perf evsel: Cache associated event_format

We already lookup the associated event_format when reading the perf.data
header, so that we can cache the tracepoint name in evsel->name, so do
it a little further and save the event_format itself, so that we can
avoid relookups in tools that need to access it.

Change the tools to take the most obvious advantage, when they were
using pevent_find_event directly. More work is needed for further
removing the need of a pointer to pevent, such as when asking for event
field values ("common_pid" and the other common fields and per
event_format fields).

This is something that was planned but only got actually done when
Andrey Wagin needed to do this lookup at perf_tool->sample() time, when
we don't have access to pevent (session->pevent) to use with
pevent_find_event().

Cc: Andrey Wagin <avagin@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-txkvew2ckko0b594ae8fbnyk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index ce4d1b0c3862..8006978d8398 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -27,6 +27,7 @@
 #include <errno.h>
 
 #include "../../perf.h"
+#include "../evsel.h"
 #include "../util.h"
 #include "../event.h"
 #include "../thread.h"
@@ -194,16 +195,21 @@ static void define_event_symbols(struct event_format *event,
                 define_event_symbols(event, ev_name, args->next);
 }
 
-static inline
-struct event_format *find_cache_event(struct pevent *pevent, int type)
+static inline struct event_format *find_cache_event(struct perf_evsel *evsel)
 {
         static char ev_name[256];
         struct event_format *event;
+        int type = evsel->attr.config;
 
+        /*
+         * XXX: Do we really need to cache this since now we have evsel->tp_format
+         * cached already? Need to re-read this "cache" routine that as well calls
+         * define_event_symbols() :-\
+         */
         if (events[type])
                 return events[type];
 
-        events[type] = event = pevent_find_event(pevent, type);
+        events[type] = event = evsel->tp_format;
         if (!event)
                 return NULL;
 
@@ -217,7 +223,7 @@ struct event_format *find_cache_event(struct pevent *pevent, int type)
 static void python_process_event(union perf_event *perf_event __unused,
                                  struct pevent *pevent,
                                  struct perf_sample *sample,
-                                 struct perf_evsel *evsel __unused,
+                                 struct perf_evsel *evsel,
                                  struct machine *machine __unused,
                                  struct thread *thread)
 {
@@ -228,7 +234,6 @@ static void python_process_event(union perf_event *perf_event __unused,
         unsigned long s, ns;
         struct event_format *event;
         unsigned n = 0;
-        int type;
         int pid;
         int cpu = sample->cpu;
         void *data = sample->raw_data;
@@ -239,11 +244,9 @@ static void python_process_event(union perf_event *perf_event __unused,
         if (!t)
                 Py_FatalError("couldn't create Python tuple");
 
-        type = trace_parse_common_type(pevent, data);
-
-        event = find_cache_event(pevent, type);
+        event = find_cache_event(evsel);
         if (!event)
-                die("ug! no event found for type %d", type);
+                die("ug! no event found for type %d", (int)evsel->attr.config);
 
         pid = trace_parse_common_pid(pevent, data);