Re: [PATCH v3 11/13] perf tools: improve IBS error handling

Stephane Eranian
2021-12-01T20:42:30Z

Kim,

Could you send me the patch you want to integrate in the series. I
thought I had integrated the change in V3.

On Wed, Dec 1, 2021 at 7:30 AM Kim Phillips <kim.phillips@amd.com> wrote:
>
> Hi Stephane,
>
> This v3 looks like it's the same as in the v1 of the series,
> which got nacked by acme.
>
> Please use the newer patches provided. Instructions to do
> so haven't changed since then.
>
> Thanks,
>
> Kim
>
> On 11/30/21 7:02 PM, Stephane Eranian wrote:
> > From: Kim Phillips <kim.phillips@amd.com>
> >
> > This patch improves the error message returned on failed perf_event_open() on
> > AMD when using IBS.
> >
> > Signed-off-by: Kim Phillips <kim.phillips@amd.com>
> > ---
> > tools/perf/util/evsel.c | 42 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 42 insertions(+)
> >
> > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > index ac0127be0459..39e9063c0a80 100644
> > --- a/tools/perf/util/evsel.c
> > +++ b/tools/perf/util/evsel.c
> > @@ -2852,12 +2852,52 @@ static bool find_process(const char *name)
> > return ret ? false : true;
> > }
> >
> > +static bool is_amd;
> > +
> > +static char *fgrep(FILE *inf, const char *str)
> > +{
> > + char line[256];
> > + int slen = strlen(str);
> > +
> > + while (!feof(inf)) {
> > + if (!fgets(line, 256, inf))
> > + break;
> > + if (strncmp(line, str, slen))
> > + continue;
> > +
> > + return strdup(line);
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +static void detect_amd(void)
> > +{
> > + FILE *inf = fopen("/proc/cpuinfo", "r");
> > + char *res;
> > +
> > + if (!inf)
> > + return;
> > +
> > + res = fgrep(inf, "vendor_id");
> > +
> > + if (res) {
> > + char *s = strchr(res, ':');
> > +
> > + is_amd = s && !strcmp(s, ": AuthenticAMD\n");
> > + free(res);
> > + }
> > + fclose(inf);
> > +}
> > +
> > int evsel__open_strerror(struct evsel *evsel, struct target *target,
> > int err, char *msg, size_t size)
> > {
> > char sbuf[STRERR_BUFSIZE];
> > int printed = 0, enforced = 0;
> >
> > + detect_amd();
> > +
> > switch (err) {
> > case EPERM:
> > case EACCES:
> > @@ -2950,6 +2990,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
> > return scnprintf(msg, size, "wrong clockid (%d).", clockid);
> > if (perf_missing_features.aux_output)
> > return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
> > + if (is_amd && (evsel->core.attr.precise_ip || !strncmp(evsel->pmu_name, "ibs", 3)) && (evsel->core.attr.exclude_kernel))
> > + return scnprintf(msg, size, "AMD IBS can't exclude kernel events. Try running at a higher privilege level.");
> > break;
> > case ENODATA:
> > return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. "
> >