includes/profiler/SectionProfiler.php

   1 <?php
   2 /**
   3  * Arbitrary section name based PHP profiling.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Profiler
  22  */
  23 use Wikimedia\ScopedCallback;
  24
  25 /**
  26  * Custom PHP profiler for parser/DB type section names that xhprof/xdebug can't handle
  27  *
  28  * @since 1.25
  29  */
  30 class SectionProfiler {
  31         /** @var array Map of (mem,real,cpu) */
  32         protected $start;
  33         /** @var array Map of (mem,real,cpu) */
  34         protected $end;
  35         /** @var array List of resolved profile calls with start/end data */
  36         protected $stack = [];
  37         /** @var array Queue of open profile calls with start data */
  38         protected $workStack = [];
  39
  40         /** @var array Map of (function name => aggregate data array) */
  41         protected $collated = [];
  42         /** @var bool */
  43         protected $collateDone = false;
  44
  45         /** @var bool Whether to collect the full stack trace or just aggregates */
  46         protected $collateOnly = true;
  47         /** @var array Cache of a standard broken collation entry */
  48         protected $errorEntry;
  49
  50         /**
  51          * @param array $params
  52          */
  53         public function __construct( array $params = [] ) {
  54                 $this->errorEntry = $this->getErrorEntry();
  55                 $this->collateOnly = empty( $params['trace'] );
  56         }
  57
  58         /**
  59          * @param string $section
  60          * @return SectionProfileCallback
  61          */
  62         public function scopedProfileIn( $section ) {
  63                 $this->profileInInternal( $section );
  64
  65                 return new SectionProfileCallback( $this, $section );
  66         }
  67
  68         /**
  69          * @param ScopedCallback $section
  70          */
  71         public function scopedProfileOut( ScopedCallback &$section ) {
  72                 $section = null;
  73         }
  74
  75         /**
  76          * Get the aggregated inclusive profiling data for each method
  77          *
  78          * The percent time for each time is based on the current "total" time
  79          * used is based on all methods so far. This method can therefore be
  80          * called several times in between several profiling calls without the
  81          * delays in usage of the profiler skewing the results. A "-total" entry
  82          * is always included in the results.
  83          *
  84          * @return array List of method entries arrays, each having:
  85          *   - name    : method name
  86          *   - calls   : the number of invoking calls
  87          *   - real    : real time elapsed (ms)
  88          *   - %real   : percent real time
  89          *   - cpu     : real time elapsed (ms)
  90          *   - %cpu    : percent real time
  91          *   - memory  : memory used (bytes)
  92          *   - %memory : percent memory used
  93          *   - min_real : min real time in a call (ms)
  94          *   - max_real : max real time in a call (ms)
  95          */
  96         public function getFunctionStats() {
  97                 $this->collateData();
  98
  99                 $totalCpu = max( $this->end['cpu'] - $this->start['cpu'], 0 );
 100                 $totalReal = max( $this->end['real'] - $this->start['real'], 0 );
 101                 $totalMem = max( $this->end['memory'] - $this->start['memory'], 0 );
 102
 103                 $profile = [];
 104                 foreach ( $this->collated as $fname => $data ) {
 105                         $profile[] = [
 106                                 'name' => $fname,
 107                                 'calls' => $data['count'],
 108                                 'real' => $data['real'] * 1000,
 109                                 '%real' => $totalReal ? 100 * $data['real'] / $totalReal : 0,
 110                                 'cpu' => $data['cpu'] * 1000,
 111                                 '%cpu' => $totalCpu ? 100 * $data['cpu'] / $totalCpu : 0,
 112                                 'memory' => $data['memory'],
 113                                 '%memory' => $totalMem ? 100 * $data['memory'] / $totalMem : 0,
 114                                 'min_real' => 1000 * $data['min_real'],
 115                                 'max_real' => 1000 * $data['max_real']
 116                         ];
 117                 }
 118
 119                 $profile[] = [
 120                         'name' => '-total',
 121                         'calls' => 1,
 122                         'real' => 1000 * $totalReal,
 123                         '%real' => 100,
 124                         'cpu' => 1000 * $totalCpu,
 125                         '%cpu' => 100,
 126                         'memory' => $totalMem,
 127                         '%memory' => 100,
 128                         'min_real' => 1000 * $totalReal,
 129                         'max_real' => 1000 * $totalReal
 130                 ];
 131
 132                 return $profile;
 133         }
 134
 135         /**
 136          * Clear all of the profiling data for another run
 137          */
 138         public function reset() {
 139                 $this->start = null;
 140                 $this->end = null;
 141                 $this->stack = [];
 142                 $this->workStack = [];
