Threaded IO: make num of I/O threads configurable.

4 files changed, 10 insertions, 2 deletions

diff --git a/src/config.c b/src/config.c
index 1e0525594..c4a18f3bb 100644
--- a/src/config.c
+++ b/src/config.c
@@ -313,6 +313,11 @@ void loadServerConfigFromString(char *config) {
             if (server.dbnum < 1) {
                 err = "Invalid number of databases"; goto loaderr;
             }
+        } else if (!strcasecmp(argv[0],"io-threads") && argc == 2) {
+            server.io_threads_num = atoi(argv[1]);
+            if (server.io_threads_num < 1 || server.io_threads_num > 512) {
+                err = "Invalid number of I/O threads"; goto loaderr;
+            }
         } else if (!strcasecmp(argv[0],"include") && argc == 2) {
             loadServerConfig(argv[1],NULL);
         } else if (!strcasecmp(argv[0],"maxclients") && argc == 2) {
@@ -1426,6 +1431,7 @@ void configGetCommand(client *c) {
     config_get_numerical_field("cluster-announce-bus-port",server.cluster_announce_bus_port);
     config_get_numerical_field("tcp-backlog",server.tcp_backlog);
     config_get_numerical_field("databases",server.dbnum);
+    config_get_numerical_field("io-threads",server.io_threads_num);
     config_get_numerical_field("repl-ping-slave-period",server.repl_ping_slave_period);
     config_get_numerical_field("repl-ping-replica-period",server.repl_ping_slave_period);
     config_get_numerical_field("repl-timeout",server.repl_timeout);
@@ -2239,6 +2245,7 @@ int rewriteConfig(char *path) {
     rewriteConfigSaveOption(state);
     rewriteConfigUserOption(state);
     rewriteConfigNumericalOption(state,"databases",server.dbnum,CONFIG_DEFAULT_DBNUM);
+    rewriteConfigNumericalOption(state,"io-threads",server.dbnum,CONFIG_DEFAULT_IO_THREADS_NUM);
     rewriteConfigYesNoOption(state,"stop-writes-on-bgsave-error",server.stop_writes_on_bgsave_err,CONFIG_DEFAULT_STOP_WRITES_ON_BGSAVE_ERROR);
     rewriteConfigYesNoOption(state,"rdbcompression",server.rdb_compression,CONFIG_DEFAULT_RDB_COMPRESSION);
     rewriteConfigYesNoOption(state,"rdbchecksum",server.rdb_checksum,CONFIG_DEFAULT_RDB_CHECKSUM);
diff --git a/src/networking.c b/src/networking.c
index 916f29ebc..275338a6f 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -2525,7 +2525,6 @@ void *IOThreadMain(void *myid) {
 
 /* Initialize the data structures needed for threaded I/O. */
 void initThreadedIO(void) {
-    server.io_threads_num = 8;
     io_threads_active = 0; /* We start with threads not active. */
 
     /* Don't spawn any thread if the user selected a single thread:
@@ -2576,7 +2575,7 @@ int stopThreadedIOIfNeeded(void) {
     int pending = listLength(server.clients_pending_write);
 
     /* Return ASAP if IO threads are disabled (single threaded mode). */
-    if (server.io_threads_num == 1) return 0;
+    if (server.io_threads_num == 1) return 1;
 
     if (pending < (server.io_threads_num*2)) {
         if (io_threads_active) stopThreadedIO();
diff --git a/src/server.c b/src/server.c
index 325c9010c..f6d2b47f3 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2317,6 +2317,7 @@ void initServerConfig(void) {
     server.lazyfree_lazy_server_del = CONFIG_DEFAULT_LAZYFREE_LAZY_SERVER_DEL;
     server.always_show_logo = CONFIG_DEFAULT_ALWAYS_SHOW_LOGO;
     server.lua_time_limit = LUA_SCRIPT_TIME_LIMIT;
+    server.io_threads_num = CONFIG_DEFAULT_IO_THREADS_NUM;
 
     unsigned int lruclock = getLRUClock();
     atomicSet(server.lruclock,lruclock);
diff --git a/src/server.h b/src/server.h
index 96ee37887..2e4de2bb1 100644
--- a/src/server.h
+++ b/src/server.h
@@ -87,6 +87,7 @@ typedef long long mstime_t; /* millisecond time type. */
 #define CONFIG_DEFAULT_TCP_BACKLOG       511    /* TCP listen backlog. */
 #define CONFIG_DEFAULT_CLIENT_TIMEOUT       0   /* Default client timeout: infinite */
 #define CONFIG_DEFAULT_DBNUM     16
+#define CONFIG_DEFAULT_IO_THREADS_NUM 1         /* Single threaded by default */
 #define CONFIG_MAX_LINE    1024
 #define CRON_DBS_PER_CALL 16
 #define NET_MAX_WRITES_PER_EVENT (1024*64)