Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH 13/54] perf tools: Support perf event alias name | Date | Mon, 25 Jan 2016 09:56:00 +0000 |
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From: He Kuang <hekuang@huawei.com>
This patch is useful when trying to pass a perf event to BPF map. Before this patch we are unable to pass an event with config term to BPF maps. For example:
# perf record -a -e cycles/no-inherit,period=0x7fffffffffffffff/ \ -e './test_bpf_map_2.c/maps:pmu_map.event=cycles/no-inherit,period=0x7fffffffffffffff//' ls / event syntax error: '..ps:pmu_map.event=cycles/' \___ Event not found for map setting
Because those '/' and ',' embarrass parser.
This patch adds new bison rules for specifying an alias name to a perf event, which allows cmdline refer to previous defined perf event through its name. With this patch user can give alias name to a perf event using following cmdline. The above goal can be achieved using:
# perf record -a -e cyc=cycles/no-inherit,period=0x7fffffffffffffff/ \ -e './test_bpf_map_2.c/maps:pmu_map.event=cyc/' ls /
If alias is not provided (normal case):
# perf record -e cycles ...
It will be set to event's name automatically ('cycles' in the above example).
To allow parser refer to existing event selector, pass event list to 'struct parse_events_evlist'. perf_evlist__find_evsel_by_alias() is introduced to get evsel through its alias.
Test result: # cat ./test_bpf_map_2.c /************************ BEGIN **************************/ #include <uapi/linux/bpf.h> #define SEC(NAME) __attribute__((section(NAME), used)) struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; }; static int (*trace_printk)(const char *fmt, int fmt_size, ...) = (void *)BPF_FUNC_trace_printk; static int (*get_smp_processor_id)(void) = (void *)BPF_FUNC_get_smp_processor_id; static int (*perf_event_read)(struct bpf_map_def *, int) = (void *)BPF_FUNC_perf_event_read;
struct bpf_map_def SEC("maps") pmu_map = { .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, .key_size = sizeof(int), .value_size = sizeof(int), .max_entries = __NR_CPUS__, }; SEC("func_write=sys_write") int func_write(void *ctx) { unsigned long long val; char fmt[] = "sys_write: pmu=%llu\n"; val = perf_event_read(&pmu_map, get_smp_processor_id()); trace_printk(fmt, sizeof(fmt), val); return 0; }
SEC("func_write_return=sys_write%return") int func_write_return(void *ctx) { unsigned long long val = 0; char fmt[] = "sys_write_return: pmu=%llu\n"; val = perf_event_read(&pmu_map, get_smp_processor_id()); trace_printk(fmt, sizeof(fmt), val); return 0; } char _license[] SEC("license") = "GPL"; int _version SEC("version") = LINUX_VERSION_CODE; /************************* END ***************************/ # echo "" > /sys/kernel/debug/tracing/trace # ./perf record -a -e cyc=cycles/no-inherit,period=0x7fffffffffffffff/ \ -e './test_bpf_map_2.c/maps:pmu_map.event=cyc/' ls / [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.755 MB perf.data ] # cat /sys/kernel/debug/tracing/trace | grep ls ls-25328 [002] d... 940138.313178: : sys_write: pmu=4503165 ls-25328 [002] dN.. 940138.313207: : sys_write_return: pmu=4582975 ls-25328 [002] d... 940138.313211: : sys_write: pmu=4599840 ls-25328 [002] dN.. 940138.313220: : sys_write_return: pmu=4633352 # ./perf report --stdio Error: The perf.data file has no samples! ... (This is expected because we set period of cycles to a very large value to period of cycles event because we want to use this event as a counter only, don't need sampling)
# ./perf record -e cycles -e './test_bpf_map_2.c/maps:pmu_map.event=cycles/' ls / ERROR: Apply config to BPF failed: Doesn't support inherit event (Hint: use -i or use /no-inherit/ to turn off inherit)
Signed-off-by: He Kuang <hekuang@huawei.com> Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com --- tools/perf/util/bpf-loader.c | 2 +- tools/perf/util/evlist.c | 4 ++-- tools/perf/util/evsel.c | 1 + tools/perf/util/evsel.h | 1 + tools/perf/util/parse-events.c | 26 ++++++++++++++++++++++++++ tools/perf/util/parse-events.h | 4 ++++ tools/perf/util/parse-events.y | 15 ++++++++++++++- 7 files changed, 49 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 