Dynamic HZ: separate hz from the configured hz.

This way we can remember what the user configured HZ is, but change the
actual HZ dynamically if needed in the dynamic HZ feature
implementation.

3 files changed, 15 insertions, 9 deletions

diff --git a/src/config.c b/src/config.c
index 54494c8e1..5acea06d5 100644
--- a/src/config.c
+++ b/src/config.c
@@ -441,9 +441,9 @@ void loadServerConfigFromString(char *config) {
                 err = "argument must be 'yes' or 'no'"; goto loaderr;
             }
         } else if (!strcasecmp(argv[0],"hz") && argc == 2) {
-            server.hz = atoi(argv[1]);
-            if (server.hz < CONFIG_MIN_HZ) server.hz = CONFIG_MIN_HZ;
-            if (server.hz > CONFIG_MAX_HZ) server.hz = CONFIG_MAX_HZ;
+            server.config_hz = atoi(argv[1]);
+            if (server.config_hz < CONFIG_MIN_HZ) server.config_hz = CONFIG_MIN_HZ;
+            if (server.config_hz > CONFIG_MAX_HZ) server.config_hz = CONFIG_MAX_HZ;
         } else if (!strcasecmp(argv[0],"appendonly") && argc == 2) {
             int yes;
 
@@ -1158,11 +1158,11 @@ void configSetCommand(client *c) {
     } config_set_numerical_field(
       "cluster-slave-validity-factor",server.cluster_slave_validity_factor,0,INT_MAX) {
     } config_set_numerical_field(
-      "hz",server.hz,0,INT_MAX) {
+      "hz",server.config_hz,0,INT_MAX) {
         /* Hz is more an hint from the user, so we accept values out of range
          * but cap them to reasonable values. */
-        if (server.hz < CONFIG_MIN_HZ) server.hz = CONFIG_MIN_HZ;
-        if (server.hz > CONFIG_MAX_HZ) server.hz = CONFIG_MAX_HZ;
+        if (server.config_hz < CONFIG_MIN_HZ) server.config_hz = CONFIG_MIN_HZ;
+        if (server.config_hz > CONFIG_MAX_HZ) server.config_hz = CONFIG_MAX_HZ;
     } config_set_numerical_field(
       "watchdog-period",ll,0,INT_MAX) {
         if (ll)
@@ -1329,7 +1329,7 @@ void configGetCommand(client *c) {
     config_get_numerical_field("slave-announce-port",server.slave_announce_port);
     config_get_numerical_field("min-slaves-to-write",server.repl_min_slaves_to_write);
     config_get_numerical_field("min-slaves-max-lag",server.repl_min_slaves_max_lag);
-    config_get_numerical_field("hz",server.hz);
+    config_get_numerical_field("hz",server.config_hz);
     config_get_numerical_field("cluster-node-timeout",server.cluster_node_timeout);
     config_get_numerical_field("cluster-migration-barrier",server.cluster_migration_barrier);
     config_get_numerical_field("cluster-slave-validity-factor",server.cluster_slave_validity_factor);
@@ -2098,7 +2098,7 @@ int rewriteConfig(char *path) {
     rewriteConfigYesNoOption(state,"activedefrag",server.active_defrag_enabled,CONFIG_DEFAULT_ACTIVE_DEFRAG);
     rewriteConfigYesNoOption(state,"protected-mode",server.protected_mode,CONFIG_DEFAULT_PROTECTED_MODE);
     rewriteConfigClientoutputbufferlimitOption(state);
-    rewriteConfigNumericalOption(state,"hz",server.hz,CONFIG_DEFAULT_HZ);
+    rewriteConfigNumericalOption(state,"hz",server.config_hz,CONFIG_DEFAULT_HZ);
     rewriteConfigYesNoOption(state,"aof-rewrite-incremental-fsync",server.aof_rewrite_incremental_fsync,CONFIG_DEFAULT_AOF_REWRITE_INCREMENTAL_FSYNC);
     rewriteConfigYesNoOption(state,"rdb-save-incremental-fsync",server.rdb_save_incremental_fsync,CONFIG_DEFAULT_RDB_SAVE_INCREMENTAL_FSYNC);
     rewriteConfigYesNoOption(state,"aof-load-truncated",server.aof_load_truncated,CONFIG_DEFAULT_AOF_LOAD_TRUNCATED);
diff --git a/src/server.c b/src/server.c
index 93c0a46fd..557af84d9 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1512,7 +1512,7 @@ void initServerConfig(void) {
     server.timezone = timezone; /* Initialized by tzset(). */
     server.configfile = NULL;
     server.executable = NULL;
-    server.hz = CONFIG_DEFAULT_HZ;
+    server.config_hz = CONFIG_DEFAULT_HZ;
     server.arch_bits = (sizeof(long) == 8) ? 64 : 32;
     server.port = CONFIG_DEFAULT_SERVER_PORT;
     server.tcp_backlog = CONFIG_DEFAULT_TCP_BACKLOG;
@@ -1991,6 +1991,7 @@ void initServer(void) {
             server.syslog_facility);
     }
 
+    server.hz = server.config_hz;
     server.pid = getpid();
     server.current_client = NULL;
     server.clients = listCreate();
@@ -3074,6 +3075,7 @@ sds genRedisInfoString(char *section) {
             "uptime_in_seconds:%jd\r\n"
             "uptime_in_days:%jd\r\n"
             "hz:%d\r\n"
+            "configured_hz:%d\r\n"
             "lru_clock:%ld\r\n"
             "executable:%s\r\n"
             "config_file:%s\r\n",
@@ -3097,6 +3099,7 @@ sds genRedisInfoString(char *section) {
             (intmax_t)uptime,
             (intmax_t)(uptime/(3600*24)),
             server.hz,
+            server.config_hz,
             (unsigned long) lruclock,
             server.executable ? server.executable : "",
             server.configfile ? server.configfile : "");
diff --git a/src/server.h b/src/server.h
index dae7561d8..4ac323da1 100644
--- a/src/server.h
+++ b/src/server.h
@@ -923,6 +923,9 @@ struct redisServer {
     char *configfile;           /* Absolute config file path, or NULL */
     char *executable;           /* Absolute executable file path. */
     char **exec_argv;           /* Executable argv vector (copy). */
+    int config_hz;              /* Configured HZ value. May be different than
+                                   the actual 'hz' field value if dynamic-hz
+                                   is enabled. */
     int hz;                     /* serverCron() calls frequency in hertz */
     redisDb *db;
     dict *commands;             /* Command table */