+#define T_SEC_IN_USEC 1000000
+
+static int
+slap_timediff(struct timeval *tv_begin, struct timeval *tv_end)
+{
+ uint64_t t_begin, t_end, t_diff;
+
+ t_begin = T_SEC_IN_USEC * tv_begin->tv_sec + tv_begin->tv_usec;
+ t_end = T_SEC_IN_USEC * tv_end->tv_sec + tv_end->tv_usec;
+ t_diff = t_end - t_begin;
+
+ if ( t_diff < 0 )
+ t_diff = 0;
+
+ return (int)t_diff;
+}
+
+void
+slap_set_timing(struct timeval *tv_set)
+{
+ gettimeofday(tv_set, (struct timezone *)NULL);
+}
+
+int
+slap_measure_timing(struct timeval *tv_set, struct timeval *tv_measure)
+{
+ gettimeofday(tv_measure, (struct timezone *)NULL);
+ return(slap_timediff(tv_set, tv_measure));
+}
+
+#define EMA_WEIGHT 0.999000
+#define SLAP_ZN_LATENCY_HISTORY_QLEN 500
+int
+slap_zn_latency_history(void* ctx, int ea_latency)
+{
+/* TODO: monitor /proc/stat (swap) as well */
+ struct zone_heap* zh = ctx;
+ double t_diff = 0.0;
+
+ zh->zh_ema_latency = (double)ea_latency * (1.0 - EMA_WEIGHT)
+ + zh->zh_ema_latency * EMA_WEIGHT;
+ if (!zh->zh_swapping && zh->zh_ema_samples++ % 100 == 99) {
+ struct zone_latency_history *zlh_entry;
+ zlh_entry = ch_calloc(1, sizeof(struct zone_latency_history));
+ zlh_entry->zlh_latency = zh->zh_ema_latency;
+ LDAP_STAILQ_INSERT_TAIL(
+ &zh->zh_latency_history_queue, zlh_entry, zlh_next);
+ zh->zh_latency_history_qlen++;
+ while (zh->zh_latency_history_qlen > SLAP_ZN_LATENCY_HISTORY_QLEN) {
+ struct zone_latency_history *zlh;
+ zlh = LDAP_STAILQ_FIRST(&zh->zh_latency_history_queue);
+ LDAP_STAILQ_REMOVE_HEAD(
+ &zh->zh_latency_history_queue, zlh_next);
+ zh->zh_latency_history_qlen--;
+ ch_free(zlh);
+ }
+ if (zh->zh_latency_history_qlen == SLAP_ZN_LATENCY_HISTORY_QLEN) {
+ struct zone_latency_history *zlh_first, *zlh_last;
+ zlh_first = LDAP_STAILQ_FIRST(&zh->zh_latency_history_queue);
+ zlh_last = LDAP_STAILQ_LAST(&zh->zh_latency_history_queue,
+ zone_latency_history, zlh_next);
+ t_diff = zlh_last->zlh_latency - zlh_first->zlh_latency;
+ }
+ if (t_diff >= 2000) {
+ zh->zh_latency_jump++;
+ } else {
+ zh->zh_latency_jump = 0;
+ }
+ if (zh->zh_latency_jump > 3) {
+ zh->zh_latency_jump = 0;
+ zh->zh_swapping = 1;
+ }
+ }
+ return zh->zh_swapping;
+}