[PATCH 5.16 119/121] perf parse: Fix event parser error for hybrid systems

Greg Kroah-Hartman
2022-03-14T12:33:35Z

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

commit 91c9923a473a694eb1c5c01ab778a77114969707 upstream.

This bug happened on hybrid systems when both cpu_core and cpu_atom
have the same event name such as "UOPS_RETIRED.MS" while their event
terms are different, then during perf stat, the event for cpu_atom
will parse fail and then no output for cpu_atom.

UOPS_RETIRED.MS -> cpu_core/period=0x1e8483,umask=0x4,event=0xc2,frontend=0x8/
UOPS_RETIRED.MS -> cpu_atom/period=0x1e8483,umask=0x1,event=0xc2/

It is because event terms in the "head" of parse_events_multi_pmu_add
will be changed to event terms for cpu_core after parsing UOPS_RETIRED.MS
for cpu_core, then when parsing the same event for cpu_atom, it still
uses the event terms for cpu_core, but event terms for cpu_atom are
different with cpu_core, the event parses for cpu_atom will fail. This
patch fixes it, the event terms should be parsed from the original
event.

This patch can work for the hybrid systems that have the same event
in more than 2 PMUs. It also can work in non-hybrid systems.

Before:

# perf stat -v -e UOPS_RETIRED.MS -a sleep 1

Using CPUID GenuineIntel-6-97-1
UOPS_RETIRED.MS -> cpu_core/period=0x1e8483,umask=0x4,event=0xc2,frontend=0x8/
Control descriptor is not initialized
UOPS_RETIRED.MS: 2737845 16068518485 16068518485

Performance counter stats for 'system wide':

2,737,845 cpu_core/UOPS_RETIRED.MS/

1.002553850 seconds time elapsed

After:

# perf stat -v -e UOPS_RETIRED.MS -a sleep 1

Using CPUID GenuineIntel-6-97-1
UOPS_RETIRED.MS -> cpu_core/period=0x1e8483,umask=0x4,event=0xc2,frontend=0x8/
UOPS_RETIRED.MS -> cpu_atom/period=0x1e8483,umask=0x1,event=0xc2/
Control descriptor is not initialized
UOPS_RETIRED.MS: 1977555 16076950711 16076950711
UOPS_RETIRED.MS: 568684 8038694234 8038694234

Performance counter stats for 'system wide':

1,977,555 cpu_core/UOPS_RETIRED.MS/
568,684 cpu_atom/UOPS_RETIRED.MS/

1.004758259 seconds time elapsed

Fixes: fb0811535e92c6c1 ("perf parse-events: Allow config on kernel PMU events")
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220307151627.30049-1-zhengjun.xing@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/parse-events.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1648,6 +1648,7 @@ int parse_events_multi_pmu_add(struct pa
{
struct parse_events_term *term;
struct list_head *list = NULL;
+ struct list_head *orig_head = NULL;
struct perf_pmu *pmu = NULL;
int ok = 0;
char *config;
@@ -1674,7 +1675,6 @@ int parse_events_multi_pmu_add(struct pa
}
list_add_tail(&term->list, head);

-
/* Add it for all PMUs that support the alias */
list = malloc(sizeof(struct list_head));
if (!list)
@@ -1687,13 +1687,15 @@ int parse_events_multi_pmu_add(struct pa

list_for_each_entry(alias, &pmu->aliases, list) {
if (!strcasecmp(alias->name, str)) {
+ parse_events_copy_term_list(head, &orig_head);
if (!parse_events_add_pmu(parse_state, list,
- pmu->name, head,
+ pmu->name, orig_head,
true, true)) {
pr_debug("%s -> %s/%s/\n", str,
pmu->name, alias->str);
ok++;
}
+ parse_events_terms__delete(orig_head);
}
}
}