From b29d54d0c2fa9c9faee08915342688916e4125a8 Mon Sep 17 00:00:00 2001
From: Konstantin Osipov <kostja@tarantool.org>
Date: Wed, 29 Jul 2015 16:29:29 +0300
Subject: [PATCH] log: fix a sever performance bug
Any function of Lua log module would first evaluate the call stack,
and only then invoke the logger function -- even if the text is
then sent to /dev/null because log level is too low.
Short cut the log call in case the log level is low and the message
is muted.
---
src/lua/log.lua | 5 +++++
src/say.cc | 9 ++++-----
src/say.h | 1 +
3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/src/lua/log.lua b/src/lua/log.lua
index ae638a2866..d086bcc6df 100644
--- a/src/lua/log.lua
+++ b/src/lua/log.lua
@@ -19,9 +19,14 @@ ffi.cdef[[
};
pid_t logger_pid;
+ extern int log_level;
]]
local function say(level, fmt, ...)
+ if ffi.C.log_level < level then
+-- don't waste cycles on debug.getinfo()
+ return
+ end
local debug = require('debug')
local str = string.format(tostring(fmt), ...)
local frame = debug.getinfo(3, "Sl")
diff --git a/src/say.cc b/src/say.cc
index ec96fddcf1..9935e91a96 100644
--- a/src/say.cc
+++ b/src/say.cc
@@ -48,8 +48,7 @@ pid_t logger_pid;
static bool booting = true;
static bool logger_background = true;
static const char *binary_filename;
-static int log_level_default = S_INFO;
-static int *log_level = &log_level_default;
+int log_level = S_INFO;
static void
sayf(int level, const char *filename, int line, const char *error,
@@ -89,7 +88,7 @@ say_init(const char *argv0)
void
say_set_log_level(int new_level)
{
- *log_level = new_level;
+ log_level = new_level;
}
/**
@@ -216,7 +215,7 @@ say_init_file()
void
say_logger_init(const char *path, int level, int nonblock, int background)
{
- *log_level = level;
+ log_level = level;
logger_nonblock = nonblock;
logger_background = background;
setvbuf(stderr, NULL, _IONBF, 0);
@@ -307,7 +306,7 @@ static void
sayf(int level, const char *filename, int line, const char *error, const char *format, ...)
{
int errsv = errno; /* Preserve the errno. */
- if (*log_level < level)
+ if (log_level < level)
return;
va_list ap;
va_start(ap, format);
diff --git a/src/say.h b/src/say.h
index c2f74ed9ec..1896958e92 100644
--- a/src/say.h
+++ b/src/say.h
@@ -52,6 +52,7 @@ enum say_level {
/** \endcond public */
extern int log_fd;
+extern int log_level;
extern pid_t logger_pid;
void
--
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