If number of events found from probe-cache is not equal to number of
existing events(fetched from uprobe_events), and somehow we decides
to record only existing events, we warn user about the same. For ex,
$ sudo ./perf probe sdt_libpthread:mutex_release
Added new events:
sdt_libpthread:mutex_release (on %mutex_release in
/usr/lib64/libpthread-2.24.so)
sdt_libpthread:mutex_release_1 (on %mutex_release in
/usr/lib64/libpthread-2.24.so)
sdt_libpthread:mutex_release_2 (on %mutex_release in
/usr/lib64/libpthread-2.24.so)
sdt_libpthread:mutex_release_3 (on %mutex_release in
/usr/lib64/libpthread-2.24.so)
$ sudo ./perf record -a -e sdt_libpthread:*
Warning: Recording on 4 occurrences of sdt_libpthread:*
Warning: Found 35 events from probe-cache with name 'sdt_libpthread:*'.
Since 4 probe points already exists, recording only them.
Hint: Please use 'perf probe -d sdt_libpthread:*' to allow record on all
events.
$ sudo ./perf evlist
sdt_libpthread:mutex_release_3
sdt_libpthread:mutex_release_2
sdt_libpthread:mutex_release_1
sdt_libpthread:mutex_release
Signed-off-by: Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com>
---
tools/perf/util/probe-event.c | 53 ++++++++++++++++++++++++++++---------------
1 file changed, 35 insertions(+), 18 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 94b9105..7bf8783 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -3523,22 +3523,15 @@ void remove_sdt_event_list(struct list_head *sdt_events)
free_sdt_list(sdt_events);
}
-static int get_sdt_events_from_cache(struct perf_probe_event *pev)
+static void sdt_warn_abt_exist_events(struct perf_probe_event *pev, int ctr)
{
- int ret = 0;
-
- pev->ntevs = find_cached_events_all(pev, &pev->tevs);
-
- if (pev->ntevs < 0) {
- pr_err("Error: Cache lookup failed (code: %d)\n", pev->ntevs);
- ret = pev->ntevs;
- } else if (!pev->ntevs) {
- pr_err("Error: %s:%s not found in the cache\n",
- pev->group, pev->event);
- ret = -EINVAL;
- }
-
- return ret;
+ pr_warning("Warning: Found %d events from probe-cache with name
'%s:%s'.\n"
+ "\t Since %d probe point%c already exists, recording only %s.\n"
+ "Hint: Please use 'perf probe -d %s:%s' to allow record on all
events.\n\n",
+ pev->ntevs, pev->group, pev->event, ctr,
+ ctr > 1 ? 's' : '\0',
+ ctr > 1 ? "them" : "it",
+ pev->group, pev->event);
}
static int add_event_to_sdt_evlist(struct probe_trace_event *tev,
@@ -3727,6 +3720,15 @@ int add_sdt_event(char *event, struct list_head
*sdt_evlist)
probe_conf.max_probes = MAX_PROBES;
probe_conf.force_add = 1;
+ /*
+ * This call is intentionally placed before fetching events
+ * from uprobe_events file. If number of events found from probe-
+ * cache is not equal to number of existing events, and somehow
+ * we decides to record only existing events, we warn user about
+ * the same (sdt_warn_abt_exist_events()).
+ */
+ pev->ntevs = find_cached_events_all(pev, &pev->tevs);
+
/* Fetch all sdt events from uprobe_events */
exst_ntevs = probe_file__get_sdt_events(&exst_tevs);
if (exst_ntevs < 0) {
@@ -3738,14 +3740,29 @@ int add_sdt_event(char *event, struct list_head
*sdt_evlist)
ret = sdt_event_probepoint_exists(pev, exst_tevs,
exst_ntevs, sdt_evlist);
if (ret) {
+ if (ret > 0 && pev->ntevs > 0 && ret != pev->ntevs)
+ sdt_warn_abt_exist_events(pev, ret);
ret = ret > 0 ? 0 : ret;
goto free_pev;
}
- /* Fetch all matching events from cache. */
- ret = get_sdt_events_from_cache(pev);
- if (ret < 0)
+ /*
+ * Check if find_cached_events_all() failed.
+ * We deliberately check failure of this function after checking
+ * entries in uprobe_events. Because, even if this function fails,
+ * we may find matching entry from uprobe_events and in that case
+ * we should continue recording that event.
+ */
+ if (pev->ntevs < 0) {
+ pr_err("Error: Cache lookup failed (code: %d)\n", pev->ntevs);
+ ret = pev->ntevs;
goto free_pev;
+ } else if (!pev->ntevs) {
+ pr_err("Error: %s:%s not found in the cache\n",
+ pev->group, pev->event);
+ ret = -EINVAL;
+ goto free_pev;
+ }
/*
* Merge events found from uprobe_events with events found
--
2.9.3
