wikimedia/mediawiki-core

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includes/profiler/ProfilerXhprof.php

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<?php
/**
 * Copyright 2014 Wikimedia Foundation and contributors
 *
 * 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
 */

/**
 * Profiler that captures all function calls from the XHProf PHP extension.
 *
 * This extension can be installed via PECL or your operating system's package manager.
 * This also supports the Tideways-XHProf PHP extension.
 *
 * @ingroup Profiler
 * @see $wgProfiler
 * @see https://php.net/xhprof
 * @see https://github.com/tideways/php-xhprof-extension
 */
class ProfilerXhprof extends Profiler {
    /**
     * @var XhprofData|null
     */
    protected $xhprofData;

    /**
     * Profiler for explicit, arbitrary, frame labels
     * @var SectionProfiler
     */
    protected $sprofiler;

    /**
     * @see $wgProfiler
     * @param array $params Associative array of parameters:
     *  - int flags: Bitmask of constants from the XHProf or Tideways-XHProf extension
     *    that will be passed to its enable function,
     *    such as `XHPROF_FLAGS_CPU | XHPROF_FLAGS_MEMORY | XHPROF_FLAGS_NO_BUILTINS`.
     *    With Tideways-XHProf, use `TIDEWAYS_XHPROF_FLAGS_*` instead.
     *  - bool running: If true, it is assumed that the enable function was already
     *    called. The `flags` option is ignored in this case.
     *    This exists for use with a custom web entrypoint from which the profiler
     *    is started before MediaWiki is included.
     *  - array include: If set, only function names matching a pattern in this
     *    array will be reported. The pattern strings will be matched using
     *    the PHP fnmatch() function.
     *  - array exclude: If set, function names matching an exact name in this
     *    will be skipped over by XHProf. Ignored functions become transparent
     *    in the profile. For example, `foo=>ignored=>bar` becomes `foo=>bar`.
     *    This option is backed by XHProf's `ignored_functions` option.
     *
     *    **Note:** The `exclude` option is not supported in Tideways-XHProf.
     */
    public function __construct( array $params = [] ) {
        parent::__construct( $params );

        // See T180183 and T247332 for why we need the 'running' option.
        if ( empty( $params['running'] ) ) {
            $flags = $params['flags'] ?? 0;
            if ( function_exists( 'xhprof_enable' ) ) {
                $options = isset( $params['exclude'] )
                    ? [ 'ignored_functions' => $params['exclude'] ]
                    : [];
                xhprof_enable( $flags, $options );
            } elseif ( function_exists( 'tideways_xhprof_enable' ) ) {
                if ( isset( $params['exclude'] ) ) {
                    throw new RuntimeException( 'The exclude option is not supported in tideways_xhprof' );
                }
                tideways_xhprof_enable( $flags );
            } else {
                throw new RuntimeException( 'Neither xhprof nor tideways_xhprof is installed' );
            }
        }

        $this->sprofiler = new SectionProfiler();
    }

    /**
     * @return XhprofData
     */
    public function getXhprofData() {
        if ( !$this->xhprofData ) {
            if ( function_exists( 'xhprof_disable' ) ) {
                $data = xhprof_disable();
            } elseif ( function_exists( 'tideways_xhprof_disable' ) ) {
                $data = tideways_xhprof_disable();
            } else {
                throw new RuntimeException( 'Neither xhprof nor tideways_xhprof is installed' );
            }
            $this->xhprofData = new XhprofData( $data, $this->params );
        }
        return $this->xhprofData;
    }

    public function scopedProfileIn( $section ) {
        $key = 'section.' . ltrim( $section, '.' );
        return $this->sprofiler->scopedProfileIn( $key );
    }

    /**
     * No-op for xhprof profiling.
     */
    public function close() {
    }