 143                 $this->collated = [];
 144                 $this->collateDone = false;
 145         }
 146
 147         /**
 148          * @return array Initial collation entry
 149          */
 150         protected function getZeroEntry() {
 151                 return [
 152                         'cpu'      => 0.0,
 153                         'real'     => 0.0,
 154                         'memory'   => 0,
 155                         'count'    => 0,
 156                         'min_real' => 0.0,
 157                         'max_real' => 0.0
 158                 ];
 159         }
 160
 161         /**
 162          * @return array Initial collation entry for errors
 163          */
 164         protected function getErrorEntry() {
 165                 $entry = $this->getZeroEntry();
 166                 $entry['count'] = 1;
 167                 return $entry;
 168         }
 169
 170         /**
 171          * Update the collation entry for a given method name
 172          *
 173          * @param string $name
 174          * @param float $elapsedCpu
 175          * @param float $elapsedReal
 176          * @param int $memChange
 177          */
 178         protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) {
 179                 $entry =& $this->collated[$name];
 180                 if ( !is_array( $entry ) ) {
 181                         $entry = $this->getZeroEntry();
 182                         $this->collated[$name] =& $entry;
 183                 }
 184                 $entry['cpu'] += $elapsedCpu;
 185                 $entry['real'] += $elapsedReal;
 186                 $entry['memory'] += $memChange > 0 ? $memChange : 0;
 187                 $entry['count']++;
 188                 $entry['min_real'] = min( $entry['min_real'], $elapsedReal );
 189                 $entry['max_real'] = max( $entry['max_real'], $elapsedReal );
 190         }
 191
 192         /**
 193          * This method should not be called outside SectionProfiler
 194          *
 195          * @param string $functionname
 196          */
 197         public function profileInInternal( $functionname ) {
 198                 // Once the data is collated for reports, any future calls
 199                 // should clear the collation cache so the next report will
 200                 // reflect them. This matters when trace mode is used.
 201                 $this->collateDone = false;
 202
 203                 $cpu = $this->getTime( 'cpu' );
 204                 $real = $this->getTime( 'wall' );
 205                 $memory = memory_get_usage();
 206
 207                 if ( $this->start === null ) {
 208                         $this->start = [ 'cpu' => $cpu, 'real' => $real, 'memory' => $memory ];
 209                 }
 210
 211                 $this->workStack[] = [
 212                         $functionname,
 213                         count( $this->workStack ),
 214                         $real,
 215                         $cpu,
 216                         $memory
 217                 ];
 218         }
 219
 220         /**
 221          * This method should not be called outside SectionProfiler
 222          *
 223          * @param string $functionname
 224          */
 225         public function profileOutInternal( $functionname ) {
 226                 $item = array_pop( $this->workStack );
 227                 if ( $item === null ) {
 228                         $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
 229                         return;
 230                 }
 231                 list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;
 232
 233                 if ( $functionname === 'close' ) {
 234                         $message = "Profile section ended by close(): {$ofname}";
 235                         $this->debugGroup( 'profileerror', $message );
 236                         if ( $this->collateOnly ) {
 237                                 $this->collated[$message] = $this->errorEntry;
 238                         } else {
 239                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 240                         }
 241                         $functionname = $ofname;
 242                 } elseif ( $ofname !== $functionname ) {
 243                         $message = "Profiling error: in({$ofname}), out($functionname)";
 244                         $this->debugGroup( 'profileerror', $message );
 245                         if ( $this->collateOnly ) {
 246                                 $this->collated[$message] = $this->errorEntry;
 247                         } else {
 248                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 249                         }
 250                 }
 251
 252                 $realTime = $this->getTime( 'wall' );
 253                 $cpuTime = $this->getTime( 'cpu' );
 254                 $memUsage = memory_get_usage();
 255
 256                 if ( $this->collateOnly ) {
 257                         $elapsedcpu = $cpuTime - $octime;
 258                         $elapsedreal = $realTime - $ortime;
 259                         $memchange = $memUsage - $omem;
 260                         $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
 261                 } else {
 262                         $this->stack[] = array_merge( $item, [ $realTime, $cpuTime, $memUsage ] );
 263                 }
 264
 265                 $this->end = [
 266                         'cpu'      => $cpuTime,
