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Optimise no-op debug logging in LegacyLogger

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Reduce the cost of calling LegacyLogger::debug() when there is no debug
log enabled (the normal production case) from 0.8µs to 0.2µs, measured
locally, by duplicating some of the logic from log() and shouldEmit() to
derive a constant "minimum level".

I also introduced constants for the integers, to avoid unnecessary
lookups in self::$levelMapping, and I introduced $this->isDB, to avoid a
hashtable lookup in log(). I fixed a typo in a comment, and removed
"@return null", which was confusing PHPStorm.

Change-Id: I9fc37b8062ff22f85feda9a05821e3d8c9688519
This commit is contained in:
Tim Starling 2019-11-20 15:49:29 +11:00
parent 8d240f87a9
commit a4ae47a7b7
1 changed files with 64 additions and 15 deletions
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79
includes/debug/logger/LegacyLogger.php
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@ -55,21 +55,31 @@ class LegacyLogger extends AbstractLogger {
*/
protected $channel;
private const LEVEL_DEBUG = 100;
private const LEVEL_INFO = 200;
private const LEVEL_NOTICE = 250;
private const LEVEL_WARNING = 300;
private const LEVEL_ERROR = 400;
private const LEVEL_CRITICAL = 500;
private const LEVEL_ALERT = 550;
private const LEVEL_EMERGENCY = 600;
private const LEVEL_INFINITY = 999;
/**
* Convert \Psr\Log\LogLevel constants into int for sane comparisons
* These are the same values that Monlog uses
* These are the same values that Monolog uses
*
* @var array $levelMapping
*/
protected static $levelMapping = [
LogLevel::DEBUG => 100,
LogLevel::INFO => 200,
LogLevel::NOTICE => 250,
LogLevel::WARNING => 300,
LogLevel::ERROR => 400,
LogLevel::CRITICAL => 500,
LogLevel::ALERT => 550,
LogLevel::EMERGENCY => 600,
LogLevel::DEBUG => self::LEVEL_DEBUG,
LogLevel::INFO => self::LEVEL_INFO,
LogLevel::NOTICE => self::LEVEL_NOTICE,
LogLevel::WARNING => self::LEVEL_WARNING,
LogLevel::ERROR => self::LEVEL_ERROR,
LogLevel::CRITICAL => self::LEVEL_CRITICAL,
LogLevel::ALERT => self::LEVEL_ALERT,
LogLevel::EMERGENCY => self::LEVEL_EMERGENCY,
];
/**
@ -80,11 +90,50 @@ class LegacyLogger extends AbstractLogger {
'DBConnection' => true
];
/**
* Minimum level. This is just to allow faster discard of debugging
* messages. Not all messages meeting the level will be logged.
*
* @var int
*/
private $minimumLevel;
/**
* Whether the channel is a DB channel
*
* @var bool
*/
private $isDB;
/**
* @param string $channel
*/
public function __construct( $channel ) {
global $wgDebugLogFile, $wgDBerrorLog, $wgDebugLogGroups, $wgDebugToolbar;
$this->channel = $channel;
$this->isDB = isset( self::$dbChannels[$channel] );
// Calculate minimum level, duplicating some of the logic from log() and shouldEmit()
if ( $wgDebugLogFile != '' || $wgDebugToolbar ) {
// Log all messages if there is a debug log file or debug toolbar
$this->minimumLevel = self::LEVEL_DEBUG;
} elseif ( isset( $wgDebugLogGroups[$channel] ) ) {
$logConfig = $wgDebugLogGroups[$channel];
// Log messages if the config is set, according to the configured level
if ( is_array( $logConfig ) && isset( $logConfig['level'] ) ) {
$this->minimumLevel = self::$levelMapping[$logConfig['level']];
} else {
$this->minimumLevel = self::LEVEL_DEBUG;
}
} else {
// No other case hit: discard all messages
$this->minimumLevel = self::LEVEL_INFINITY;
}
if ( $this->isDB && $wgDBerrorLog && $this->minimumLevel > self::LEVEL_ERROR ) {
// Log DB errors if there is a DB error log
$this->minimumLevel = self::LEVEL_ERROR;
}
}
/**
@ -93,7 +142,6 @@ class LegacyLogger extends AbstractLogger {
* @param string|int $level
* @param string $message
* @param array $context
* @return null
*/
public function log( $level, $message, array $context = [] ) {
global $wgDBerrorLog;
@ -101,8 +149,12 @@ class LegacyLogger extends AbstractLogger {
if ( is_string( $level ) ) {
$level = self::$levelMapping[$level];
}
if ( $level < $this->minimumLevel ) {
return;
}
if ( $this->channel === 'DBQuery'
&& $level === self::$levelMapping[LogLevel::DEBUG]
&& $level === self::LEVEL_DEBUG
&& isset( $context['sql'] )
) {
// Also give the query information to the MWDebug tools
@ -124,10 +176,7 @@ class LegacyLogger extends AbstractLogger {
// Likewise, if the site does not use $wgDBerrorLog, it should
// configurable like any other channel via $wgDebugLogGroups
// or $wgMWLoggerDefaultSpi.
if ( isset( self::$dbChannels[$this->channel] )
&& $level >= self::$levelMapping[LogLevel::ERROR]
&& $wgDBerrorLog
) {
if ( $this->isDB && $level >= self::LEVEL_ERROR && $wgDBerrorLog ) {
// Format and write DB errors to the legacy locations
$effectiveChannel = 'wfLogDBError';
} else {