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authorMichał Górny <mgorny@gentoo.org>2016-12-13 10:08:22 +0100
committerMichał Górny <mgorny@gentoo.org>2016-12-18 14:46:42 +0100
commitd9cde86b8e01a04b09c3cc7fb328d92428594828 (patch)
tree92ec1e06b3633a7f201e8262b143bd92b3291ef6 /eclass
parentmultiprocessing.eclass: Fix handling multiple short options (e.g. -kj) (diff)
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multiprocessing.eclass: Introduce get_nproc() to get no of CPUs
Introduce get_nproc(), a portable 'nproc' wrapper. It uses either 'nproc' or a fallback Python multiprocessing module call to attempt to determine the number of available processing units. This can be used e.g. to determine a safe number of jobs to run when MAKEOPTS specifies unlimited --jobs and the build system in question does not support --load-average.
Diffstat (limited to 'eclass')
-rw-r--r--eclass/multiprocessing.eclass32
1 files changed, 32 insertions, 0 deletions
diff --git a/eclass/multiprocessing.eclass b/eclass/multiprocessing.eclass
index 5a5fe9acb56..3c5dfff2d11 100644
--- a/eclass/multiprocessing.eclass
+++ b/eclass/multiprocessing.eclass
@@ -53,6 +53,38 @@ bashpid() {
sh -c 'echo ${PPID}'
}
+# @FUNCTION: get_nproc
+# @USAGE: [${fallback:-1}]
+# @DESCRIPTION:
+# 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.
+get_nproc() {
+ local nproc
+
+ # GNU
+ if type -P nproc &>/dev/null; then
+ nproc=$(nproc)
+ fi
+
+ # BSD
+ if [[ -z ${nproc} ]] && type -P sysctl &>/dev/null; then
+ nproc=$(sysctl -n hw.ncpu 2>/dev/null)
+ fi
+
+ # fallback to python2.6+
+ # note: this may fail (raise NotImplementedError)
+ if [[ -z ${nproc} ]] && type -P python &>/dev/null; then
+ nproc=$(python -c 'import multiprocessing; print(multiprocessing.cpu_count());' 2>/dev/null)
+ fi
+
+ if [[ -n ${nproc} ]]; then
+ echo "${nproc}"
+ else
+ echo "${1:-1}"
+ fi
+}
+
# @FUNCTION: makeopts_jobs
# @USAGE: [${MAKEOPTS}]
# @DESCRIPTION: