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[mediawiki.git] / includes / profiler / ProfilerStandard.php

<?php
/**
 * Common implementation class for profiling.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Profiler
 */

/**
 * Standard profiler that tracks real time, cpu time, and memory deltas
 *
 * This supports profile reports, the debug toolbar, and high-contention
 * DB query warnings. This does not persist the profiling data though.
 *
 * @ingroup Profiler
 * @since 1.24
 */
class ProfilerStandard extends Profiler {
        /** @var array List of resolved profile calls with start/end data */
        protected $stack = array();
        /** @var array Queue of open profile calls with start data */
        protected $workStack = array();

        /** @var array Map of (function name => aggregate data array) */
        protected $collated = array();
        /** @var bool */
        protected $collateDone = false;
        /** @var bool Whether to collect the full stack trace or just aggregates */
        protected $collateOnly = true;
        /** @var array Cache of a standard broken collation entry */
        protected $errorEntry;

        /**
         * @param array $params
         *   - initTotal : set to false to omit -total/-setup entries (which use request start time)
         */
        public function __construct( array $params ) {
                parent::__construct( $params );

                if ( !isset( $params['initTotal'] ) || $params['initTotal'] ) {
                        $this->addInitialStack();
                }
        }

        /**
         * Return whether this a stub profiler
         *
         * @return bool
         */
        public function isStub() {
                return false;
        }

        /**
         * Add the inital item in the stack.
         */
        protected function addInitialStack() {
                $this->errorEntry = $this->getErrorEntry();

                $initialTime = $this->getInitialTime( 'wall' );
                $initialCpu = $this->getInitialTime( 'cpu' );
                if ( $initialTime !== null && $initialCpu !== null ) {
                        $this->workStack[] = array( '-total', 0, $initialTime, $initialCpu, 0 );
                        if ( $this->collateOnly ) {
                                $this->workStack[] = array( '-setup', 1, $initialTime, $initialCpu, 0 );
                                $this->profileOut( '-setup' );
                        } else {
                                $this->stack[] = array( '-setup', 1, $initialTime, $initialCpu, 0,
                                        $this->getTime( 'wall' ), $this->getTime( 'cpu' ), 0 );
                        }
                } else {
                        $this->profileIn( '-total' );
                }
        }

        /**
         * @return array Initial collation entry
         */
        protected function getZeroEntry() {
                return array(
                        'cpu'      => 0.0,
                        'cpu_sq'   => 0.0,
                        'real'     => 0.0,
                        'real_sq'  => 0.0,
                        'memory'   => 0,
                        'count'    => 0,
                        'min_cpu'  => 0.0,
                        'max_cpu'  => 0.0,
                        'min_real' => 0.0,
                        'max_real' => 0.0,
                        'periods'  => array(), // not filled if collateOnly
                        'overhead' => 0 // not filled if collateOnly
                );
        }

        /**
         * @return array Initial collation entry for errors
         */
        protected function getErrorEntry() {
                $entry = $this->getZeroEntry();
                $entry['count'] = 1;
                return $entry;
        }

        /**
         * Update the collation entry for a given method name
         *
         * @param string $name
         * @param float $elapsedCpu
         * @param float $elapsedReal
         * @param int $memChange
         * @param int $subcalls
         * @param array|null $period Map of ('start','end','memory','subcalls')
         */
        protected function updateEntry(
                $name, $elapsedCpu, $elapsedReal, $memChange, $subcalls = 0, $period = null
        ) {
                $entry =& $this->collated[$name];
                if ( !is_array( $entry ) ) {
                        $entry = $this->getZeroEntry();
                        $this->collated[$name] =& $entry;
                }
                $entry['cpu'] += $elapsedCpu;
                $entry['cpu_sq'] += $elapsedCpu * $elapsedCpu;
                $entry['real'] += $elapsedReal;
                $entry['real_sq'] += $elapsedReal * $elapsedReal;
                $entry['memory'] += $memChange > 0 ? $memChange : 0;
                $entry['count']++;
                $entry['min_cpu'] = $elapsedCpu < $entry['min_cpu'] ? $elapsedCpu : $entry['min_cpu'];
                $entry['max_cpu'] = $elapsedCpu > $entry['max_cpu'] ? $elapsedCpu : $entry['max_cpu'];
                $entry['min_real'] = $elapsedReal < $entry['min_real'] ? $elapsedReal : $entry['min_real'];
                $entry['max_real'] = $elapsedReal > $entry['max_real'] ? $elapsedReal : $entry['max_real'];
                // Apply optional fields
                $entry['overhead'] += $subcalls;
                if ( $period ) {
                        $entry['periods'][] = $period;
                }
        }

