SectionProfiler.php

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<?php
use Wikimedia\ScopedCallback;
 
class SectionProfiler {
    protected $start;
    protected $end;
    protected $stack = [];
    protected $workStack = [];
 
    protected $collated = [];
    protected $collateDone = false;
 
    protected $collateOnly = true;
    protected $errorEntry;
 
    public function __construct( array $params = [] ) {
        $this->errorEntry = $this->getErrorEntry();
        $this->collateOnly = empty( $params['trace'] );
    }
 
    public function scopedProfileIn( $section ) {
        $this->profileInInternal( $section );
 
        return new SectionProfileCallback( $this, $section );
    }
 
    public function scopedProfileOut( ScopedCallback &$section ) {
        $section = null;
    }
 
    public function getFunctionStats() {
        $this->collateData();
 
        if ( is_array( $this->start ) && is_array( $this->end ) ) {
            $totalCpu = max( $this->end['cpu'] - $this->start['cpu'], 0 );
            $totalReal = max( $this->end['real'] - $this->start['real'], 0 );
            $totalMem = max( $this->end['memory'] - $this->start['memory'], 0 );
        } else {
            $totalCpu = 0;
            $totalReal = 0;
            $totalMem = 0;
        }
 
        $profile = [];
        foreach ( $this->collated as $fname => $data ) {
            $profile[] = [
                'name' => $fname,
                'calls' => $data['count'],
                'real' => $data['real'] * 1000,
                '%real' => $totalReal ? 100 * $data['real'] / $totalReal : 0,
                'cpu' => $data['cpu'] * 1000,
                '%cpu' => $totalCpu ? 100 * $data['cpu'] / $totalCpu : 0,
                'memory' => $data['memory'],
                '%memory' => $totalMem ? 100 * $data['memory'] / $totalMem : 0,
                'min_real' => 1000 * $data['min_real'],
                'max_real' => 1000 * $data['max_real']
            ];
        }
 
        $profile[] = [
            'name' => '-total',
            'calls' => 1,
            'real' => 1000 * $totalReal,
            '%real' => 100,
            'cpu' => 1000 * $totalCpu,
            '%cpu' => 100,
            'memory' => $totalMem,
            '%memory' => 100,
            'min_real' => 1000 * $totalReal,
            'max_real' => 1000 * $totalReal
        ];
 
        return $profile;
    }
 
    public function reset() {
        $this->start = null;
        $this->end = null;
        $this->stack = [];
        $this->workStack = [];
        $this->collated = [];
        $this->collateDone = false;
    }
 
    protected function getZeroEntry() {
        return [
            'cpu'      => 0.0,
            'real'     => 0.0,
            'memory'   => 0,
            'count'    => 0,
            'min_real' => 0.0,
            'max_real' => 0.0
        ];
    }
 
    protected function getErrorEntry() {
        $entry = $this->getZeroEntry();
        $entry['count'] = 1;
        return $entry;
    }
 
    protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) {
        $entry =& $this->collated[$name];
        if ( !is_array( $entry ) ) {
            $entry = $this->getZeroEntry();
            $this->collated[$name] =& $entry;
        }
        $entry['cpu'] += $elapsedCpu;
        $entry['real'] += $elapsedReal;
        $entry['memory'] += $memChange > 0 ? $memChange : 0;
        $entry['count']++;
        $entry['min_real'] = min( $entry['min_real'], $elapsedReal );
        $entry['max_real'] = max( $entry['max_real'], $elapsedReal );
    }
 
    public function profileInInternal( $functionname ) {
        // Once the data is collated for reports, any future calls
        // should clear the collation cache so the next report will
        // reflect them. This matters when trace mode is used.
        $this->collateDone = false;
 
        $cpu = $this->getTime( 'cpu' );
        $real = $this->getTime( 'wall' );
        $memory = memory_get_usage();
 
        if ( $this->start === null ) {
            $this->start = [ 'cpu' => $cpu, 'real' => $real, 'memory' => $memory ];
        }
 
        $this->workStack[] = [
            $functionname,
            count( $this->workStack ),
            $real,
            $cpu,
            $memory
        ];
    }
 
    public function profileOutInternal( $functionname ) {
        $item = array_pop( $this->workStack );
        if ( $item === null ) {
            $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
            return;
        }
        list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;
 
        if ( $functionname === 'close' ) {
            $message = "Profile section ended by close(): {$ofname}";
            $this->debugGroup( 'profileerror', $message );
            if ( $this->collateOnly ) {
                $this->collated[$message] = $this->errorEntry;
            } else {
                $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
            }
            $functionname = $ofname;
        } elseif ( $ofname !== $functionname ) {
            $message = "Profiling error: in({$ofname}), out($functionname)";
            $this->debugGroup( 'profileerror', $message );
            if ( $this->collateOnly ) {
                $this->collated[$message] = $this->errorEntry;
            } else {
                $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
            }
        }
 
        $realTime = $this->getTime( 'wall' );
        $cpuTime = $this->getTime( 'cpu' );
        $memUsage = memory_get_usage();
 
        if ( $this->collateOnly ) {
            $elapsedcpu = $cpuTime - $octime;
            $elapsedreal = $realTime - $ortime;
            $memchange = $memUsage - $omem;
            $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
        } else {
            $this->stack[] = array_merge( $item, [ $realTime, $cpuTime, $memUsage ] );
        }
 
