They were flushed once per application previously, causing workload with many applications to trigger too many flush on stop, which in turn caused buffer padding bloat.
* The pseudo-code for stop behavior on per-uid buffers was: flush session's buffers for each application: - stop tracing - wait quiescent - flush buffers - push metadata Now doing, for per-uid buffers: for each application: - stop tracing - wait quiescent - push metadata flush session's buffers * And for per-pid buffers: Previously: for each application: - stop tracing - wait quiescent - flush buffers - push metadata Now: for each application: - stop tracing - wait quiescent - push metadata for each application: - flush buffers Refs: #497 Signed-off-by: Mathieu Desnoyers <[email protected]> --- diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c index 9bd622d..9bd4e69 100644 --- a/src/bin/lttng-sessiond/ust-app.c +++ b/src/bin/lttng-sessiond/ust-app.c @@ -3550,6 +3550,7 @@ int ust_app_create_event_glb(struct ltt_ust_session *usess, /* * Start tracing for a specific UST session and app. */ +static int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app) { int ret = 0; @@ -3642,12 +3643,11 @@ error_unlock: /* * Stop tracing for a specific UST session and app. */ +static int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app) { int ret = 0; - struct lttng_ht_iter iter; struct ust_app_session *ua_sess; - struct ust_app_channel *ua_chan; struct ust_registry_session *registry; DBG("Stopping tracing for ust app pid %d", app->pid); @@ -3700,6 +3700,52 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app) health_code_update(); + registry = get_session_registry(ua_sess); + assert(registry); + /* Push metadata for application before freeing the application. */ + (void) push_metadata(registry, ua_sess->consumer); + + pthread_mutex_unlock(&ua_sess->lock); +end_no_session: + rcu_read_unlock(); + health_code_update(); + return 0; + +error_rcu_unlock: + pthread_mutex_unlock(&ua_sess->lock); + rcu_read_unlock(); + health_code_update(); + return -1; +} + +/* + * Flush buffers for a specific UST session and app. + */ +static +int ust_app_flush_trace(struct ltt_ust_session *usess, struct ust_app *app) +{ + int ret = 0; + struct lttng_ht_iter iter; + struct ust_app_session *ua_sess; + struct ust_app_channel *ua_chan; + + DBG("Flushing buffers for ust app pid %d", app->pid); + + rcu_read_lock(); + + if (!app->compatible) { + goto end_no_session; + } + + ua_sess = lookup_session_by_app(usess, app); + if (ua_sess == NULL) { + goto end_no_session; + } + + pthread_mutex_lock(&ua_sess->lock); + + health_code_update(); + /* Flushing buffers */ cds_lfht_for_each_entry(ua_sess->channels->ht, &iter.iter, ua_chan, node.node) { @@ -3723,22 +3769,11 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app) health_code_update(); - registry = get_session_registry(ua_sess); - assert(registry); - /* Push metadata for application before freeing the application. */ - (void) push_metadata(registry, ua_sess->consumer); - pthread_mutex_unlock(&ua_sess->lock); end_no_session: rcu_read_unlock(); health_code_update(); return 0; - -error_rcu_unlock: - pthread_mutex_unlock(&ua_sess->lock); - rcu_read_unlock(); - health_code_update(); - return -1; } /* @@ -3823,9 +3858,21 @@ int ust_app_stop_trace_all(struct ltt_ust_session *usess) rcu_read_lock(); - /* Flush all per UID buffers associated to that session. */ - if (usess->buffer_type == LTTNG_BUFFER_PER_UID) { + cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) { + ret = ust_app_stop_trace(usess, app); + if (ret < 0) { + /* Continue to next apps even on error */ + continue; + } + } + + /* Flush buffers */ + switch (usess->buffer_type) { + case LTTNG_BUFFER_PER_UID: + { struct buffer_reg_uid *reg; + + /* Flush all per UID buffers associated to that session. */ cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) { struct buffer_reg_channel *reg_chan; struct consumer_socket *socket; @@ -3848,14 +3895,20 @@ int ust_app_stop_trace_all(struct ltt_ust_session *usess) (void) consumer_flush_channel(socket, reg_chan->consumer_key); } } + break; } - - cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) { - ret = ust_app_stop_trace(usess, app); - if (ret < 0) { - /* Continue to next apps even on error */ - continue; + case LTTNG_BUFFER_PER_PID: + cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) { + ret = ust_app_flush_trace(usess, app); + if (ret < 0) { + /* Continue to next apps even on error */ + continue; + } } + break; + default: + assert(0); + break; } rcu_read_unlock(); diff --git a/src/bin/lttng-sessiond/ust-app.h b/src/bin/lttng-sessiond/ust-app.h index e0aa17a..255a75c 100644 --- a/src/bin/lttng-sessiond/ust-app.h +++ b/src/bin/lttng-sessiond/ust-app.h @@ -257,8 +257,6 @@ int ust_app_register_done(int sock) int ust_app_version(struct ust_app *app); void ust_app_unregister(int sock); unsigned long ust_app_list_count(void); -int ust_app_start_trace(struct ltt_ust_session *usess, struct ust_app *app); -int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app); int ust_app_start_trace_all(struct ltt_ust_session *usess); int ust_app_stop_trace_all(struct ltt_ust_session *usess); int ust_app_destroy_trace_all(struct ltt_ust_session *usess); -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
