perf probe: Simplify event naming
Masami Hiramatsu [Tue, 1 Dec 2009 00:20:25 +0000 (19:20 -0500)]
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>

tools/perf/util/probe-event.c
tools/perf/util/probe-event.h

index 7f4f288..e42f3ac 100644 (file)
@@ -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);
 }
index 88db7d1..0c6fe56 100644 (file)
@@ -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 */