 267                         'real'     => $realTime,
 268                         'memory'   => $memUsage
 269                 ];
 270         }
 271
 272         /**
 273          * Returns a tree of function calls with their real times
 274          * @return string
 275          * @throws Exception
 276          */
 277         public function getCallTreeReport() {
 278                 if ( $this->collateOnly ) {
 279                         throw new Exception( "Tree is only available for trace profiling." );
 280                 }
 281                 return implode( '', array_map(
 282                         [ $this, 'getCallTreeLine' ], $this->remapCallTree( $this->stack )
 283                 ) );
 284         }
 285
 286         /**
 287          * Recursive function the format the current profiling array into a tree
 288          *
 289          * @param array $stack Profiling array
 290          * @return array
 291          */
 292         protected function remapCallTree( array $stack ) {
 293                 if ( count( $stack ) < 2 ) {
 294                         return $stack;
 295                 }
 296                 $outputs = [];
 297                 for ( $max = count( $stack ) - 1; $max > 0; ) {
 298                         /* Find all items under this entry */
 299                         $level = $stack[$max][1];
 300                         $working = [];
 301                         for ( $i = $max -1; $i >= 0; $i-- ) {
 302                                 if ( $stack[$i][1] > $level ) {
 303                                         $working[] = $stack[$i];
 304                                 } else {
 305                                         break;
 306                                 }
 307                         }
 308                         $working = $this->remapCallTree( array_reverse( $working ) );
 309                         $output = [];
 310                         foreach ( $working as $item ) {
 311                                 array_push( $output, $item );
 312                         }
 313                         array_unshift( $output, $stack[$max] );
 314                         $max = $i;
 315
 316                         array_unshift( $outputs, $output );
 317                 }
 318                 $final = [];
 319                 foreach ( $outputs as $output ) {
 320                         foreach ( $output as $item ) {
 321                                 $final[] = $item;
 322                         }
 323                 }
 324                 return $final;
 325         }
 326
 327         /**
 328          * Callback to get a formatted line for the call tree
 329          * @param array $entry
 330          * @return string
 331          */
 332         protected function getCallTreeLine( $entry ) {
 333                 // $entry has (name, level, stime, scpu, smem, etime, ecpu, emem)
 334                 list( $fname, $level, $startreal, , , $endreal ) = $entry;
 335                 $delta = $endreal - $startreal;
 336                 $space = str_repeat( ' ', $level );
 337                 # The ugly double sprintf is to work around a PHP bug,
 338                 # which has been fixed in recent releases.
 339                 return sprintf( "%10s %s %s\n",
 340                         trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
 341         }
 342
 343         /**
 344          * Populate collated data
 345          */
 346         protected function collateData() {
 347                 if ( $this->collateDone ) {
 348                         return;
 349                 }
 350                 $this->collateDone = true;
 351                 // Close opened profiling sections
 352                 while ( count( $this->workStack ) ) {
 353                         $this->profileOutInternal( 'close' );
 354                 }
 355
 356                 if ( $this->collateOnly ) {
 357                         return; // already collated as methods exited
 358                 }
 359
 360                 $this->collated = [];
 361
 362                 # Estimate profiling overhead
 363                 $oldEnd = $this->end;
 364                 $profileCount = count( $this->stack );
 365                 $this->calculateOverhead( $profileCount );
 366
 367                 # First, subtract the overhead!
 368                 $overheadTotal = $overheadMemory = $overheadInternal = [];
 369                 foreach ( $this->stack as $entry ) {
 370                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 371                         $fname = $entry[0];
 372                         $elapsed = $entry[5] - $entry[2];
 373                         $memchange = $entry[7] - $entry[4];
 374
 375                         if ( $fname === '-overhead-total' ) {
 376                                 $overheadTotal[] = $elapsed;
 377                                 $overheadMemory[] = max( 0, $memchange );
 378                         } elseif ( $fname === '-overhead-internal' ) {
 379                                 $overheadInternal[] = $elapsed;
 380                         }
 381                 }
 382                 $overheadTotal = $overheadTotal ?
 383                         array_sum( $overheadTotal ) / count( $overheadInternal ) : 0;
 384                 $overheadMemory = $overheadMemory ?
 385                         array_sum( $overheadMemory ) / count( $overheadInternal ) : 0;
 386                 $overheadInternal = $overheadInternal ?