        /**
         * Called by wfProfieIn()
         *
         * @param string $functionname
         */
        public function profileIn( $functionname ) {
                global $wgDebugFunctionEntry;

                if ( $wgDebugFunctionEntry ) {
                        $this->debug( str_repeat( ' ', count( $this->workStack ) ) .
                                'Entering ' . $functionname . "\n" );
                }

                $this->workStack[] = array(
                        $functionname,
                        count( $this->workStack ),
                        $this->getTime( 'time' ),
                        $this->getTime( 'cpu' ),
                        memory_get_usage()
                );
        }

        /**
         * Called by wfProfieOut()
         *
         * @param string $functionname
         */
        public function profileOut( $functionname ) {
                global $wgDebugFunctionEntry;

                if ( $wgDebugFunctionEntry ) {
                        $this->debug( str_repeat( ' ', count( $this->workStack ) - 1 ) .
                                'Exiting ' . $functionname . "\n" );
                }

                $item = array_pop( $this->workStack );
                list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;

                if ( $item === null ) {
                        $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
                } else {
                        if ( $functionname === 'close' ) {
                                if ( $ofname !== '-total' ) {
                                        $message = "Profile section ended by close(): {$ofname}";
                                        $this->debugGroup( 'profileerror', $message );
                                        if ( $this->collateOnly ) {
                                                $this->collated[$message] = $this->errorEntry;
                                        } else {
                                                $this->stack[] = array( $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[] = array( $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 );
                                }
                        }
                        $realTime = $this->getTime( 'wall' );
                        $cpuTime = $this->getTime( 'cpu' );
                        if ( $this->collateOnly ) {
                                $elapsedcpu = $cpuTime - $octime;
                                $elapsedreal = $realTime - $ortime;
                                $memchange = memory_get_usage() - $omem;
                                $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
                        } else {
                                $this->stack[] = array_merge( $item,
                                        array( $realTime, $cpuTime,     memory_get_usage() ) );
                        }
                }
        }

        public function scopedProfileIn( $section ) {
                $this->profileIn( $section );

                $that = $this;
                return new ScopedCallback( function() use ( $that, $section ) {
                        $that->profileOut( $section );
                } );
        }

        /**
         * Close opened profiling sections
         */
        public function close() {
                while ( count( $this->workStack ) ) {
                        $this->profileOut( 'close' );
                }
        }

        /**
         * Returns a profiling output to be stored in debug file
         *
         * @return string
         */
        public function getOutput() {
                global $wgDebugFunctionEntry, $wgProfileCallTree;

                $wgDebugFunctionEntry = false; // hack

                if ( !count( $this->stack ) && !count( $this->collated ) ) {
                        return "No profiling output\n";
                }

                if ( $wgProfileCallTree ) {
                        return $this->getCallTree();
                } else {
                        return $this->getFunctionReport();
                }
        }

        /**
         * Returns a tree of function call instead of a list of functions
         * @return string
         */
        protected function getCallTree() {
                return implode( '', array_map(
                        array( &$this, 'getCallTreeLine' ), $this->remapCallTree( $this->stack )
                ) );
        }

