Re: [PATCH] perf/test: reduce run time of perf test Test java symbol

[Arnaldo Carvalho de Melo]

Em Tue, May 09, 2023 at 10:34:44AM -0700, Ian Rogers escreveu:
> On Tue, May 9, 2023 at 6:19 AM Thomas Richter <tmricht@xxxxxxxxxxxxx> wrote:
> >
> > Test case Test java symbol might run a long time. On Fedora 38 the
> > run time is very, very long:
> >
> >  Output before:
> >  # time ./perf test 108
> >  108: Test java symbol                  : Ok
> >  real   22m15.775s
> >  user   3m42.584s
> >  sys    4m30.685s
> >  #
> >
> > The reason is a lookup for the server for debug symbols as shown in
> >  # cat /etc/debuginfod/elfutils.urls
> >  https://debuginfod.fedoraproject.org/
> >  #
> > This lookup is done for every symbol/sample, so about 3500 lookups
> > will take place.
> > To omit this lookup, which is not needed, unset environment variable
> > DEBUGINFOD_URLS=''.
> >
> >  Output after:
> >  # time ./perf test 108
> >  108: Test java symbol                  : Ok
> >
> >  real   0m6.242s
> >  user   0m4.982s
> >  sys    0m3.243s
> >  #
> >
> > Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
> > Cc: leo.yan@xxxxxxxxxx
> > Cc: irogers@xxxxxxxxxx
> > ---
> >  tools/perf/tests/shell/test_java_symbol.sh | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/tests/shell/test_java_symbol.sh b/tools/perf/tests/shell/test_java_symbol.sh
> > index 90cea8811926..499539d1c479 100755
> > --- a/tools/perf/tests/shell/test_java_symbol.sh
> > +++ b/tools/perf/tests/shell/test_java_symbol.sh
> > @@ -56,7 +56,7 @@ if [ $? -ne 0 ]; then
> >         exit 1
> >  fi
> >
> > -if ! perf inject -i $PERF_DATA -o $PERF_INJ_DATA -j; then
> > +if ! DEBUGINFOD_URLS='' perf inject -i $PERF_DATA -o $PERF_INJ_DATA -j; then
> 
> Jiri, is this the best way to workaround a debuginfod slowness?

I noticed this delay, It is good that someone worked on rootcausing this
excessive delay, thanks Thomas.

I'll test it now.

- Arnaldo