int j;
for (j = 0; j < server.dbnum; j++) {
+ /* Keys dictionary */
if (dictIsRehashing(server.db[j].dict)) {
dictRehashMilliseconds(server.db[j].dict,1);
break; /* already used our millisecond for this loop... */
}
+ /* Expires */
+ if (dictIsRehashing(server.db[j].expires)) {
+ dictRehashMilliseconds(server.db[j].expires,1);
+ break; /* already used our millisecond for this loop... */
+ }
}
}
* it will get more aggressive to avoid that too much memory is used by
* keys that can be removed from the keyspace. */
void activeExpireCycle(void) {
- int j;
+ int j, iteration = 0;
+ long long start = ustime(), timelimit;
+
+ /* We can use at max REDIS_EXPIRELOOKUPS_TIME_PERC percentage of CPU time
+ * per iteration. Since this function gets called with a frequency of
+ * REDIS_HZ times per second, the following is the max amount of
+ * microseconds we can spend in this function. */
+ timelimit = 1000000*REDIS_EXPIRELOOKUPS_TIME_PERC/REDIS_HZ/100;
+ if (timelimit <= 0) timelimit = 1;
for (j = 0; j < server.dbnum; j++) {
int expired;
/* Continue to expire if at the end of the cycle more than 25%
* of the keys were expired. */
do {
- long num = dictSize(db->expires);
+ unsigned long num = dictSize(db->expires);
+ unsigned long slots = dictSlots(db->expires);
long long now = mstime();
+ /* When there are less than 1% filled slots getting random
+ * keys is expensive, so stop here waiting for better times...
+ * The dictionary will be resized asap. */
+ if (num && slots > DICT_HT_INITIAL_SIZE &&
+ (num*100/slots < 1)) break;
+
+ /* The main collection cycle. Sample random keys among keys
+ * with an expire set, checking for expired ones. */
expired = 0;
if (num > REDIS_EXPIRELOOKUPS_PER_CRON)
num = REDIS_EXPIRELOOKUPS_PER_CRON;
server.stat_expiredkeys++;
}
}
+ /* We can't block forever here even if there are many keys to
+ * expire. So after a given amount of milliseconds return to the
+ * caller waiting for the other active expire cycle. */
+ iteration++;
+ if ((iteration & 0xf) == 0 && /* check once every 16 cycles. */
+ (ustime()-start) > timelimit) return;
} while (expired > REDIS_EXPIRELOOKUPS_PER_CRON/4);
}
}
}
void clientsCron(void) {
- /* Make sure to process at least 1/100 of clients per call.
- * Since this function is called 10 times per second we are sure that
+ /* Make sure to process at least 1/(REDIS_HZ*10) of clients per call.
+ * Since this function is called REDIS_HZ times per second we are sure that
* in the worst case we process all the clients in 10 seconds.
* In normal conditions (a reasonable number of clients) we process
* all the clients in a shorter time. */
int numclients = listLength(server.clients);
- int iterations = numclients/100;
+ int iterations = numclients/(REDIS_HZ*10);
if (iterations < 50)
iterations = (numclients < 50) ? numclients : 50;
}
}
+/* This is our timer interrupt, called REDIS_HZ times per second.
+ * Here is where we do a number of things that need to be done asynchronously.
+ * For instance:
+ *
+ * - Active expired keys collection (it is also performed in a lazy way on
+ * lookup).
+ * - Software watchdong.
+ * - Update some statistic.
+ * - Incremental rehashing of the DBs hash tables.
+ * - Triggering BGSAVE / AOF rewrite, and handling of terminated children.
+ * - Clients timeout of differnet kinds.
+ * - Replication reconnection.
+ * - Many more...
+ *
+ * Everything directly called here will be called REDIS_HZ times per second,
+ * so in order to throttle execution of things we want to do less frequently
+ * a macro is used: run_with_period(milliseconds) { .... }
+ */
+
+/* Using the following macro you can run code inside serverCron() with the
+ * specified period, specified in milliseconds.
+ * The actual resolution depends on REDIS_HZ. */
+#define run_with_period(_ms_) if (!(loops % ((_ms_)/(1000/REDIS_HZ))))
+
int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
int j, loops = server.cronloops;
REDIS_NOTUSED(eventLoop);
* To access a global var is faster than calling time(NULL) */
server.unixtime = time(NULL);
- trackOperationsPerSecond();
+ run_with_period(100) trackOperationsPerSecond();
/* We have just 22 bits per object for LRU information.
* So we use an (eventually wrapping) LRU clock with 10 seconds resolution.
}
/* Show some info about non-empty databases */
- for (j = 0; j < server.dbnum; j++) {
- long long size, used, vkeys;
-
- size = dictSlots(server.db[j].dict);
- used = dictSize(server.db[j].dict);
- vkeys = dictSize(server.db[j].expires);
- if (!(loops % 50) && (used || vkeys)) {
- redisLog(REDIS_VERBOSE,"DB %d: %lld keys (%lld volatile) in %lld slots HT.",j,used,vkeys,size);
- /* dictPrintStats(server.dict); */
+ run_with_period(5000) {
+ for (j = 0; j < server.dbnum; j++) {
+ long long size, used, vkeys;
+
+ size = dictSlots(server.db[j].dict);
+ used = dictSize(server.db[j].dict);
+ vkeys = dictSize(server.db[j].expires);
+ if (used || vkeys) {
+ redisLog(REDIS_VERBOSE,"DB %d: %lld keys (%lld volatile) in %lld slots HT.",j,used,vkeys,size);
+ /* dictPrintStats(server.dict); */
+ }
}
}
* a lot of memory movements in the parent will cause a lot of pages
* copied. */
if (server.rdb_child_pid == -1 && server.aof_child_pid == -1) {
- if (!(loops % 10)) tryResizeHashTables();
+ tryResizeHashTables();
if (server.activerehashing) incrementallyRehash();
}
/* Show information about connected clients */
- if (!(loops % 50)) {
+ run_with_period(5000) {
redisLog(REDIS_VERBOSE,"%d clients connected (%d slaves), %zu bytes in use",
listLength(server.clients)-listLength(server.slaves),
listLength(server.slaves),
/* Replication cron function -- used to reconnect to master and
* to detect transfer failures. */
- if (!(loops % 10)) replicationCron();
+ run_with_period(1000) replicationCron();
server.cronloops++;
- return 100;
+ return 1000/REDIS_HZ;
}
/* This function gets called every time Redis is entering the
projects / redis.git / blobdiff