From 6dde6429c5ff5b38d6d40a14a6ee105117e6364d Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Fri, 15 Jun 2018 12:11:05 +0200 Subject: [PATCH] perf stat: Remove duplicate event counting 'perf stat' shows a mismatch in perf stat regarding counter names on s390: Run command: [root@s35lp76 perf]# ./perf stat -e tx_nc_tend -v -- ~/mytesttx 1 >/tmp/111 tx_nc_tend: 1 573146 573146 tx_nc_tend: 1 573146 573146 Performance counter stats for '/root/mytesttx 1': 3 tx_nc_tend 0.001037252 seconds time elapsed [root@s35lp76 perf]# shows transaction counter tx_nc_tend with value 3 but it was triggered only once as seen by the output of mytesttx. When looking up the event name tx_nc_tend the following function sequence is called: parse_events_multi_pmu_add() +--> perf_pmu__scan() being called with NULL argument +--> pmu_read_sysfs() scans directory ../devices/ for all PMUs +--> perf_pmu__find() tries to find a PMU in the global pmu list. +--> pmu_lookup() called to read all file entries when not in global list. pmu_lookup() causes the issue. It calls +---> pmu_aliases() to read all the entries in the PMU directory. On s390 this is named /sys/devices/cpum_cf/events. +--> pmu_aliases_parse() reads all files and creates an alias for each file name. So we end up with first entry created by reading the sysfs file [root@s35lp76 perf]# cat /sys/devices/cpum_cf /events/TX_NC_TEND event=0x008d [root@s35lp76 perf]# Debug output shows this entry tx_nc_tend -> 'cpum_cf'/'event=0x008d '/ After all files in this directory have been read and aliases created this function is called: +--> pmu_add_cpu_aliases() This function looks up the CPU tables created by the json files. With json files for s390 now available all the aliases are added to the PMU alias list a second time. The second entry is added by reading the json file converted by jevent resulting in file pmu-events/pmu-events.c: { .name = "tx_nc_tend", .event = "event=0x8d", .desc = "Unit: cpum_cf Completed TEND \ instructions \ in non-constrained TX mode", .topic = "extended", .long_desc = "A TEND instruction has \ completed in a \ non-constrained \ transactional-execution mode", .pmu = "cpum_cf", }, Debug output shows this entry tx_nc_tend -> 'cpum_cf'/'event=0x8d'/ Function pmu_aliases_parse() and pmu_add_cpu_aliases() both use __perf_pmu__new_alias() to add an alias to the PMU alias list. There is no check if an alias already exist So we end up with 2 entries for tx_nc_tend in the PMU alias list. Having set up the PMU alias list for this PMU now parse_events_multi_add_pmu() reads the complete alias list and adds each alias with parse_events_add_pmu() to the global perfev_list. This causes the alias to be added multiple times to the event list. Fix this by making __perf_pmu__new_alias() to merge alias definitions if an alias is already on the alias list. Also print a debug message when the alias has mismatches in some fields. Output before: [root@s35lp76 perf]# ./perf stat -e tx_nc_tend -v \ -- ~/mytesttx 1 >/tmp/111 tx_nc_tend: 1 551446 551446 Performance counter stats for '/root/mytesttx 1': 3 tx_nc_tend 0.000961134 seconds time elapsed [root@s35lp76 perf]# Output after: [root@s35lp76 perf]# ./perf stat -e tx_nc_tend -v \ -- ~/mytesttx 1 >/tmp/111 tx_nc_tend: 1 551446 551446 Performance counter stats for '/root/mytesttx 1': 1 tx_nc_tend 0.000961134 seconds time elapsed [root@s35lp76 perf]# Signed-off-by: Thomas Richter Reviewed-by: Hendrik Brueckner Reviewed-by: Jiri Olsa Cc: Heiko Carstens Cc: Martin Schwidefsky Link: http://lkml.kernel.org/r/20180615101105.47047-3-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/pmu.c | 71 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 70 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index f321ce97d9ec..3ba6a1742f91 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -234,6 +234,74 @@ static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias, return 0; } +static void perf_pmu_assign_str(char *name, const char *field, char **old_str, + char **new_str) +{ + if (!*old_str) + goto set_new; + + if (*new_str) { /* Have new string, check with old */ + if (strcasecmp(*old_str, *new_str)) + pr_debug("alias %s differs in field '%s'\n", + name, field); + zfree(old_str); + } else /* Nothing new --> keep old string */ + return; +set_new: + *old_str = *new_str; + *new_str = NULL; +} + +static void perf_pmu_update_alias(struct perf_pmu_alias *old, + struct perf_pmu_alias *newalias) +{ + perf_pmu_assign_str(old->name, "desc", &old->desc, &newalias->desc); + perf_pmu_assign_str(old->name, "long_desc", &old->long_desc, + &newalias->long_desc); + perf_pmu_assign_str(old->name, "topic", &old->topic, &newalias->topic); + perf_pmu_assign_str(old->name, "metric_expr", &old->metric_expr, + &newalias->metric_expr); + perf_pmu_assign_str(old->name, "metric_name", &old->metric_name, + &newalias->metric_name); + perf_pmu_assign_str(old->name, "value", &old->str, &newalias->str); + old->scale = newalias->scale; + old->per_pkg = newalias->per_pkg; + old->snapshot = newalias->snapshot; + memcpy(old->unit, newalias->unit, sizeof(old->unit)); +} + +/* Delete an alias entry. */ +static void perf_pmu_free_alias(struct perf_pmu_alias *newalias) +{ + zfree(&newalias->name); + zfree(&newalias->desc); + zfree(&newalias->long_desc); + zfree(&newalias->topic); + zfree(&newalias->str); + zfree(&newalias->metric_expr); + zfree(&newalias->metric_name); + parse_events_terms__purge(&newalias->terms); + free(newalias); +} + +/* Merge an alias, search in alias list. If this name is already + * present merge both of them to combine all information. + */ +static bool perf_pmu_merge_alias(struct perf_pmu_alias *newalias, + struct list_head *alist) +{ + struct perf_pmu_alias *a; + + list_for_each_entry(a, alist, list) { + if (!strcasecmp(newalias->name, a->name)) { + perf_pmu_update_alias(a, newalias); + perf_pmu_free_alias(newalias); + return true; + } + } + return false; +} + static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name, char *desc, char *val, char *long_desc, char *topic, @@ -310,7 +378,8 @@ static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name, alias->per_pkg = perpkg && sscanf(perpkg, "%d", &num) == 1 && num == 1; alias->str = strdup(newval); - list_add_tail(&alias->list, list); + if (!perf_pmu_merge_alias(alias, list)) + list_add_tail(&alias->list, list); return 0; } -- 2.30.2