[tip:perf/urgent] perf tools: Disable parallelism for 'make clean'

[tip-bot for Rasmus Villemoes]

Commit-ID:  da15fc2fa9c07b23db8f5e479bd8a9f0d741ca07
Gitweb:     https://git.kernel.org/tip/da15fc2fa9c07b23db8f5e479bd8a9f0d741ca07
Author:     Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 5 Jul 2018 15:15:27 +0200
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 20 Aug 2018 08:54:58 -0300

perf tools: Disable parallelism for 'make clean'

The Yocto build system does a 'make clean' when rebuilding due to
changed dependencies, and that consistently fails for me (causing the
whole BSP build to fail) with errors such as

| find: '[...]/perf/1.0-r9/perf-1.0/plugin_mac80211.so': No such file or directory
| find: '[...]/perf/1.0-r9/perf-1.0/plugin_mac80211.so': No such file or directory
| find: find: '[...]/perf/1.0-r9/perf-1.0/libtraceevent.a''[...]/perf/1.0-r9/perf-1.0/libtraceevent.a': No such file or directory: No such file or directory
|
[...]
| find: cannot delete '/mnt/xfs/devel/pil/yocto/tmp-glibc/work/wandboard-oe-linux-gnueabi/perf/1.0-r9/perf-1.0/util/.pstack.o.cmd': No such file or directory

Apparently (despite the comment), 'make clean' ends up launching
multiple sub-makes that all want to remove the same things - perhaps
this only happens in combination with a O=... parameter. In any case, we
don't lose much by explicitly disabling the parallelism for the clean
target, and it makes automated builds much more reliable.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180705131527.19749-1-linux@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 225454416ed5..7902a5681fc8 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -84,10 +84,10 @@ endif # has_clean
 endif # MAKECMDGOALS
 
 #
-# The clean target is not really parallel, don't print the jobs info:
+# Explicitly disable parallelism for the clean target.
 #
 clean:
-	$(make)
+	$(make) -j1
 
 #
 # The build-test target is not really parallel, don't print the jobs info,