 387                         array_sum( $overheadInternal ) / count( $overheadInternal ) : 0;
 388
 389                 # Collate
 390                 foreach ( $this->stack as $index => $entry ) {
 391                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 392                         $fname = $entry[0];
 393                         $elapsedCpu = $entry[6] - $entry[3];
 394                         $elapsedReal = $entry[5] - $entry[2];
 395                         $memchange = $entry[7] - $entry[4];
 396                         $subcalls = $this->calltreeCount( $this->stack, $index );
 397
 398                         if ( substr( $fname, 0, 9 ) !== '-overhead' ) {
 399                                 # Adjust for profiling overhead (except special values with elapsed=0)
 400                                 if ( $elapsed ) {
 401                                         $elapsed -= $overheadInternal;
 402                                         $elapsed -= ( $subcalls * $overheadTotal );
 403                                         $memchange -= ( $subcalls * $overheadMemory );
 404                                 }
 405                         }
 406
 407                         $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange );
 408                 }
 409
 410                 $this->collated['-overhead-total']['count'] = $profileCount;
 411                 arsort( $this->collated, SORT_NUMERIC );
 412
 413                 // Unclobber the end info map (the overhead checking alters it)
 414                 $this->end = $oldEnd;
 415         }
 416
 417         /**
 418          * Dummy calls to calculate profiling overhead
 419          *
 420          * @param int $profileCount
 421          */
 422         protected function calculateOverhead( $profileCount ) {
 423                 $this->profileInInternal( '-overhead-total' );
 424                 for ( $i = 0; $i < $profileCount; $i++ ) {
 425                         $this->profileInInternal( '-overhead-internal' );
 426                         $this->profileOutInternal( '-overhead-internal' );
 427                 }
 428                 $this->profileOutInternal( '-overhead-total' );
 429         }
 430
 431         /**
 432          * Counts the number of profiled function calls sitting under
 433          * the given point in the call graph. Not the most efficient algo.
 434          *
 435          * @param array $stack
 436          * @param int $start
 437          * @return int
 438          */
 439         protected function calltreeCount( $stack, $start ) {
 440                 $level = $stack[$start][1];
 441                 $count = 0;
 442                 for ( $i = $start -1; $i >= 0 && $stack[$i][1] > $level; $i-- ) {
 443                         $count ++;
 444                 }
 445                 return $count;
 446         }
 447
 448         /**
 449          * Get the initial time of the request, based on getrusage()
 450          *
 451          * @param string|bool $metric Metric to use, with the following possibilities:
 452          *   - user: User CPU time (without system calls)
 453          *   - cpu: Total CPU time (user and system calls)
 454          *   - wall (or any other string): elapsed time
 455          *   - false (default): will fall back to default metric
 456          * @return float
 457          */
 458         protected function getTime( $metric = 'wall' ) {
 459                 if ( $metric === 'cpu' || $metric === 'user' ) {
 460                         $ru = wfGetRusage();
 461                         if ( !$ru ) {
 462                                 return 0;
 463                         }
 464                         $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
 465                         if ( $metric === 'cpu' ) {
 466                                 # This is the time of system calls, added to the user time
 467                                 # it gives the total CPU time
 468                                 $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
 469                         }
 470                         return $time;
 471                 } else {
 472                         return microtime( true );
 473                 }
 474         }
 475
 476         /**
 477          * Add an entry in the debug log file
 478          *
 479          * @param string $s String to output
 480          */
 481         protected function debug( $s ) {
 482                 if ( function_exists( 'wfDebug' ) ) {
 483                         wfDebug( $s );
 484                 }
 485         }
 486
 487         /**
 488          * Add an entry in the debug log group
 489          *
 490          * @param string $group Group to send the message to
 491          * @param string $s String to output
 492          */
 493         protected function debugGroup( $group, $s ) {
 494                 if ( function_exists( 'wfDebugLog' ) ) {
 495                         wfDebugLog( $group, $s );
 496                 }
 497         }
 498 }
 499
 500 /**
 501  * Subclass ScopedCallback to avoid call_user_func_array(), which is slow
 502  *
 503  * This class should not be used outside of SectionProfiler
 504  */
 505 class SectionProfileCallback extends ScopedCallback {
 506         /** @var SectionProfiler */
 507         protected $profiler;
 508         /** @var string */
 509         protected $section;
 510
 511         /**
 512          * @param SectionProfiler $profiler
 513          * @param string $section
 514          */
 515         public function __construct( SectionProfiler $profiler, $section ) {
 516                 parent::__construct( null );
 517                 $this->profiler = $profiler;
 518                 $this->section = $section;
 519         }
 520
 521         function __destruct() {
 522                 $this->profiler->profileOutInternal( $this->section );
 523         }
 524 }