INFO now contains the time (in usecs) needed to fork() in order to persist....

INFO now contains the time (in usecs) needed to fork() in order to persist. The info is available in the stats section of INFO.

src/aof.c

@@ -565,16 +565,18 @@ werr:
  */
 int rewriteAppendOnlyFileBackground(void) {
     pid_t childpid;
+    long long start;
 
     if (server.bgrewritechildpid != -1) return REDIS_ERR;
     if (server.ds_enabled != 0) {
         redisLog(REDIS_WARNING,"BGREWRITEAOF called with diskstore enabled: AOF is not supported when diskstore is enabled. Operation not performed.");
         return REDIS_ERR;
     }
+    start = ustime();
     if ((childpid = fork()) == 0) {
-        /* Child */
         char tmpfile[256];
 
+        /* Child */
         if (server.ipfd > 0) close(server.ipfd);
         if (server.sofd > 0) close(server.sofd);
         snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) getpid());
@@ -585,6 +587,7 @@ int rewriteAppendOnlyFileBackground(void) {
         }
     } else {
         /* Parent */
+        server.stat_fork_time = ustime()-start;
         if (childpid == -1) {
             redisLog(REDIS_WARNING,
                 "Can't rewrite append only file in background: fork: %s",

src/rdb.c

@@ -482,6 +482,7 @@ werr:
 
 int rdbSaveBackground(char *filename) {
     pid_t childpid;
+    long long start;
 
     if (server.bgsavechildpid != -1 ||
         server.bgsavethread != (pthread_t) -1) return REDIS_ERR;
@@ -493,6 +494,7 @@ int rdbSaveBackground(char *filename) {
         return dsRdbSaveBackground(filename);
     }
 
+    start = ustime();
     if ((childpid = fork()) == 0) {
         int retval;
 
@@ -503,6 +505,7 @@ int rdbSaveBackground(char *filename) {
         _exit((retval == REDIS_OK) ? 0 : 1);
     } else {
         /* Parent */
+        server.stat_fork_time = ustime()-start;
         if (childpid == -1) {
             redisLog(REDIS_WARNING,"Can't save in background: fork: %s",
                 strerror(errno));

src/redis.c

@@ -964,6 +964,7 @@ void initServer() {
     server.stat_keyspace_misses = 0;
     server.stat_keyspace_hits = 0;
     server.stat_peak_memory = 0;
+    server.stat_fork_time = 0;
     server.unixtime = time(NULL);
     aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL);
     if (server.ipfd > 0 && aeCreateFileEvent(server.el,server.ipfd,AE_READABLE,
@@ -1439,7 +1440,8 @@ sds genRedisInfoString(char *section) {
             "keyspace_hits:%lld\r\n"
             "keyspace_misses:%lld\r\n"
             "pubsub_channels:%ld\r\n"
-            "pubsub_patterns:%u\r\n",
+            "pubsub_patterns:%u\r\n"
+            "latest_fork_usec:%lld\r\n",
             server.stat_numconnections,
             server.stat_numcommands,
             server.stat_expiredkeys,
@@ -1447,7 +1449,8 @@ sds genRedisInfoString(char *section) {
             server.stat_keyspace_hits,
             server.stat_keyspace_misses,
             dictSize(server.pubsub_channels),
-            listLength(server.pubsub_patterns));
+            listLength(server.pubsub_patterns),
+            server.stat_fork_time);
     }
 
     /* Replication */

src/redis.h

@@ -547,6 +547,7 @@ struct redisServer {
     long long stat_keyspace_hits;   /* number of successful lookups of keys */
     long long stat_keyspace_misses; /* number of failed lookups of keys */
     size_t stat_peak_memory;        /* max used memory record */
+    long long stat_fork_time;       /* time needed to perform latets fork() */
     /* Configuration */
     int verbosity;
     int maxidletime;