        $this->end = [
            'cpu'      => $cpuTime,
            'real'     => $realTime,
            'memory'   => $memUsage
        ];
    }
 
    public function getCallTreeReport() {
        if ( $this->collateOnly ) {
            throw new Exception( "Tree is only available for trace profiling." );
        }
        return implode( '', array_map(
            [ $this, 'getCallTreeLine' ], $this->remapCallTree( $this->stack )
        ) );
    }
 
    protected function remapCallTree( array $stack ) {
        if ( count( $stack ) < 2 ) {
            return $stack;
        }
        $outputs = [];
        for ( $max = count( $stack ) - 1; $max > 0; ) {
            /* Find all items under this entry */
            $level = $stack[$max][1];
            $working = [];
            for ( $i = $max - 1; $i >= 0; $i-- ) {
                if ( $stack[$i][1] > $level ) {
                    $working[] = $stack[$i];
                } else {
                    break;
                }
            }
            $working = $this->remapCallTree( array_reverse( $working ) );
            $output = [];
            foreach ( $working as $item ) {
                array_push( $output, $item );
            }
            array_unshift( $output, $stack[$max] );
            $max = $i;
 
            array_unshift( $outputs, $output );
        }
        $final = [];
        foreach ( $outputs as $output ) {
            foreach ( $output as $item ) {
                $final[] = $item;
            }
        }
        return $final;
    }
 
    protected function getCallTreeLine( $entry ) {
        // $entry has (name, level, stime, scpu, smem, etime, ecpu, emem)
        list( $fname, $level, $startreal, , , $endreal ) = $entry;
        $delta = $endreal - $startreal;
        $space = str_repeat( ' ', $level );
        # The ugly double sprintf is to work around a PHP bug,
        # which has been fixed in recent releases.
        return sprintf( "%10s %s %s\n",
            trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
    }
 
    protected function collateData() {
        if ( $this->collateDone ) {
            return;
        }
        $this->collateDone = true;
        // Close opened profiling sections
        while ( count( $this->workStack ) ) {
            $this->profileOutInternal( 'close' );
        }
 
        if ( $this->collateOnly ) {
            return; // already collated as methods exited
        }
 
        $this->collated = [];
 
        # Estimate profiling overhead
        $oldEnd = $this->end;
        $profileCount = count( $this->stack );
        $this->calculateOverhead( $profileCount );
 
        # First, subtract the overhead!
        $overheadTotal = $overheadMemory = $overheadInternal = [];
        foreach ( $this->stack as $entry ) {
            // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
            $fname = $entry[0];
            $elapsed = $entry[5] - $entry[2];
            $memchange = $entry[7] - $entry[4];
 
            if ( $fname === '-overhead-total' ) {
                $overheadTotal[] = $elapsed;
                $overheadMemory[] = max( 0, $memchange );
            } elseif ( $fname === '-overhead-internal' ) {
                $overheadInternal[] = $elapsed;
            }
        }
        $overheadTotal = $overheadTotal ?
            array_sum( $overheadTotal ) / count( $overheadInternal ) : 0;
        $overheadMemory = $overheadMemory ?
            array_sum( $overheadMemory ) / count( $overheadInternal ) : 0;
        $overheadInternal = $overheadInternal ?
            array_sum( $overheadInternal ) / count( $overheadInternal ) : 0;
 
        # Collate
        foreach ( $this->stack as $index => $entry ) {
            // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
            $fname = $entry[0];
            $elapsedCpu = $entry[6] - $entry[3];
            $elapsedReal = $entry[5] - $entry[2];
            $memchange = $entry[7] - $entry[4];
            $subcalls = $this->calltreeCount( $this->stack, $index );
 
            if ( substr( $fname, 0, 9 ) !== '-overhead' ) {
                # Adjust for profiling overhead (except special values with elapsed=0)
                if ( $elapsed ) {
                    $elapsed -= $overheadInternal;
                    $elapsed -= ( $subcalls * $overheadTotal );
                    $memchange -= ( $subcalls * $overheadMemory );
                }
            }
 
            $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange );
        }
 
        $this->collated['-overhead-total']['count'] = $profileCount;
        arsort( $this->collated, SORT_NUMERIC );
 
        // Unclobber the end info map (the overhead checking alters it)
        $this->end = $oldEnd;
    }
 
    protected function calculateOverhead( $profileCount ) {
        $this->profileInInternal( '-overhead-total' );
        for ( $i = 0; $i < $profileCount; $i++ ) {
            $this->profileInInternal( '-overhead-internal' );
            $this->profileOutInternal( '-overhead-internal' );
        }
        $this->profileOutInternal( '-overhead-total' );
    }
 
    protected function calltreeCount( $stack, $start ) {
        $level = $stack[$start][1];
        $count = 0;
        for ( $i = $start - 1; $i >= 0 && $stack[$i][1] > $level; $i-- ) {
            $count++;
        }
        return $count;
    }
 
    protected function getTime( $metric = 'wall' ) {
        if ( $metric === 'cpu' || $metric === 'user' ) {
            $ru = getrusage( 0 /* RUSAGE_SELF */ );
            $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
            if ( $metric === 'cpu' ) {
                # This is the time of system calls, added to the user time
                # it gives the total CPU time
                $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
            }
            return $time;
        } else {
            return microtime( true );
        }
    }
 
    protected function debug( $s ) {
        if ( function_exists( 'wfDebug' ) ) {
            wfDebug( $s );
        }
    }
 
    protected function debugGroup( $group, $s ) {
        if ( function_exists( 'wfDebugLog' ) ) {
            wfDebugLog( $group, $s );
        }
    }
}