perf probe: Simplify event naming

Simplify event naming as <symbol>_<seqnum>. Each event name is
globally unique (group name is not checked). So, if there is
schedule_0, next probe event on schedule() will be schedule_1.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091201002024.10235.2353.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 56 insertions, 14 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7f4f288c642e..e42f3acc9a7e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -403,6 +403,29 @@ void show_perf_probe_events(void)
         strlist__delete(rawlist);
 }
 
+/* Get current perf-probe event names */
+static struct strlist *get_perf_event_names(int fd)
+{
+        unsigned int i;
+        char *group, *event;
+        struct strlist *sl, *rawlist;
+        struct str_node *ent;
+
+        rawlist = get_trace_kprobe_event_rawlist(fd);
+
+        sl = strlist__new(false, NULL);
+        for (i = 0; i < strlist__nr_entries(rawlist); i++) {
+                ent = strlist__entry(rawlist, i);
+                parse_trace_kprobe_event(ent->s, &group, &event, NULL);
+                strlist__add(sl, event);
+                free(group);
+        }
+
+        strlist__delete(rawlist);
+
+        return sl;
+}
+
 static int write_trace_kprobe_event(int fd, const char *buf)
 {
         int ret;
@@ -416,30 +439,46 @@ static int write_trace_kprobe_event(int fd, const char *buf)
         return ret;
 }
 
+static void get_new_event_name(char *buf, size_t len, const char *base,
+                               struct strlist *namelist)
+{
+        int i, ret;
+        for (i = 0; i < MAX_EVENT_INDEX; i++) {
+                ret = e_snprintf(buf, len, "%s_%d", base, i);
+                if (ret < 0)
+                        die("snprintf() failed: %s", strerror(-ret));
+                if (!strlist__has_entry(namelist, buf))
+                        break;
+        }
+        if (i == MAX_EVENT_INDEX)
+                die("Too many events are on the same function.");
+}
+
 void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
 {
         int i, j, fd;
         struct probe_point *pp;
         char buf[MAX_CMDLEN];
+        char event[64];
+        struct strlist *namelist;
 
-        fd = open_kprobe_events(O_WRONLY, O_APPEND);
+        fd = open_kprobe_events(O_RDWR, O_APPEND);
+        /* Get current event names */
+        namelist = get_perf_event_names(fd);
 
         for (j = 0; j < nr_probes; j++) {
                 pp = probes + j;
-                if (pp->found == 1) {
-                        snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
-                                pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
-                                pp->function, pp->offset, pp->probes[0]);
+                for (i = 0; i < pp->found; i++) {
+                        /* Get an unused new event name */
+                        get_new_event_name(event, 64, pp->function, namelist);
+                        snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
+                                 pp->retprobe ? 'r' : 'p',
+                                 PERFPROBE_GROUP, event,
+                                 pp->probes[i]);
                         write_trace_kprobe_event(fd, buf);
-                } else
-                        for (i = 0; i < pp->found; i++) {
-                                snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
-                                        pp->retprobe ? 'r' : 'p',
-                                        PERFPROBE_GROUP,
-                                        pp->function, pp->offset, i,
-                                        pp->probes[i]);
-                                write_trace_kprobe_event(fd, buf);
-                        }
+                        /* Add added event name to namelist */
+                        strlist__add(namelist, event);
+                }
         }
         close(fd);
 }
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 88db7d1a9472..0c6fe56fe38a 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -12,4 +12,7 @@ extern int synthesize_trace_kprobe_event(struct probe_point *pp);
 extern void add_trace_kprobe_events(struct probe_point *probes, int nr_probes);
 extern void show_perf_probe_events(void);
 
+/* Maximum index number of event-name postfix */
+#define MAX_EVENT_INDEX 1024
+
 #endif /*_PROBE_EVENT_H */