On Tue, Nov 24, 2015 at 10:26:18AM +0100, Jiri Olsa wrote:
> On Tue, Nov 24, 2015 at 09:42:10AM +0100, Ingo Molnar wrote:
>
> SNIP
>
> > >
> > > >
> > > > Occasionally it also triggers a build failure:
> > > >
> > > > CC plugin_kvm.o
> > > > CC arch/common.o
> > > > CC util/db-export.o
> > > > LD plugin_kmem-in.o
> > > > fixdep: error opening depfile: ./.plugin_kmem.o.d: No such file or
> > > > directory
> > > > /home/mingo/tip/tools/build/Makefile.build:77: recipe for target
> > > > 'plugin_kmem.o'
> > > > failed
> > > > make[3]: *** [plugin_kmem.o] Error 2
> > > > Makefile:189: recipe for target 'plugin_kmem-in.o' failed
> > > > make[2]: *** [plugin_kmem-in.o] Error 2
> > > > Makefile.perf:424: recipe for target 'install-traceevent-plugins' failed
> > > > make[1]: *** [install-traceevent-plugins] Error 2
> > > > make[1]: *** Waiting for unfinished jobs....
> > > >
> > > > that too seems to be a result of unwanted, over-eager parallelism.
> > >
> > > hm, haven't seen that one for long time now ;-) will check
> >
> > So maybe that's a side effect, because I do:
> >
> > make clean install
> >
> > and maybe 'clean' happens in parallel with 'install'?
>
> the fixdep error indicates that it was invoked after building object
> plugin_kmem-in.o, but it could not find its dep file (.plugin_kmem-in.o.d)
> which is built within the object build.. so seems like race with clean
> or other build of the same object
>
> however ;-)
>
> The 'Makefile' processing itself isn't paralel and will exec
> clean and install targets serialized:
>
> ---
> [root@intel-wildcatpass-07 perf]# make clean install
> make -f Makefile.perf --no-print-directory -j88 O= clean
> CLEAN libtraceevent
> CLEAN libapi
> CLEAN libbpf
> CLEAN config
> CLEAN core-objs
> CLEAN core-progs
> CLEAN core-gen
> SUBDIR Documentation
> CLEAN Documentation
> CLEAN python
> BUILD: Doing 'make -j88' parallel build
> make -f Makefile.perf --no-print-directory -j88 O= install
>
> Auto-detecting system features:
> ... dwarf: [ on ]
> ... glibc: [ on ]
> ---
>
> I can't make that failure on 88 cpus server, I assume you can
> reproduce this fairly easily?
>
> Could you please share failing build output from:
> $ make V=1 clean install
>
> thanks,
> jirka
>
I think I found one race..
- having install-traceevent-plugins depend on $(LIBTRACEEVENT),
plugins will not be built as its prereq. and the target
install-traceevent-plugins itself will trigger plugins build
- but plugins build is also triggered by perf build itself
via libtraceevent_plugins target
so those 2 might race.. but as I said, I've never reproduced ;-)
Could you please give it a try?
thanks,
jirka
---
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 0d19d5447d6c..929a32ba15f5 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -420,7 +420,7 @@ $(LIBTRACEEVENT)-clean:
$(call QUIET_CLEAN, libtraceevent)
$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) O=$(OUTPUT) clean >/dev/null
-install-traceevent-plugins: $(LIBTRACEEVENT)
+install-traceevent-plugins: libtraceevent_plugins
$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT)
install_plugins
$(LIBAPI): fixdep FORCE
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