multiprocessing.eclass
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:-$(( $(get_nproc) + 1 ))}]
-
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. If the flags specify -j without a number, ${inf} is returned (defaults to nproc).
- makeopts_loadavg [${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.
Reporting Bugs
Please report bugs via https://bugs.gentoo.org/