        /**
         * Recursive function the format the current profiling array into a tree
         *
         * @param array $stack Profiling array
         * @return array
         */
        protected function remapCallTree( array $stack ) {
                if ( count( $stack ) < 2 ) {
                        return $stack;
                }
                $outputs = array();
                for ( $max = count( $stack ) - 1; $max > 0; ) {
                        /* Find all items under this entry */
                        $level = $stack[$max][1];
                        $working = array();
                        for ( $i = $max -1; $i >= 0; $i-- ) {
                                if ( $stack[$i][1] > $level ) {
                                        $working[] = $stack[$i];
                                } else {
                                        break;
                                }
                        }
                        $working = $this->remapCallTree( array_reverse( $working ) );
                        $output = array();
                        foreach ( $working as $item ) {
                                array_push( $output, $item );
                        }
                        array_unshift( $output, $stack[$max] );
                        $max = $i;

                        array_unshift( $outputs, $output );
                }
                $final = array();
                foreach ( $outputs as $output ) {
                        foreach ( $output as $item ) {
                                $final[] = $item;
                        }
                }
                return $final;
        }

        /**
         * Callback to get a formatted line for the call tree
         * @param array $entry
         * @return string
         */
        protected function getCallTreeLine( $entry ) {
                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 );
        }

        /**
         * Return the collated data, collating first if need be
         * @return array
         */
        public function getCollatedData() {
                if ( !$this->collateDone ) {
                        $this->collateData();
                }
                return $this->collated;
        }

        /**
         * Populate collated
         */
        protected function collateData() {
                if ( $this->collateDone ) {
                        return;
                }
                $this->collateDone = true;
                $this->close(); // set "-total" entry

                if ( $this->collateOnly ) {
                        return; // already collated as methods exited
                }

                $this->collated = array();

                # Estimate profiling overhead
                $profileCount = count( $this->stack );
                self::calculateOverhead( $profileCount );

                # First, subtract the overhead!
                $overheadTotal = $overheadMemory = $overheadInternal = array();
                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 );
                                }
                        }

                        $period = array( 'start' => $entry[2], 'end' => $entry[5],
                                'memory' => $memchange, 'subcalls' => $subcalls );
                        $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange, $subcalls, $period );
                }

                $this->collated['-overhead-total']['count'] = $profileCount;
                arsort( $this->collated, SORT_NUMERIC );
        }

        /**
         * Returns a list of profiled functions.
         *
         * @return string
         */
        protected function getFunctionReport() {
                $this->collateData();

                $width = 140;
                $nameWidth = $width - 65;
                $format = "%-{$nameWidth}s %6d %13.3f %13.3f %13.3f%% %9d  (%13.3f -%13.3f) [%d]\n";
                $titleFormat = "%-{$nameWidth}s %6s %13s %13s %13s %9s\n";
                $prof = "\nProfiling data\n";
                $prof .= sprintf( $titleFormat, 'Name', 'Calls', 'Total', 'Each', '%', 'Mem' );

                $total = isset( $this->collated['-total'] )
                        ? $this->collated['-total']['real']
                        : 0;

                foreach ( $this->collated as $fname => $data ) {
                        $calls = $data['count'];
                        $percent = $total ? 100 * $data['real'] / $total : 0;
                        $memory = $data['memory'];
                        $prof .= sprintf( $format,
                                substr( $fname, 0, $nameWidth ),
                                $calls,
                                (float)( $data['real'] * 1000 ),
                                (float)( $data['real'] * 1000 ) / $calls,
                                $percent,
                                $memory,
                                ( $data['min_real'] * 1000.0 ),
                                ( $data['max_real'] * 1000.0 ),
                                $data['overhead']
                        );
                }
                $prof .= "\nTotal: $total\n\n";

                return $prof;
        }

        public function getFunctionStats() {
                // This method is called before shutdown in the footer method on Skins.
                // If some outer methods have not yet called wfProfileOut(), work around
                // that by clearing anything in the work stack to just the "-total" entry.
                // Collate after doing this so the results do not include profile errors.
                if ( count( $this->workStack ) > 1 ) {
                        $oldWorkStack = $this->workStack;
                        $this->workStack = array( $this->workStack[0] ); // just the "-total" one
                } else {
                        $oldWorkStack = null;
                }
                $this->collateData();
                // If this trick is used, then the old work stack is swapped back afterwards
                // and collateDone is reset to false. This means that logData() will still
                // make use of all the method data since the missing wfProfileOut() calls
                // should be made by the time it is called.
                if ( $oldWorkStack ) {
                        $this->workStack = $oldWorkStack;
                        $this->collateDone = false;
                }

