From 94dbfd6781a0e87b6faa6012810eb22e7d5b8a70 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Tue, 30 Nov 2021 09:49:45 -0800 Subject: [PATCH] perf parse-events: Architecture specific leader override Currently topdown events must appear after a slots event: $ perf stat -e '{slots,topdown-fe-bound}' /bin/true Performance counter stats for '/bin/true': 3,183,090 slots 986,133 topdown-fe-bound Reversing the events yields: $ perf stat -e '{topdown-fe-bound,slots}' /bin/true Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (topdown-fe-bound). For metrics the order of events is determined by iterating over a hashmap, and so slots isn't guaranteed to be first which can yield this error. Change the set_leader in parse-events, called when a group is closed, so that rather than always making the first event the leader, if the slots event exists then it is made the leader. It is then moved to the head of the evlist otherwise it won't be opened in the correct order. The result is: $ perf stat -e '{topdown-fe-bound,slots}' /bin/true Performance counter stats for '/bin/true': 3,274,795 slots 1,001,702 topdown-fe-bound A problem with this approach is the slots event is identified by name, names can be overwritten like 'cpu/slots,name=foo/' and this causes the leader change to fail. The change also modifies and fixes mixed groups like, with the change: $ perf stat -e '{instructions,slots,topdown-fe-bound}' -a -- sleep 2 Performance counter stats for 'system wide': 5574985410 slots 971981616 instructions 1348461887 topdown-fe-bound 2.001263120 seconds time elapsed Without the change: $ perf stat -e '{instructions,slots,topdown-fe-bound}' -a -- sleep 2 Performance counter stats for 'system wide': instructions slots topdown-fe-bound 2.006247990 seconds time elapsed Something that may be undesirable here is that the events are reordered in the output. Reviewed-by: Kajol Jain Signed-off-by: Ian Rogers Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Andi Kleen Cc: John Garry Cc: Kajol Jain Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Paul Clarke Cc: Peter Zijlstra Cc: Riccardo Mancini Cc: Stephane Eranian Cc: Vineet Singh Link: http://lore.kernel.org/lkml/20211130174945.247604-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/x86/util/evlist.c | 17 +++++++++++++++++ tools/perf/util/evlist.h | 1 + tools/perf/util/parse-events.c | 8 +++++++- 3 files changed, 25 insertions(+), 1 deletion(-) diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c index 0b0951030a2f..f924246eff78 100644 --- a/tools/perf/arch/x86/util/evlist.c +++ b/tools/perf/arch/x86/util/evlist.c @@ -17,3 +17,20 @@ int arch_evlist__add_default_attrs(struct evlist *evlist) else return parse_events(evlist, TOPDOWN_L1_EVENTS, NULL); } + +struct evsel *arch_evlist__leader(struct list_head *list) +{ + struct evsel *evsel, *first; + + first = list_first_entry(list, struct evsel, core.node); + + if (!pmu_have_event("cpu", "slots")) + return first; + + __evlist__for_each_entry(list, evsel) { + if (evsel->pmu_name && !strcmp(evsel->pmu_name, "cpu") && + evsel->name && strstr(evsel->name, "slots")) + return evsel; + } + return first; +} diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index 97bfb8d0be4f..993437ffe429 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -110,6 +110,7 @@ int __evlist__add_default_attrs(struct evlist *evlist, __evlist__add_default_attrs(evlist, array, ARRAY_SIZE(array)) int arch_evlist__add_default_attrs(struct evlist *evlist); +struct evsel *arch_evlist__leader(struct list_head *list); int evlist__add_dummy(struct evlist *evlist); diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 1d68167ab611..acf20ce98ce9 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1824,6 +1824,11 @@ out: return ret; } +__weak struct evsel *arch_evlist__leader(struct list_head *list) +{ + return list_first_entry(list, struct evsel, core.node); +} + void parse_events__set_leader(char *name, struct list_head *list, struct parse_events_state *parse_state) { @@ -1837,9 +1842,10 @@ void parse_events__set_leader(char *name, struct list_head *list, if (parse_events__set_leader_for_uncore_aliase(name, list, parse_state)) return; - leader = list_first_entry(list, struct evsel, core.node); + leader = arch_evlist__leader(list); __perf_evlist__set_leader(list, &leader->core); leader->group_name = name ? strdup(name) : NULL; + list_move(&leader->core.node, list); } /* list_event is assumed to point to malloc'ed memory */