linux-kernel - [PATCH 3/4] perf parse-events: Support different format of the topdown event name

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Date:   Fri, 13 May 2022 08:15:53 -0700
From:   kan.liang@...ux.intel.com
To:     acme@...nel.org, mingo@...hat.com, irogers@...gle.com,
        jolsa@...nel.org, namhyung@...nel.org,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Cc:     peterz@...radead.org, zhengjun.xing@...ux.intel.com,
        adrian.hunter@...el.com, ak@...ux.intel.com, eranian@...gle.com,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH 3/4] perf parse-events: Support different format of the topdown event name

From: Kan Liang <kan.liang@...ux.intel.com>

The evsel->name may have a different format for a topdown event, a pure
topdown name (e.g., topdown-fe-bound), or a PMU name + a topdown name
(e.g., cpu/topdown-fe-bound/). The cpu/topdown-fe-bound/ kind format
isn't supported by the arch_evlist__leader(). This format is a very
common format for a hybrid platform, which requires specifying the PMU
name for each event.

Without the patch,

$perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1

 Performance counter stats for 'system wide':

     <not counted>      instructions
     <not counted>      slots
   <not supported>      cpu/topdown-fe-bound/

       1.003482041 seconds time elapsed

Some events weren't counted. Try disabling the NMI watchdog:
        echo 0 > /proc/sys/kernel/nmi_watchdog
        perf stat ...
        echo 1 > /proc/sys/kernel/nmi_watchdog
The events in group usually have to be from the same PMU. Try reorganizing the group.


With the patch,

perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1

 Performance counter stats for 'system wide':

       157,383,996      slots
        25,011,711      instructions
        27,441,686      cpu/topdown-fe-bound/

       1.003530890 seconds time elapsed

Fixes: bc355822f0d9 ("perf parse-events: Move slots only with topdown")
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 tools/perf/arch/x86/util/evlist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
index cfc208d71f00..75564a7df15b 100644
--- a/tools/perf/arch/x86/util/evlist.c
+++ b/tools/perf/arch/x86/util/evlist.c
@@ -36,7 +36,7 @@ struct evsel *arch_evlist__leader(struct list_head *list)
 				if (slots == first)
 					return first;
 			}
-			if (!strncasecmp(evsel->name, "topdown", 7))
+			if (strcasestr(evsel->name, "topdown"))
 				has_topdown = true;
 			if (slots && has_topdown)
 				return slots;
-- 
2.35.1