From e173f7a0e318156efbaefa4e27b02b1da008a337 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Wed, 2 Jul 2014 12:27:24 +0200
Subject: Latency monitor trheshold value is now configurable.

This commit adds both support for redis.conf and CONFIG SET/GET.
---
 redis.conf   | 21 +++++++++++++++++++++
 src/config.c | 14 ++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/redis.conf b/redis.conf
index 1103d6152..bd0a09f02 100644
--- a/redis.conf
+++ b/redis.conf
@@ -654,6 +654,27 @@ slowlog-log-slower-than 10000
 # You can reclaim memory used by the slow log with SLOWLOG RESET.
 slowlog-max-len 128
 
+################################ LATENCY MONITOR ##############################
+
+# The Redis latency monitoring subsystem samples different operations
+# at runtime in order to collect data related to possible sources of
+# latency of a Redis instance.
+#
+# Via the LATENCY command this information is available to the user that can
+# print graphs and obtain reports.
+#
+# The system only logs operations that were performed in a time equal or
+# greater than the amount of milliseconds specified via the
+# latency-monitor-threshold configuration directive. When its value is set
+# to zero, the latency monitor is turned off.
+#
+# By default latency monitoring is disabled since it is mostly not needed
+# if you don't have latency issues, and collecting data has a performance
+# impact, that while very small, can be measured under big load. Latency
+# monitoring can easily be enalbed at runtime using the command
+# "CONFIG SET latency-monitor-threshold <milliseconds>" if needed.
+latency-monitor-threshold 0
+
 ############################# Event notification ##############################
 
 # Redis can notify Pub/Sub clients about events happening in the key space.
diff --git a/src/config.c b/src/config.c
index a06b54580..b0fc50b9d 100644
--- a/src/config.c
+++ b/src/config.c
@@ -451,6 +451,14 @@ void loadServerConfigFromString(char *config) {
                    argc == 2)
         {
             server.slowlog_log_slower_than = strtoll(argv[1],NULL,10);
+        } else if (!strcasecmp(argv[0],"latency-monitor-threshold") &&
+                   argc == 2)
+        {
+            server.latency_monitor_threshold = strtoll(argv[1],NULL,10);
+            if (server.latency_monitor_threshold < 0) {
+                err = "The latency threshold can't be negative";
+                goto loaderr;
+            }
         } else if (!strcasecmp(argv[0],"slowlog-max-len") && argc == 2) {
             server.slowlog_max_len = strtoll(argv[1],NULL,10);
         } else if (!strcasecmp(argv[0],"client-output-buffer-limit") &&
@@ -787,6 +795,9 @@ void configSetCommand(redisClient *c) {
     } else if (!strcasecmp(c->argv[2]->ptr,"slowlog-max-len")) {
         if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
         server.slowlog_max_len = (unsigned)ll;
+    } else if (!strcasecmp(c->argv[2]->ptr,"latency-monitor-threshold")) {
+        if (getLongLongFromObject(o,&ll) == REDIS_ERR || ll < 0) goto badfmt;
+        server.latency_monitor_threshold = ll;
     } else if (!strcasecmp(c->argv[2]->ptr,"loglevel")) {
         if (!strcasecmp(o->ptr,"warning")) {
             server.verbosity = REDIS_WARNING;
@@ -996,6 +1007,8 @@ void configGetCommand(redisClient *c) {
     config_get_numerical_field("lua-time-limit",server.lua_time_limit);
     config_get_numerical_field("slowlog-log-slower-than",
             server.slowlog_log_slower_than);
+    config_get_numerical_field("latency-monitor-threshold",
+            server.latency_monitor_threshold);
     config_get_numerical_field("slowlog-max-len",
             server.slowlog_max_len);
     config_get_numerical_field("port",server.port);
@@ -1785,6 +1798,7 @@ int rewriteConfig(char *path) {
     rewriteConfigNumericalOption(state,"cluster-migration-barrier",server.cluster_migration_barrier,REDIS_CLUSTER_DEFAULT_MIGRATION_BARRIER);
     rewriteConfigNumericalOption(state,"cluster-slave-validity-factor",server.cluster_slave_validity_factor,REDIS_CLUSTER_DEFAULT_SLAVE_VALIDITY);
     rewriteConfigNumericalOption(state,"slowlog-log-slower-than",server.slowlog_log_slower_than,REDIS_SLOWLOG_LOG_SLOWER_THAN);
+    rewriteConfigNumericalOption(state,"latency-monitor-threshold",server.latency_monitor_threshold,REDIS_DEFAULT_LATENCY_MONITOR_THRESHOLD);
     rewriteConfigNumericalOption(state,"slowlog-max-len",server.slowlog_max_len,REDIS_SLOWLOG_MAX_LEN);
     rewriteConfigNotifykeyspaceeventsOption(state);
     rewriteConfigNumericalOption(state,"hash-max-ziplist-entries",server.hash_max_ziplist_entries,REDIS_HASH_MAX_ZIPLIST_ENTRIES);
-- 
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