diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | dbus/dbus-message.c | 89 |
2 files changed, 67 insertions, 27 deletions
@@ -1,5 +1,10 @@ 2004-11-26 Havoc Pennington <hp@redhat.com> + * dbus/dbus-message.c: reimplement message cache as an array which + makes the cache about twice as fast and saves maybe 1.5% overall + +2004-11-26 Havoc Pennington <hp@redhat.com> + * dbus/dbus-threads.c (init_global_locks): forgot to put the message cache lock here diff --git a/dbus/dbus-message.c b/dbus/dbus-message.c index cd8f1e3d..db9bc195 100644 --- a/dbus/dbus-message.c +++ b/dbus/dbus-message.c @@ -1393,16 +1393,27 @@ dbus_message_finalize (DBusMessage *message) * lock which could be a performance issue in certain cases. * * For the echo client/server the round trip time goes from around - * .000077 to .000070 with the message cache. The sysprof change is as - * follows (numbers are cumulative percentage): - * - * with cache: + * .000077 to .000069 with the message cache on my laptop. The sysprof + * change is as follows (numbers are cumulative percentage): + * + * with message cache implemented as array as it is now (0.000069 per): + * new_empty_header 1.46 + * mutex_lock 0.56 # i.e. _DBUS_LOCK(message_cache) + * mutex_unlock 0.25 + * self 0.41 + * unref 2.24 + * self 0.68 + * list_clear 0.43 + * mutex_lock 0.33 # i.e. _DBUS_LOCK(message_cache) + * mutex_unlock 0.25 + * + * with message cache implemented as list (0.000070 per roundtrip): * new_empty_header 2.72 * list_pop_first 1.88 * unref 3.3 * list_prepend 1.63 - * - * without cache: + * + * without cache (0.000077 per roundtrip): * new_empty_header 6.7 * string_init_preallocated 3.43 * dbus_malloc 2.43 @@ -1413,9 +1424,9 @@ dbus_message_finalize (DBusMessage *message) * dbus_free 1.63 * dbus_free 0.71 * - * The times for list operations with the cache seem to be from thread - * locks. So in a minute I'll try using an array instead of DBusList - * for the cache. + * If you implement the message_cache with a list, the primary reason + * it's slower is that you add another thread lock (on the DBusList + * mempool). */ /* Avoid caching huge messages */ @@ -1424,31 +1435,26 @@ dbus_message_finalize (DBusMessage *message) #define MAX_MESSAGE_CACHE_SIZE 5 _DBUS_DEFINE_GLOBAL_LOCK (message_cache); -static DBusList *message_cache = NULL; +static DBusMessage *message_cache[MAX_MESSAGE_CACHE_SIZE]; static int message_cache_count = 0; static dbus_bool_t message_cache_shutdown_registered = FALSE; static void dbus_message_cache_shutdown (void *data) { - DBusList *link; + int i; _DBUS_LOCK (message_cache); - - link = _dbus_list_get_first_link (&message_cache); - while (link != NULL) - { - DBusMessage *message = link->data; - DBusList *next = _dbus_list_get_next_link (&message_cache, link); - - dbus_message_finalize (message); - _dbus_list_free_link (link); + i = 0; + while (i < MAX_MESSAGE_CACHE_SIZE) + { + if (message_cache[i]) + dbus_message_finalize (message_cache[i]); - link = next; + ++i; } - message_cache = NULL; message_cache_count = 0; message_cache_shutdown_registered = FALSE; @@ -1466,6 +1472,7 @@ static DBusMessage* dbus_message_get_cached (void) { DBusMessage *message; + int i; message = NULL; @@ -1479,8 +1486,20 @@ dbus_message_get_cached (void) return NULL; } - message = _dbus_list_pop_first (&message_cache); - message_cache_count -= 1; + i = 0; + while (i < MAX_MESSAGE_CACHE_SIZE) + { + if (message_cache[i]) + { + message = message_cache[i]; + message_cache[i] = NULL; + message_cache_count -= 1; + break; + } + ++i; + } + _dbus_assert (i < MAX_MESSAGE_CACHE_SIZE); + _dbus_assert (message != NULL); _DBUS_UNLOCK (message_cache); @@ -1499,6 +1518,7 @@ static void dbus_message_cache_or_finalize (DBusMessage *message) { dbus_bool_t was_cached; + int i; _dbus_assert (message->refcount.value == 0); @@ -1517,9 +1537,18 @@ dbus_message_cache_or_finalize (DBusMessage *message) if (!message_cache_shutdown_registered) { + _dbus_assert (message_cache_count == 0); + if (!_dbus_register_shutdown_func (dbus_message_cache_shutdown, NULL)) goto out; + i = 0; + while (i < MAX_MESSAGE_CACHE_SIZE) + { + message_cache[i] = NULL; + ++i; + } + message_cache_shutdown_registered = TRUE; } @@ -1532,10 +1561,16 @@ dbus_message_cache_or_finalize (DBusMessage *message) if (message_cache_count > MAX_MESSAGE_CACHE_SIZE) goto out; - - if (!_dbus_list_prepend (&message_cache, message)) - goto out; + i = 0; + while (message_cache[i] != NULL) + { + ++i; + _dbus_assert (i < MAX_MESSAGE_CACHE_SIZE); + } + + _dbus_assert (message_cache[i] == NULL); + message_cache[i] = message; message_cache_count += 1; was_cached = TRUE; |