[PATCH] perf jevents: Fix event syntax error caused by ExtSel

[PATCH] perf jevents: Fix event syntax error caused by ExtSel

[zhengjun.xing]

From: Zhengjun Xing <zhengjun.xing@linux.intel.com>

In the origin code, when "ExtSel" is 1, the eventcode will change to
"eventcode |= 1 << 21”. For event “UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS",
its "ExtSel" is "1", its eventcode will change from 0x1E to 0x20001E,
but in fact the eventcode should <=0x1FF, so this will cause the parse
fail:

  # perf stat -e "UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS" -a sleep 0.1
event syntax error: '.._RxL_CREDITS_CONSUMED_VN0.DRS'
                                  \___ value too big for format, maximum is 511

On the perf kernel side, the kernel assumes the valid bits are continuous.
It will adjust the 0x100 (bit 8 for perf tool) to bit 21 in HW.

DEFINE_UNCORE_FORMAT_ATTR(event_ext, event, "config:0-7,21");

So the perf tool follows the kernel side and just set bit8 other than bit21.

Fixes: fedb2b518239 ("perf jevents: Add support for parsing uncore json files")
Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
---
 tools/perf/pmu-events/jevents.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
index cee61c4ed59e..e597e4bac90f 100644
--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -605,7 +605,7 @@ static int json_events(const char *fn,
 			} else if (json_streq(map, field, "ExtSel")) {
 				char *code = NULL;
 				addfield(map, &code, "", "", val);
-				eventcode |= strtoul(code, NULL, 0) << 21;
+				eventcode |= strtoul(code, NULL, 0) << 8;
 				free(code);
 			} else if (json_streq(map, field, "EventName")) {
 				addfield(map, &je.name, "", "", val);
-- 
2.25.1

Re: [PATCH] perf jevents: Fix event syntax error caused by ExtSel

[Ian Rogers]

On Wed, May 25, 2022 at 7:04 AM <zhengjun.xing@linux.intel.com> wrote:
>
> From: Zhengjun Xing <zhengjun.xing@linux.intel.com>
>
> In the origin code, when "ExtSel" is 1, the eventcode will change to
> "eventcode |= 1 << 21”. For event “UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS",
> its "ExtSel" is "1", its eventcode will change from 0x1E to 0x20001E,
> but in fact the eventcode should <=0x1FF, so this will cause the parse
> fail:
>
>   # perf stat -e "UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS" -a sleep 0.1
> event syntax error: '.._RxL_CREDITS_CONSUMED_VN0.DRS'
>                                   \___ value too big for format, maximum is 511
>
> On the perf kernel side, the kernel assumes the valid bits are continuous.
> It will adjust the 0x100 (bit 8 for perf tool) to bit 21 in HW.
>
> DEFINE_UNCORE_FORMAT_ATTR(event_ext, event, "config:0-7,21");
>
> So the perf tool follows the kernel side and just set bit8 other than bit21.
>
> Fixes: fedb2b518239 ("perf jevents: Add support for parsing uncore json files")
> Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
> Reviewed-by: Kan Liang <kan.liang@linux.intel.com>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/pmu-events/jevents.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
> index cee61c4ed59e..e597e4bac90f 100644
> --- a/tools/perf/pmu-events/jevents.c
> +++ b/tools/perf/pmu-events/jevents.c
> @@ -605,7 +605,7 @@ static int json_events(const char *fn,
>                         } else if (json_streq(map, field, "ExtSel")) {
>                                 char *code = NULL;
>                                 addfield(map, &code, "", "", val);
> -                               eventcode |= strtoul(code, NULL, 0) << 21;
> +                               eventcode |= strtoul(code, NULL, 0) << 8;
>                                 free(code);
>                         } else if (json_streq(map, field, "EventName")) {
>                                 addfield(map, &je.name, "", "", val);
> --
> 2.25.1
>

Re: [PATCH] perf jevents: Fix event syntax error caused by ExtSel

[Arnaldo Carvalho de Melo]

Em Wed, May 25, 2022 at 07:27:08AM -0700, Ian Rogers escreveu:
> On Wed, May 25, 2022 at 7:04 AM <zhengjun.xing@linux.intel.com> wrote:
> >
> > From: Zhengjun Xing <zhengjun.xing@linux.intel.com>
> >
> > In the origin code, when "ExtSel" is 1, the eventcode will change to
> > "eventcode |= 1 << 21”. For event “UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS",
> > its "ExtSel" is "1", its eventcode will change from 0x1E to 0x20001E,
> > but in fact the eventcode should <=0x1FF, so this will cause the parse
> > fail:
> >
> >   # perf stat -e "UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS" -a sleep 0.1
> > event syntax error: '.._RxL_CREDITS_CONSUMED_VN0.DRS'
> >                                   \___ value too big for format, maximum is 511
> >
> > On the perf kernel side, the kernel assumes the valid bits are continuous.
> > It will adjust the 0x100 (bit 8 for perf tool) to bit 21 in HW.
> >
> > DEFINE_UNCORE_FORMAT_ATTR(event_ext, event, "config:0-7,21");
> >
> > So the perf tool follows the kernel side and just set bit8 other than bit21.
> >
> > Fixes: fedb2b518239 ("perf jevents: Add support for parsing uncore json files")
> > Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
> > Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
> 
> Acked-by: Ian Rogers <irogers@google.com>

Thanks, applied.

- Arnaldo