                $totalCpu = isset( $this->collated['-total'] )
                        ? $this->collated['-total']['cpu']
                        : 0;
                $totalReal = isset( $this->collated['-total'] )
                        ? $this->collated['-total']['real']
                        : 0;
                $totalMem = isset( $this->collated['-total'] )
                        ? $this->collated['-total']['memory']
                        : 0;

                $profile = array();
                foreach ( $this->collated as $fname => $data ) {
                        $profile[] = array(
                                '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' => $data['min_real'] * 1000,
                                'max' => $data['max_real'] * 1000
                        );
                }

                return $profile;
        }

        /**
         * Dummy calls to wfProfileIn/wfProfileOut to calculate its overhead
         * @param int $profileCount
         */
        protected static function calculateOverhead( $profileCount ) {
                wfProfileIn( '-overhead-total' );
                for ( $i = 0; $i < $profileCount; $i++ ) {
                        wfProfileIn( '-overhead-internal' );
                        wfProfileOut( '-overhead-internal' );
                }
                wfProfileOut( '-overhead-total' );
        }

        /**
         * Counts the number of profiled function calls sitting under
         * the given point in the call graph. Not the most efficient algo.
         *
         * @param array $stack
         * @param int $start
         * @return int
         */
        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;
        }

        /**
         * Get the initial time of the request, based either on $wgRequestTime or
         * $wgRUstart. Will return null if not able to find data.
         *
         * @param string|bool $metric Metric to use, with the following possibilities:
         *   - user: User CPU time (without system calls)
         *   - cpu: Total CPU time (user and system calls)
         *   - wall (or any other string): elapsed time
         *   - false (default): will fall back to default metric
         * @return float|null
         */
        protected function getTime( $metric = 'wall' ) {
                if ( $metric === 'cpu' || $metric === 'user' ) {
                        $ru = wfGetRusage();
                        if ( !$ru ) {
                                return 0;
                        }
                        $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 );
                }
        }

        /**
         * Get the initial time of the request, based either on $wgRequestTime or
         * $wgRUstart. Will return null if not able to find data.
         *
         * @param string|bool $metric Metric to use, with the following possibilities:
         *   - user: User CPU time (without system calls)
         *   - cpu: Total CPU time (user and system calls)
         *   - wall (or any other string): elapsed time
         *   - false (default): will fall back to default metric
         * @return float|null
         */
        protected function getInitialTime( $metric = 'wall' ) {
                global $wgRequestTime, $wgRUstart;

                if ( $metric === 'cpu' || $metric === 'user' ) {
                        if ( !count( $wgRUstart ) ) {
                                return null;
                        }

                        $time = $wgRUstart['ru_utime.tv_sec'] + $wgRUstart['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 += $wgRUstart['ru_stime.tv_sec'] + $wgRUstart['ru_stime.tv_usec'] / 1e6;
                        }
                        return $time;
                } else {
                        if ( empty( $wgRequestTime ) ) {
                                return null;
                        } else {
                                return $wgRequestTime;
                        }
                }
        }

        /**
         * Add an entry in the debug log file
         *
         * @param string $s String to output
         */
        protected function debug( $s ) {
                if ( function_exists( 'wfDebug' ) ) {
                        wfDebug( $s );
                }
        }

        /**
         * Add an entry in the debug log group
         *
         * @param string $group Group to send the message to
         * @param string $s String to output
         */
        protected function debugGroup( $group, $s ) {
                if ( function_exists( 'wfDebugLog' ) ) {
                        wfDebugLog( $group, $s );
                }
        }
}