perf: Store trace event name/id pairs in perf.data

The trace event name<->id mapping is dynamic for each kernel
compile. In order for perf.data to be useable outside the actual
system, we thus need to store a table of this mapping for later
use.

This patch adds this table to perf.data, and provides helper
functions for lookup up fields from this table.

To avoid mistakes, lookup-from-table is kept completely seprate
from lookup-from-local-debugfs.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090912130405.6960d099@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 0 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a9bdcab8c070..89172fd0038b 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -6,6 +6,7 @@
 #include "exec_cmd.h"
 #include "string.h"
 #include "cache.h"
+#include "header.h"
 
 int                                     nr_counters;
 
@@ -687,11 +688,35 @@ modifier:
         return ret;
 }
 
+static void store_event_type(const char *orgname)
+{
+        char filename[PATH_MAX], *c;
+        FILE *file;
+        int id;
+
+        sprintf(filename, "/sys/kernel/debug/tracing/events/%s/id", orgname);
+        c = strchr(filename, ':');
+        if (c)
+                *c = '/';
+
+        file = fopen(filename, "r");
+        if (!file)
+                return;
+        if (fscanf(file, "%i", &id) < 1)
+                die("cannot store event ID");
+        fclose(file);
+        perf_header__push_event(id, orgname);
+}
+
+
 int parse_events(const struct option *opt __used, const char *str, int unset __used)
 {
         struct perf_counter_attr attr;
         enum event_result ret;
 
+        if (strchr(str, ':'))
+                store_event_type(str);
+
         for (;;) {
                 if (nr_counters == MAX_COUNTERS)
                         return -1;