84b4581..2893b4e 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -1448,7 +1448,7 @@ int bpf__strerror_apply_obj_config(int err, char *buf, size_t size) bpf__strerror_entry(BPF_LOADER_ERRNO__OBJCONF_MAP_EVTDIM, "Cannot set event to BPF maps in multi-thread tracing"); bpf__strerror_entry(BPF_LOADER_ERRNO__OBJCONF_MAP_EVTINH, - "%s (Hint: use -i to turn off inherit)", emsg); + "%s (Hint: use -i or use /no-inherit/ to turn off inherit)", emsg); bpf__strerror_entry(BPF_LOADER_ERRNO__OBJCONF_MAP_EVTTYPE, "Can only put raw, hardware and BPF output event into a BPF map"); bpf__strerror_end(buf, size); diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 9b56390..890b08b 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1731,9 +1731,9 @@ perf_evlist__find_evsel_by_str(struct perf_evlist *evlist, struct perf_evsel *evsel; evlist__for_each(evlist, evsel) { - if (!evsel->name) + if (!evsel->alias) continue; - if (strcmp(str, evsel->name) == 0) + if (strcmp(str, evsel->alias) == 0) return evsel; } diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 4678086..7aebd5d 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1076,6 +1076,7 @@ void perf_evsel__exit(struct perf_evsel *evsel) thread_map__put(evsel->threads); zfree(&evsel->group_name); zfree(&evsel->name); + zfree(&evsel->alias); perf_evsel__object.fini(evsel); } diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 8e75434..19885fb 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -89,6 +89,7 @@ struct perf_evsel { int idx; u32 ids; char *name; + char *alias; double scale; const char *unit; struct event_format *tp_format; diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 6e2543c..1e0ac77 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1091,6 +1091,30 @@ int parse_events__modifier_group(struct list_head *list, return parse_events__modifier_event(list, event_mod, true); } +int parse_events__set_event_alias(struct parse_events_evlist *data, + struct list_head *list, + const char *str, + void *loc_alias_) +{ + struct perf_evsel *evsel; + YYLTYPE *loc_alias = loc_alias_; + + if (!str) + return 0; + + if (!list_is_singular(list)) { + struct parse_events_error *err = data->error; + + err->idx = loc_alias->first_column; + err->str = strdup("One alias can be applied to one event only"); + return -EINVAL; + } + + evsel = list_first_entry(list, struct perf_evsel, node); + evsel->alias = strdup(str); + return evsel->alias ? 0 : -ENOMEM; +} + void parse_events__set_leader(char *name, struct list_head *list) { struct perf_evsel *leader; @@ -1283,6 +1307,8 @@ int parse_events_name(struct list_head *list, char *name) __evlist__for_each(list, evsel) { if (!evsel->name) evsel->name = strdup(name); + if (!evsel->alias) + evsel->alias = strdup(name); } return 0; diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h index 2a2b172..20ad3c2 100644 --- a/tools/perf/util/parse-events.h +++ b/tools/perf/util/parse-events.h @@ -172,4 +172,8 @@ extern int is_valid_tracepoint(const char *event_string); int valid_event_mount(const char *eventfs); char *parse_events_formats_error_string(char *additional_terms); +int parse_events__set_event_alias(struct parse_events_evlist *data, + struct list_head *list, + const char *str, + void *loc_alias_); #endif /* __PERF_PARSE_EVENTS_H */ diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y index 8992d16..c3cbd7a 100644 --- a/tools/perf/util/parse-events.y +++ b/tools/perf/util/parse-events.y @@ -77,6 +77,7 @@ static inc_group_count(struct list_head *list, %type <head> event_bpf_file %type <head> event_def %type <head> event_mod +%type <head> event_alias %type <head> event_name %type <head> event %type <head> events @@ -193,13 +194,25 @@ event_name PE_MODIFIER_EVENT event_name event_name: -PE_EVENT_NAME event_def +PE_EVENT_NAME event_alias { ABORT_ON(parse_events_name($2, $1)); free($1); $$ = $2; } | +event_alias + +event_alias: +PE_NAME '=' event_def +{ + struct list_head *list = $3; + struct parse_events_evlist *data = _data; + + ABORT_ON(parse_events__set_event_alias(data, list, $1, &@1)); + $$ = list; +} +| event_def event_def: event_pmu | -- 1.8.3.4
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