Re: [PATCH] perf: build reproducibility improvements

[Jiri Olsa <jolsa@redhat.com>]

On Mon, Mar 15, 2021 at 04:45:55PM +0000, Denys Zagorui -X (dzagorui - GLOBALLOGIC INC at Cisco) wrote:
> > Makefile.config:1026: No openjdk development package found, please install JDK package, e.g. openjdk-8-jdk, java-1.8.0-openjdk-devel
> > cp: '/home/jolsa/kernel/linux-perf/tools/perf/Documentation/tips.txt' and 'Documentation/tips.txt' are the same file
> >  BISON    util/parse-events-bison.c
> > bison: unrecognized option '--file-prefix-map=='
> 
> I thought that this flag was added in v3.6.3 because in git history next tag after corresponding bison patch was v3.6.3. But this is not true.
> 
> > hum, do we actualy want this? I think we want the exact path
> > we used for compilation, no? what's the benefit?
> ...
> > same here, we want to be sure to use the python path
> > from the exact build laction no?
> 
> This patch makes perf build more deterministic. This means that if we build perf on two different
> build machines from exactly the same sources we will have absolutely identical binaries. To achieve
> this absolute paths should not be stored in resulting binary. That is why i tried to determine those paths
> in runtime instead of storing them in binary compile time.
> There is ongoing project
> https://reproducible-builds.org/reports/2021-02/ project
> Kernel already achieved this
> https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html

ok, haven't heard about this

> 
> This patch doesn't make perf 100% reproducible. There is one more known issue with pmu event ordering
> https://bugzilla.opensuse.org/show_bug.cgi?id=1180882

nice, the reason of pmu events is in random fashion,
so the resulting binary differs.. perhaps we could
use scandir with sort instead

jirka