    /**
     * Check if a function or section should be excluded from the output.
     *
     * @param string $name Function or section name.
     * @return bool
     */
    private function shouldExclude( $name ) {
        if ( $name === '-total' ) {
            return true;
        }
        if ( !empty( $this->params['include'] ) ) {
            foreach ( $this->params['include'] as $pattern ) {
                if ( fnmatch( $pattern, $name, FNM_NOESCAPE ) ) {
                    return false;
                }
            }
            return true;
        }
        if ( !empty( $this->params['exclude'] ) ) {
            foreach ( $this->params['exclude'] as $pattern ) {
                if ( fnmatch( $pattern, $name, FNM_NOESCAPE ) ) {
                    return true;
                }
            }
        }
        return false;
    }

    public function getFunctionStats() {
        $metrics = $this->getXhprofData()->getCompleteMetrics();
        $profile = [];

        $main = null; // units in ms
        foreach ( $metrics as $fname => $stats ) {
            if ( $this->shouldExclude( $fname ) ) {
                continue;
            }
            // Convert elapsed times from μs to ms to match interface
            $entry = [
                'name' => $fname,
                'calls' => $stats['ct'],
                'real' => $stats['wt']['total'] / 1000,
                '%real' => $stats['wt']['percent'],
                'cpu' => ( $stats['cpu']['total'] ?? 0 ) / 1000,
                '%cpu' => $stats['cpu']['percent'] ?? 0,
                'memory' => $stats['mu']['total'] ?? 0,
                '%memory' => $stats['mu']['percent'] ?? 0,
                'min_real' => $stats['wt']['min'] / 1000,
                'max_real' => $stats['wt']['max'] / 1000
            ];
            $profile[] = $entry;
            if ( $fname === 'main()' ) {
                $main = $entry;
            }
        }

        // Merge in all of the custom profile sections
        foreach ( $this->sprofiler->getFunctionStats() as $stats ) {
            if ( $this->shouldExclude( $stats['name'] ) ) {
                continue;
            }

            // @note: getFunctionStats() values already in ms
            $stats['%real'] = $main['real'] ? $stats['real'] / $main['real'] * 100 : 0;
            $stats['%cpu'] = $main['cpu'] ? $stats['cpu'] / $main['cpu'] * 100 : 0;
            $stats['%memory'] = $main['memory'] ? $stats['memory'] / $main['memory'] * 100 : 0;
            $profile[] = $stats; // assume no section names collide with $metrics
        }

        return $profile;
    }

    /**
     * Returns a profiling output to be stored in debug file
     *
     * @return string
     */
    public function getOutput() {
        return $this->getFunctionReport();
    }

    /**
     * Get a report of profiled functions sorted by inclusive wall clock time
     * in descending order.
     *
     * Each line of the report includes this data:
     * - Function name
     * - Number of times function was called
     * - Total wall clock time spent in function in microseconds
     * - Minimum wall clock time spent in function in microseconds
     * - Average wall clock time spent in function in microseconds
     * - Maximum wall clock time spent in function in microseconds
     * - Percentage of total wall clock time spent in function
     * - Total delta of memory usage from start to end of function in bytes
     *
     * @return string
     */
    protected function getFunctionReport() {
        $data = $this->getFunctionStats();
        usort( $data, static function ( $a, $b ) {
            return $b['real'] <=> $a['real']; // descending
        } );

        $width = 140;
        $nameWidth = $width - 65;
        $format = "%-{$nameWidth}s %6d %9d %9d %9d %9d %7.3f%% %9d";
        $out = [];
        $out[] = sprintf( "%-{$nameWidth}s %6s %9s %9s %9s %9s %7s %9s",
            'Name', 'Calls', 'Total', 'Min', 'Each', 'Max', '%', 'Mem'
        );
        foreach ( $data as $stats ) {
            $out[] = sprintf( $format,
                $stats['name'],
                $stats['calls'],
                $stats['real'] * 1000,
                $stats['min_real'] * 1000,
                $stats['real'] / $stats['calls'] * 1000,
                $stats['max_real'] * 1000,
                $stats['%real'],
                $stats['memory']
            );
        }
        return implode( "\n", $out );
    }

    /**
     * Retrieve raw data from xhprof
     * @return array
     */
    public function getRawData() {
        return $this->getXhprofData()->getRawData();
    }
}