From d3efe04c4731bda4657b80f099f8bcaca3c26319 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Mon, 24 Mar 2014 10:00:08 +0100
Subject: [PATCH] Cache uname() output across INFO calls.

Uname was profiled to be a slow syscall. It produces always the same
output in the context of a single execution of Redis, so calling it at
every INFO output generation does not make too much sense.

The uname utsname structure was modified as a static variable. At the
same time a static integer was added to check if we need to call uname
the first time.
---
 src/redis.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/redis.c b/src/redis.c
index c2a858fd..30816825 100644
--- a/src/redis.c
+++ b/src/redis.c
@@ -2359,7 +2359,8 @@ sds genRedisInfoString(char *section) {
 
     /* Server */
     if (allsections || defsections || !strcasecmp(section,"server")) {
-        struct utsname name;
+        static int call_uname = 1;
+        static struct utsname name;
         char *mode;
 
         if (server.cluster_enabled) mode = "cluster";
@@ -2367,7 +2368,13 @@ sds genRedisInfoString(char *section) {
         else mode = "standalone";
     
         if (sections++) info = sdscat(info,"\r\n");
-        uname(&name);
+
+        if (call_uname) {
+            /* Uname can be slow and is always the same output. Cache it. */
+            uname(&name);
+            call_uname = 0;
+        }
+
         info = sdscatprintf(info,
             "# Server\r\n"
             "redis_version:%s\r\n"