From de1c74879b0f54a33c90145c606309a3d1318ce5 Mon Sep 17 00:00:00 2001
From: filipe oliveira <filipecosta.90@gmail.com>
Date: Wed, 30 Nov 2022 20:08:12 +0000
Subject: [PATCH] changing addReplySds and sdscat to addReplyStatusLength()
 within luaReplyToRedisReply() (#11556)

profiling EVALSHA\ we see that luaReplyToRedisReply takes 8.73% out of the
56.90% of luaCallFunction CPU cycles.

Using addReplyStatusLength instead of directly composing the protocol to avoid
sdscatprintf and addReplySds ( which imply multiple sdslen calls ).

The new approach drops
luaReplyToRedisReply CPU cycles to 3.77%
---
 src/script_lua.c | 2 +-
 src/server.h     | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/script_lua.c b/src/script_lua.c
index c8e6a1283361..578a2206751d 100644
--- a/src/script_lua.c
+++ b/src/script_lua.c
@@ -653,7 +653,7 @@ static void luaReplyToRedisReply(client *c, client* script_client, lua_State *lu
         if (t == LUA_TSTRING) {
             sds ok = sdsnew(lua_tostring(lua,-1));
             sdsmapchars(ok,"\r\n","  ",2);
-            addReplySds(c,sdscatprintf(sdsempty(),"+%s\r\n",ok));
+            addReplyStatusLength(c, ok, sdslen(ok));
             sdsfree(ok);
             lua_pop(lua,2);
             return;
diff --git a/src/server.h b/src/server.h
index 9dfbf81b7aed..105b2db4e628 100644
--- a/src/server.h
+++ b/src/server.h
@@ -2507,6 +2507,7 @@ void addReplyBulkCString(client *c, const char *s);
 void addReplyBulkCBuffer(client *c, const void *p, size_t len);
 void addReplyBulkLongLong(client *c, long long ll);
 void addReply(client *c, robj *obj);
+void addReplyStatusLength(client *c, const char *s, size_t len);
 void addReplySds(client *c, sds s);
 void addReplyBulkSds(client *c, sds s);
 void setDeferredReplyBulkSds(client *c, void *node, sds s);