-----Original Message-----
From: Mathieu Desnoyers [mailto:[email protected]]
Sent: January-16-13 10:15 AM
To: [email protected]
Subject: [lttng-dev] [RFC PATCH lttng-ust] Introduce hash table for
lttng_create_event_if_missing()
[...]
@@ -329,17 +331,19 @@ int lttng_event_create(const struct lttng_event_desc
*desc, {
[...]
- /*
- * This is O(n^2) (for each event, the loop is called at event
- * creation). Might require a hash if we have lots of events.
- */
- cds_list_for_each_entry(event, &chan->session->events_head, node) {
+ hash = jhash(event_name, name_len, 0);
+ head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE
- 1)];
+ cds_hlist_for_each_entry(event, node, head, hlist) {
[...]
>From other code:
#define LTTNG_UST_EVENT_HT_BITS 6
#define LTTNG_UST_EVENT_HT_SIZE (1U << LTTNG_UST_EVENT_HT_BITS)
The way I read this, if there's a substantial number of events, you're just
dividing the time required by a constant 64. The complexity remains the same.
Are you sure this is really a long term solution?
Anik
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