Re: [PATCH v2] perf test record.sh: Raise limit of open file descriptors

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Tue, May 21, 2024 at 11:27:56AM +0200, Michael Petlan wrote:
> On Mon, 29 Apr 2024, vmolnaro@redhat.com wrote:
> > From: Veronika Molnarova <vmolnaro@redhat.com>
> > 
> > Subtest for system-wide record with '--threads=cpu' option fails due
> > to a limit of open file descriptors on systems with 128 or more CPUs
> > as the default limit is set to 1024.
> > 
> > The number of open file descriptors should be slightly above
> > nmb_events*nmb_cpus + nmb_cpus(for perf.data.n) + 4*nmb_cpus(for pipes),
> > which equals 8*nmb_cpus. Therefore, temporarily raise the limit to
> > 16*nmb_cpus for the test.
> > 
> > Signed-off-by: Veronika Molnarova <vmolnaro@redhat.com>
> 
> Acked-by: Michael Petlan <mpetlan@redhat.com>

b4 got confused, I'll pick the rigth version manually...

⬢[acme@toolbox perf-tools-next]$ b4 am -ctsl --cc-trailers 20240429085721.10122-1-vmolnaro@redhat.com
Grabbing thread from lore.kernel.org/all/20240429085721.10122-1-vmolnaro@redhat.com/t.mbox.gz
Checking for newer revisions
Grabbing search results from lore.kernel.org
Analyzing 7 messages in the thread
WARNING: duplicate messages found at index 1
   Subject 1: perf test record.sh: Raise limit of open file descriptors
   Subject 2: perf test record.sh: Raise limit of open file descriptors
  2 is not a reply... assume additional patch
Looking for additional code-review trailers on lore.kernel.org
Will use the latest revision: v2
You can pick other revisions using the -vN flag
Checking attestation on all messages, may take a moment...
---
  ✓ [PATCH v2] perf test record.sh: Raise limit of open file descriptors
    + Link: https://lore.kernel.org/r/20240311081127.7652-1-vmolnaro@redhat.com (✓ DKIM/kernel.org)
    + Acked-by: Michael Petlan <mpetlan@redhat.com> (✓ DKIM/redhat.com)
    + Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
  ✓ [PATCH v2] perf test record.sh: Raise limit of open file descriptors
    + Acked-by: Michael Petlan <mpetlan@redhat.com> (✓ DKIM/redhat.com)
    + Link: https://lore.kernel.org/r/20240429085721.10122-1-vmolnaro@redhat.com
    + Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
  ---
  ✓ Signed: DKIM/redhat.com
---
Total patches: 2
---
 Link: https://lore.kernel.org/r/20240311081127.7652-1-vmolnaro@redhat.com
 Base: not specified
       git am ./v2_20240311_vmolnaro_perf_test_record_sh_raise_limit_of_open_file_descriptors.mbx
⬢[acme@toolbox perf-tools-next]$

> > ---
> > Reworked the patch as the testfile has already changed since the patch
> > was sent causing the applying to fail, now applying upstream without
> > problems.
> >  tools/perf/tests/shell/record.sh | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> > index 3d1a7759a7b2..344c0e40ebe8 100755
> > --- a/tools/perf/tests/shell/record.sh
> > +++ b/tools/perf/tests/shell/record.sh
> > @@ -21,6 +21,15 @@ testprog="perf test -w thloop"
> >  cpu_pmu_dir="/sys/bus/event_source/devices/cpu*"
> >  br_cntr_file="/caps/branch_counter_nr"
> >  br_cntr_output="branch stack counters"
> > +default_fd_limit=$(ulimit -n)
> > +# With option --threads=cpu the number of open file descriptors should be
> > +# equal to sum of:    nmb_cpus * nmb_events (2+dummy),
> > +#                     nmb_threads for perf.data.n (equal to nmb_cpus) and
> > +#                     2*nmb_cpus of pipes = 4*nmb_cpus (each pipe has 2 ends)
> > +# All together it needs 8*nmb_cpus file descriptors plus some are also used
> > +# outside of testing, thus raising the limit to 16*nmb_cpus
> > +min_fd_limit=$(($(getconf _NPROCESSORS_ONLN) * 16))
> > +
> >  
> >  cleanup() {
> >    rm -rf "${perfdata}"
> > @@ -190,11 +199,19 @@ test_branch_counter() {
> >    echo "Basic branch counter test [Success]"
> >  }
> >  
> > +# raise the limit of file descriptors to minimum
> > +if [[ $default_fd_limit -lt $min_fd_limit ]]; then
> > +       ulimit -n $min_fd_limit
> > +fi
> > +
> >  test_per_thread
> >  test_register_capture
> >  test_system_wide
> >  test_workload
> >  test_branch_counter
> >  
> > +# restore the default value
> > +ulimit -n $default_fd_limit
> > +
> >  cleanup
> >  exit $err
> > -- 
> > 2.43.0
> > 
> > 
>