From a329463655af8bc3e286f50c437727f21865b550 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Wed, 23 Aug 2017 11:24:47 +0200 Subject: [PATCH] OPTIM: lua: don't use expensive functions to parse headers in the HTTP applet In the HTTP applet, we have to parse the response headers provided by the application and to produce a response. strcasecmp() is expensive, and chunk_append() even more as it uses a format string. Here we check the string length before calling strcasecmp(), which results in strcasecmp() being called only on the relevant header in practise due to very few collisions on the name lengths, effectively dividing the number of calls by 3, and we replace chunk_appendf() with memcpy() as we already know the string lengths. Doing just this makes the "hello-world" applet 5% faster, reaching 41400 requests/s on a core i5-3320M. --- src/hlua.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/src/hlua.c b/src/hlua.c index 349d3724f..503675bad 100644 --- a/src/hlua.c +++ b/src/hlua.c @@ -4196,7 +4196,9 @@ __LJMP static int hlua_applet_http_start_response(lua_State *L) struct chunk *tmp = get_trash_chunk(); struct hlua_appctx *appctx = MAY_LJMP(hlua_checkapplet_http(L, 1)); const char *name; + size_t name_len; const char *value; + size_t value_len; int id; int hdr_connection = 0; long long hdr_contentlength = -1; @@ -4231,7 +4233,7 @@ __LJMP static int hlua_applet_http_start_response(lua_State *L) lua_typename(L, lua_type(L, -2))); WILL_LJMP(lua_error(L)); } - name = lua_tostring(L, -2); + name = lua_tolstring(L, -2, &name_len); /* We expect an array as -1. */ if (lua_type(L, -1) != LUA_TTABLE) { @@ -4264,15 +4266,25 @@ __LJMP static int hlua_applet_http_start_response(lua_State *L) lua_typename(L, lua_type(L, -1))); WILL_LJMP(lua_error(L)); } - value = lua_tostring(L, -1); + value = lua_tolstring(L, -1, &value_len); /* Catenate a new header. */ - chunk_appendf(tmp, "%s: %s\r\n", name, value); + if (tmp->len + name_len + 2 + value_len + 2 < tmp->size) { + memcpy(tmp->str + tmp->len, name, name_len); + tmp->len += name_len; + tmp->str[tmp->len++] = ':'; + tmp->str[tmp->len++] = ' '; + + memcpy(tmp->str + tmp->len, value, value_len); + tmp->len += value_len; + tmp->str[tmp->len++] = '\r'; + tmp->str[tmp->len++] = '\n'; + } /* Protocol checks. */ /* Check if the header conneciton is present. */ - if (strcasecmp("connection", name) == 0) + if (name_len == 10 && strcasecmp("connection", name) == 0) hdr_connection = 1; /* Copy the header content length. The length conversion @@ -4280,11 +4292,12 @@ __LJMP static int hlua_applet_http_start_response(lua_State *L) * the content-length remains negative so that we can * switch to either chunked encoding or close. */ - if (strcasecmp("content-length", name) == 0) + if (name_len == 14 && strcasecmp("content-length", name) == 0) strl2llrc(value, strlen(value), &hdr_contentlength); /* Check if the client annouces a transfer-encoding chunked it self. */ - if (strcasecmp("transfer-encoding", name) == 0 && + if (name_len == 17 && value_len == 7 && + strcasecmp("transfer-encoding", name) == 0 && strcasecmp("chunked", value) == 0) hdr_chunked = 1;