Speed up probe registration for large amount of events

[lttng-ust.git] / liblttng-ust / lttng-probes.c

diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c
index 9d7d83ceab716c62687bef3801ab0b59c6a56a0d..6b671da06c673ad0f6c59622062038439b46f138 100644 (file)
--- a/liblttng-ust/lttng-probes.c
+++ b/liblttng-ust/lttng-probes.c
@@ -58,19 +58,20 @@ const struct lttng_probe_desc *find_provider(const char *provider)
 }
 
 static
-const struct lttng_event_desc *find_event(const char *name)
+int check_event_provider(struct lttng_probe_desc *desc)
 {
-       struct lttng_probe_desc *probe_desc;
        int i;
+       size_t provider_name_len;
 
-       cds_list_for_each_entry(probe_desc, &probe_list, head) {
-               for (i = 0; i < probe_desc->nr_events; i++) {
-                       if (!strncmp(probe_desc->event_desc[i]->name, name,
-                                       LTTNG_UST_SYM_NAME_LEN - 1))
-                               return probe_desc->event_desc[i];
-               }
+       provider_name_len = strnlen(desc->provider,
+                               LTTNG_UST_SYM_NAME_LEN - 1);
+       for (i = 0; i < desc->nr_events; i++) {
+               if (strncmp(desc->event_desc[i]->name,
+                               desc->provider,
+                               provider_name_len))
+                       return 0;       /* provider mismatch */
        }
-       return NULL;
+       return 1;
 }
 
 int lttng_probe_register(struct lttng_probe_desc *desc)
@@ -80,20 +81,28 @@ int lttng_probe_register(struct lttng_probe_desc *desc)
        int i;
 
        ust_lock();
+
+       /*
+        * Check if the provider has already been registered.
+        */
        if (find_provider(desc->provider)) {
                ret = -EEXIST;
                goto end;
        }
+
        /*
-        * TODO: This is O(N^2). Turn into a hash table when probe registration
-        * overhead becomes an issue.
+        * Each provider enforce that every event name begins with the
+        * provider name. Check this in an assertion for extra
+        * carefulness. This ensures we cannot have duplicate event
+        * names across providers.
+        */
+       assert(check_event_provider(desc));
+
+       /*
+        * The provider ensures there are no duplicate event names.
+        * Duplicated TRACEPOINT_EVENT event names would generate a
+        * compile-time error due to duplicated symbol names.
         */
-       for (i = 0; i < desc->nr_events; i++) {
-               if (find_event(desc->event_desc[i]->name)) {
-                       ret = -EEXIST;
-                       goto end;
-               }
-       }
 
        /*
         * We sort the providers by struct lttng_probe_desc pointer
@@ -149,23 +158,6 @@ void ltt_probe_unregister(struct lttng_probe_desc *desc)
        lttng_probe_unregister(desc);
 }
 
-/*
- * called with UST lock held.
- */
-const struct lttng_event_desc *lttng_event_get(const char *name)
-{
-       const struct lttng_event_desc *event;
-
-       event = find_event(name);
-       if (!event)
-               return NULL;
-       return event;
-}
-
-void lttng_event_put(const struct lttng_event_desc *event)
-{
-}
-
 void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
 {
        struct tp_list_entry *list_entry, *tmp;