Messages in this thread Patch in this message | | | Date | Fri, 25 Mar 2022 18:53:54 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v7 11/13] perf tools: Improve IBS error handling |
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Em Fri, Mar 25, 2022 at 06:46:08PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Mar 22, 2022 at 03:15:15PM -0700, Stephane Eranian escreveu: > > From: Kim Phillips <kim.phillips@amd.com> > > > > improve the error message returned on failed perf_event_open() on AMD when > > using IBS. > > > > Output of executing 'perf record -e ibs_op// true' BEFORE this patch: > > > > The sys_perf_event_open() syscall returned with 22 (Invalid argument)for event (ibs_op//u). > > /bin/dmesg | grep -i perf may provide additional information. > > > > Output after: > > > > AMD IBS cannot exclude kernel events. Try running at a higher privilege level. > > So the error message don't match up the BEFORE part, that didn't have a > "u" at the end, and with this patch in:
I see, the patch description doesn't mention that the BEFORE command is run as a NON root user, when the 'u' suffix is auto-added by perf, I'm ammending the comment log message with this.
Now it reads:
---------------------------------------------------------------------- perf evsel: Improve AMD IBS (Instruction-Based Sampling) error handling messages
Improve the error message returned on failed perf_event_open() on AMD systems when using IBS (Instruction-Based Sampling).
Output of executing 'perf record -e ibs_op// true' as a non root user BEFORE this patch (perf will add the 'u' modifier at the end to exclude kernel/hypervisor sampling):
The sys_perf_event_open() syscall returned with 22 (Invalid argument)for event (ibs_op//u). /bin/dmesg | grep -i perf may provide additional information.
Output after:
AMD IBS can't exclude kernel events. Try running at a higher privilege level.
Output of executing 'sudo perf record -e ibs_op// true' BEFORE this patch:
Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (ibs_op//). /bin/dmesg | grep -i perf may provide additional information.
Output after:
Error: Invalid event (ibs_op//) in per-thread mode, enable system wide with '-a'.
Folowing the suggestion:
$ sudo perf record -a -e ibs_op// true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.664 MB perf.data (194 samples) ] $
Signed-off-by: Kim Phillips <kim.phillips@amd.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> ----------------------------------------------------------------------
This is all with:
[root@five ~]# uname -a Linux five 5.16.16-200.fc35.x86_64 #1 SMP PREEMPT Sat Mar 19 13:52:41 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
- Arnaldo > $ git log --oneline -1 > ca585f91ce13df4c (HEAD -> perf/core) perf evsel: Improve AMD IBS (Instruction-Based Sampling) error handling messages > # perf -v > perf version 5.17.gca585f91ce13 > # > > On a: > > # grep -m1 "model name" /proc/cpuinfo > model name : AMD Ryzen 9 5950X 16-Core Processor > # > > If I try: > > # perf record -e ibs_op//u true > Error: > Invalid event (ibs_op//u) in per-thread mode, enable system wide with '-a'. > # > > So now if I try: > > # perf record -a -e ibs_op//u true > Error: > AMD IBS can't exclude kernel events. Try running at a higher privilege level. > # > > So the problem is with the patch description, I'm fixing it. > > > Output of executing 'sudo perf record -e ibs_op// true' BEFORE this patch: > > > > Error: > > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (ibs_op//). > > /bin/dmesg | grep -i perf may provide additional information. > > > > Output after: > > > > Error: > > AMD IBS may only be available in system-wide/per-cpu mode. Try using -a, or -C and workload affinity > > But this one is never reached: > > [root@five ~]# perf record -e ibs_op// true > Error: > Invalid event (ibs_op//) in per-thread mode, enable system wide with '-a' > > > + if (!evsel->core.system_wide) > > + return scnprintf(msg, size, > > + "AMD IBS may only be available in system-wide/per-cpu mode. Try using -a, or -C and workload affinity"); > > > I'm applying this to make progress, the message now provides more clues. > > - Arnaldo > > > > Signed-off-by: Kim Phillips <kim.phillips@amd.com> > > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> > > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> > > Cc: Ian Rogers <irogers@google.com> > > Cc: Ingo Molnar <mingo@redhat.com> > > Cc: Jiri Olsa <jolsa@redhat.com> > > Cc: Joao Martins <joao.m.martins@oracle.com> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > Cc: Mark Rutland <mark.rutland@arm.com> > > Cc: Michael Petlan <mpetlan@redhat.com> > > Cc: Namhyung Kim <namhyung@kernel.org> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Robert Richter <robert.richter@amd.com> > > Cc: Stephane Eranian <eranian@google.com> > > --- > > tools/perf/util/evsel.c | 25 +++++++++++++++++++++++++ > > 1 file changed, 25 insertions(+) > > > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > > index 14b0e7ffa2c7..e8ff7a4bd490 100644 > > --- a/tools/perf/util/evsel.c > > +++ b/tools/perf/util/evsel.c > > @@ -2847,9 +2847,23 @@ static bool find_process(const char *name) > > return ret ? false : true; > > } > > > > +static bool is_amd(const char *arch, const char *cpuid) > > +{ > > + return arch && !strcmp("x86", arch) && cpuid && strstarts(cpuid, "AuthenticAMD"); > > +} > > + > > +static bool is_amd_ibs(struct evsel *evsel) > > +{ > > + return evsel->core.attr.precise_ip > > + || (evsel->pmu_name && !strncmp(evsel->pmu_name, "ibs", 3)); > > +} > > + > > int evsel__open_strerror(struct evsel *evsel, struct target *target, > > int err, char *msg, size_t size) > > { > > + struct perf_env *env = evsel__env(evsel); > > + const char *arch = perf_env__arch(env); > > + const char *cpuid = perf_env__cpuid(env); > > char sbuf[STRERR_BUFSIZE]; > > int printed = 0, enforced = 0; > > > > @@ -2949,6 +2963,17 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, > > return scnprintf(msg, size, > > "Invalid event (%s) in per-thread mode, enable system wide with '-a'.", > > evsel__name(evsel)); > > + if (is_amd(arch, cpuid)) { > > + if (is_amd_ibs(evsel)) { > > + if (evsel->core.attr.exclude_kernel) > > + return scnprintf(msg, size, > > + "AMD IBS can't exclude kernel events. Try running at a higher privilege level."); > > + if (!evsel->core.system_wide) > > + return scnprintf(msg, size, > > + "AMD IBS may only be available in system-wide/per-cpu mode. Try using -a, or -C and workload affinity"); > > + } > > + } > > + > > break; > > case ENODATA: > > return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. " > > -- > > 2.35.1.894.gb6a874cedc-goog > > -- > > - Arnaldo
--
- Arnaldo
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