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authorArnaldo Carvalho de Melo <acme@redhat.com>2018-10-19 21:47:34 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-10-19 22:31:09 +0300
commit2fda5ada07f36f6cde39a52e7f05d86ea8ffdc33 (patch)
treed5692dada50340add7eb8a717a38a044b46c7b39 /tools/perf/util/parse-events.l
parent5067a8cdd4ce3588fca2e0ee554f0f081650de8f (diff)
downloadlinux-2fda5ada07f36f6cde39a52e7f05d86ea8ffdc33.tar.xz
perf evsel: Introduce per event max_events property
This simply adds the field to 'struct perf_evsel' and allows setting it via the event parser, to test it lets trace trace: First look at where in a function that receives an evsel we can put a probe to read how evsel->max_events was setup: # perf probe -x ~/bin/perf -L trace__event_handler <trace__event_handler@/home/acme/git/perf/tools/perf/builtin-trace.c:0> 0 static int trace__event_handler(struct trace *trace, struct perf_evsel *evsel, union perf_event *event __maybe_unused, struct perf_sample *sample) 3 { 4 struct thread *thread = machine__findnew_thread(trace->host, sample->pid, sample->tid); 5 int callchain_ret = 0; 7 if (sample->callchain) { 8 callchain_ret = trace__resolve_callchain(trace, evsel, sample, &callchain_cursor); 9 if (callchain_ret == 0) { 10 if (callchain_cursor.nr < trace->min_stack) 11 goto out; 12 callchain_ret = 1; } } See what variables we can probe at line 7: # perf probe -x ~/bin/perf -V trace__event_handler:7 Available variables at trace__event_handler:7 @<trace__event_handler+89> int callchain_ret struct perf_evsel* evsel struct perf_sample* sample struct thread* thread struct trace* trace union perf_event* event Add a probe at that line asking for evsel->max_events to be collected and named as "max_events": # perf probe -x ~/bin/perf trace__event_handler:7 'max_events=evsel->max_events' Added new event: probe_perf:trace__event_handler (on trace__event_handler:7 in /home/acme/bin/perf with max_events=evsel->max_events) You can now use it in all perf tools, such as: perf record -e probe_perf:trace__event_handler -aR sleep 1 Now use 'perf trace', here aliased to just 'trace' and trace trace, i.e. the first 'trace' is tracing just that 'probe_perf:trace__event_handler' event, while the traced trace is tracing all scheduler tracepoints, will stop at two events (--max-events 2) and will just set evsel->max_events for all the sched tracepoints to 9, we will see the output of both traces intermixed: # trace -e *perf:*event_handler trace --max-events 2 -e sched:*/nr=9/ 0.000 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=000 0.009 :0/0 sched:sched_wakeup:comm=rcu_sched pid=10 prio=120 target_cpu=000 0.000 trace/23949 probe_perf:trace__event_handler:(48c34a) max_events=0x9 0.046 trace/23949 probe_perf:trace__event_handler:(48c34a) max_events=0x9 # Now, if the traced trace sends its output to /dev/null, we'll see just what the first level trace outputs: that evsel->max_events is indeed being set to 9: # trace -e *perf:*event_handler trace -o /dev/null --max-events 2 -e sched:*/nr=9/ 0.000 trace/23961 probe_perf:trace__event_handler:(48c34a) max_events=0x9 0.030 trace/23961 probe_perf:trace__event_handler:(48c34a) max_events=0x9 # Now that we can set evsel->max_events, we can go to the next step, honour that per-event property in 'perf trace'. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-og00yasj276joem6e14l1eas@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/parse-events.l')
-rw-r--r--tools/perf/util/parse-events.l1
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 5f761f3ed0f3..7805c71aaae2 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -269,6 +269,7 @@ time { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_TIME); }
call-graph { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CALLGRAPH); }
stack-size { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_STACKSIZE); }
max-stack { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_MAX_STACK); }
+nr { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_MAX_EVENTS); }
inherit { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_INHERIT); }
no-inherit { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NOINHERIT); }
overwrite { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_OVERWRITE); }