuild(5)
https://gitweb.gentoo.org/repo/gentoo.git/log/eclass/multiprocessing.eclass


 

Index

NAME
DESCRIPTION
EXAMPLE
FUNCTIONS
AUTHORS
MAINTAINERS
REPORTING BUGS
FILES
SEE ALSO

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Time: 03:25:04 GMT, February 25, 2018