From 9fbc61f832ebf432326a90e28184dade05ee34a8 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Thu, 19 Mar 2020 13:25:01 -0700 Subject: [PATCH] perf pmu: Add support for PMU capabilities The PMU capabilities information, which is located at /sys/bus/event_source/devices//caps, is required by perf tool. For example, the max LBR information is required to stitch LBR call stack. Add perf_pmu__caps_parse() to parse the PMU capabilities information. The information is stored in a list. The following patch will store the capabilities information in perf header. Committer notes: Here's an example of such directories and its files in an i5 7th gen machine: [root@seventh ~]# ls -lad /sys/bus/event_source/devices/*/caps drwxr-xr-x. 2 root root 0 Apr 14 13:33 /sys/bus/event_source/devices/cpu/caps drwxr-xr-x. 2 root root 0 Apr 14 13:33 /sys/bus/event_source/devices/intel_pt/caps [root@seventh ~]# ls -la /sys/bus/event_source/devices/intel_pt/caps total 0 drwxr-xr-x. 2 root root 0 Apr 14 13:33 . drwxr-xr-x. 5 root root 0 Apr 14 13:12 .. -r--r--r--. 1 root root 4096 Apr 16 13:10 cr3_filtering -r--r--r--. 1 root root 4096 Apr 16 11:42 cycle_thresholds -r--r--r--. 1 root root 4096 Apr 16 13:10 ip_filtering -r--r--r--. 1 root root 4096 Apr 16 13:10 max_subleaf -r--r--r--. 1 root root 4096 Apr 14 13:33 mtc -r--r--r--. 1 root root 4096 Apr 14 13:33 mtc_periods -r--r--r--. 1 root root 4096 Apr 16 13:10 num_address_ranges -r--r--r--. 1 root root 4096 Apr 16 13:10 output_subsys -r--r--r--. 1 root root 4096 Apr 16 13:10 payloads_lip -r--r--r--. 1 root root 4096 Apr 16 13:10 power_event_trace -r--r--r--. 1 root root 4096 Apr 14 13:33 psb_cyc -r--r--r--. 1 root root 4096 Apr 14 13:33 psb_periods -r--r--r--. 1 root root 4096 Apr 16 13:10 ptwrite -r--r--r--. 1 root root 4096 Apr 16 13:10 single_range_output -r--r--r--. 1 root root 4096 Apr 16 12:03 topa_multiple_entries -r--r--r--. 1 root root 4096 Apr 16 13:10 topa_output [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/topa_output 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/topa_multiple_entries 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/mtc 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/power_event_trace 0 [root@seventh ~]# [root@seventh ~]# ls -la /sys/bus/event_source/devices/cpu/caps/ total 0 drwxr-xr-x. 2 root root 0 Apr 14 13:33 . drwxr-xr-x. 6 root root 0 Apr 14 13:12 .. -r--r--r--. 1 root root 4096 Apr 16 13:10 branches -r--r--r--. 1 root root 4096 Apr 14 13:33 max_precise -r--r--r--. 1 root root 4096 Apr 16 13:10 pmu_name [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/max_precise 3 [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/branches 32 [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/pmu_name skylake [root@seventh ~]# Wow, first time I've heard about /sys/bus/event_source/devices/cpu/caps/max_precise, I think I'll use it! :-) Signed-off-by: Kan Liang Reviewed-by: Andi Kleen Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexey Budankov Cc: Mathieu Poirier Cc: Michael Ellerman Cc: Namhyung Kim Cc: Pavel Gerasimov Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Stephane Eranian Cc: Vitaly Slobodskoy Link: http://lore.kernel.org/lkml/20200319202517.23423-2-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/pmu.c | 82 +++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/pmu.h | 9 +++++ 2 files changed, 91 insertions(+) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index bc912a84b5e9..d9f89ed18dea 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -850,6 +850,7 @@ static struct perf_pmu *pmu_lookup(const char *name) INIT_LIST_HEAD(&pmu->format); INIT_LIST_HEAD(&pmu->aliases); + INIT_LIST_HEAD(&pmu->caps); list_splice(&format, &pmu->format); list_splice(&aliases, &pmu->aliases); list_add_tail(&pmu->list, &pmus); @@ -1594,3 +1595,84 @@ int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, va_end(args); return ret; } + +static int perf_pmu__new_caps(struct list_head *list, char *name, char *value) +{ + struct perf_pmu_caps *caps = zalloc(sizeof(*caps)); + + if (!caps) + return -ENOMEM; + + caps->name = strdup(name); + if (!caps->name) + goto free_caps; + caps->value = strndup(value, strlen(value) - 1); + if (!caps->value) + goto free_name; + list_add_tail(&caps->list, list); + return 0; + +free_name: + zfree(caps->name); +free_caps: + free(caps); + + return -ENOMEM; +} + +/* + * Reading/parsing the given pmu capabilities, which should be located at: + * /sys/bus/event_source/devices//caps as sysfs group attributes. + * Return the number of capabilities + */ +int perf_pmu__caps_parse(struct perf_pmu *pmu) +{ + struct stat st; + char caps_path[PATH_MAX]; + const char *sysfs = sysfs__mountpoint(); + DIR *caps_dir; + struct dirent *evt_ent; + int nr_caps = 0; + + if (!sysfs) + return -1; + + snprintf(caps_path, PATH_MAX, + "%s" EVENT_SOURCE_DEVICE_PATH "%s/caps", sysfs, pmu->name); + + if (stat(caps_path, &st) < 0) + return 0; /* no error if caps does not exist */ + + caps_dir = opendir(caps_path); + if (!caps_dir) + return -EINVAL; + + while ((evt_ent = readdir(caps_dir)) != NULL) { + char path[PATH_MAX + NAME_MAX + 1]; + char *name = evt_ent->d_name; + char value[128]; + FILE *file; + + if (!strcmp(name, ".") || !strcmp(name, "..")) + continue; + + snprintf(path, sizeof(path), "%s/%s", caps_path, name); + + file = fopen(path, "r"); + if (!file) + continue; + + if (!fgets(value, sizeof(value), file) || + (perf_pmu__new_caps(&pmu->caps, name, value) < 0)) { + fclose(file); + continue; + } + + nr_caps++; + fclose(file); + } + + closedir(caps_dir); + + return nr_caps; +} diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 5fb3f16828df..1edd214b75a5 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -22,6 +22,12 @@ enum { struct perf_event_attr; +struct perf_pmu_caps { + char *name; + char *value; + struct list_head list; +}; + struct perf_pmu { char *name; __u32 type; @@ -33,6 +39,7 @@ struct perf_pmu { struct perf_cpu_map *cpus; struct list_head format; /* HEAD struct perf_pmu_format -> list */ struct list_head aliases; /* HEAD struct perf_pmu_alias -> list */ + struct list_head caps; /* HEAD struct perf_pmu_caps -> list */ struct list_head list; /* ELEM */ }; @@ -107,4 +114,6 @@ bool pmu_uncore_alias_match(const char *pmu_name, const char *name); int perf_pmu__convert_scale(const char *scale, char **end, double *sval); +int perf_pmu__caps_parse(struct perf_pmu *pmu); + #endif /* __PMU_H */