[PATCH 2/4] coccicheck: enable paramap support

Luis R. Rodriguez
2016-06-10T20:42:25Z

Coccinelle has had paramap support since 1.0.2, this means
it supports --jobs, enabling built-in multithreaded functionality,
instead of needing one to script it out. Just look for --jobs
in the help output to determine if this is supported.

Also enable the load balancing to be dynamic, so that if a
thread finishes early we keep feeding it.

If --jobs is not supported we fallback to the old mechanism.

As a small example, prior to this change, on an 8-core system:

Before:

$ export COCCI=scripts/coccinelle/free/kfree.cocci
$ time make coccicheck MODE=report
...

real 29m14.912s
user 103m1.796s
sys 0m4.464s

After:

real 16m22.435s
user 128m30.060s
sys 0m2.712s

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
scripts/coccicheck | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/scripts/coccicheck b/scripts/coccicheck
index aa5e78fba270..eeb5fdc142ca 100755
--- a/scripts/coccicheck
+++ b/scripts/coccicheck
@@ -12,8 +12,8 @@ if [ ! -x "$SPATCH" ]; then
exit 1
fi

-trap kill_running SIGTERM SIGINT
-declare -a SPATCH_PID
+USE_JOBS="no"
+$SPATCH --help | grep "\-\-jobs" > /dev/null && USE_JOBS="yes"

# The verbosity may be set by the environmental parameter V=
# as for example with 'make V=1 coccicheck'
@@ -82,7 +82,21 @@ if [ "$ONLINE" = "0" ] ; then
echo ''
fi

-run_cmd() {
+if [ "$USE_JOBS" = "no" ]; then
+ trap kill_running SIGTERM SIGINT
+ declare -a SPATCH_PID
+else
+ OPTIONS="$OPTIONS --jobs $NPROC --chunksize 1"
+fi
+
+run_cmd_paramap() {
+ if [ $VERBOSE -ne 0 ] ; then
+ echo "Running ($NPROC in parallel): $@"
+ fi
+ $@
+}
+
+run_cmd_old() {
local i
if [ $VERBOSE -ne 0 ] ; then
echo "Running ($NPROC in parallel): $@"
@@ -97,6 +111,14 @@ run_cmd() {
wait
}

+run_cmd() {
+ if [ "$USE_JOBS" = "yes" ]; then
+ run_cmd_paramap $@
+ else
+ run_cmd_old $@
+ fi
+}
+
kill_running() {
for i in $(seq 0 $(( NPROC - 1 )) ); do
if [ $VERBOSE -eq 2 ] ; then
--
2.8.2