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                 if ( is_array( $this->start ) ) {
 100                         $totalCpu = max( $this->end['cpu'] - $this->start['cpu'], 0 );
 101                         $totalReal = max( $this->end['real'] - $this->start['real'], 0 );
 102                         $totalMem = max( $this->end['memory'] - $this->start['memory'], 0 );
 103                 } else {
 104                         $totalCpu = 0;
 105                         $totalReal = 0;
 106                         $totalMem = 0;
 107                 }
 108
 109                 $profile = [];
 110                 foreach ( $this->collated as $fname => $data ) {
 111                         $profile[] = [
 112                                 'name' => $fname,
 113                                 'calls' => $data['count'],
 114                                 'real' => $data['real'] * 1000,
 115                                 '%real' => $totalReal ? 100 * $data['real'] / $totalReal : 0,
 116                                 'cpu' => $data['cpu'] * 1000,
 117                                 '%cpu' => $totalCpu ? 100 * $data['cpu'] / $totalCpu : 0,
 118                                 'memory' => $data['memory'],
 119                                 '%memory' => $totalMem ? 100 * $data['memory'] / $totalMem : 0,
 120                                 'min_real' => 1000 * $data['min_real'],
 121                                 'max_real' => 1000 * $data['max_real']
 122                         ];
 123                 }
 124
 125                 $profile[] = [
 126                         'name' => '-total',
 127                         'calls' => 1,
 128                         'real' => 1000 * $totalReal,
 129                         '%real' => 100,
 130                         'cpu' => 1000 * $totalCpu,
 131                         '%cpu' => 100,
 132                         'memory' => $totalMem,
 133                         '%memory' => 100,
 134                         'min_real' => 1000 * $totalReal,
 135                         'max_real' => 1000 * $totalReal
 136                 ];
 137
 138                 return $profile;
 139         }
 140
 141         /**
 142          * Clear all of the profiling data for another run
 143          */
 144         public function reset() {
 145                 $this->start = null;
 146                 $this->end = null;
 147                 $this->stack = [];
 148                 $this->workStack = [];
 149                 $this->collated = [];
 150                 $this->collateDone = false;
 151         }
 152
 153         /**
 154          * @return array Initial collation entry
 155          */
 156         protected function getZeroEntry() {
 157                 return [
 158                         'cpu'      => 0.0,
 159                         'real'     => 0.0,
 160                         'memory'   => 0,
 161                         'count'    => 0,
 162                         'min_real' => 0.0,
 163                         'max_real' => 0.0
 164                 ];
 165         }
 166
 167         /**
 168          * @return array Initial collation entry for errors
 169          */
 170         protected function getErrorEntry() {
 171                 $entry = $this->getZeroEntry();
 172                 $entry['count'] = 1;
 173                 return $entry;
 174         }
 175
 176         /**
 177          * Update the collation entry for a given method name
 178          *
 179          * @param string $name
 180          * @param float $elapsedCpu
 181          * @param float $elapsedReal
 182          * @param int $memChange
 183          */
 184         protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) {
 185                 $entry =& $this->collated[$name];
 186                 if ( !is_array( $entry ) ) {
 187                         $entry = $this->getZeroEntry();
 188                         $this->collated[$name] =& $entry;
 189                 }
 190                 $entry['cpu'] += $elapsedCpu;
 191                 $entry['real'] += $elapsedReal;
 192                 $entry['memory'] += $memChange > 0 ? $memChange : 0;
 193                 $entry['count']++;
 194                 $entry['min_real'] = min( $entry['min_real'], $elapsedReal );
 195                 $entry['max_real'] = max( $entry['max_real'], $elapsedReal );
 196         }
 197
 198         /**
 199          * This method should not be called outside SectionProfiler
 200          *
 201          * @param string $functionname
 202          */
 203         public function profileInInternal( $functionname ) {
 204                 // Once the data is collated for reports, any future calls
 205                 // should clear the collation cache so the next report will
 206                 // reflect them. This matters when trace mode is used.
 207                 $this->collateDone = false;
 208
 209                 $cpu = $this->getTime( 'cpu' );
 210                 $real = $this->getTime( 'wall' );
 211                 $memory = memory_get_usage();
 212
 213                 if ( $this->start === null ) {
 214                         $this->start = [ 'cpu' => $cpu, 'real' => $real, 'memory' => $memory ];
 215                 }
 216
 217                 $this->workStack[] = [
 218                         $functionname,
 219                         count( $this->workStack ),
 220                         $real,
 221                         $cpu,
 222                         $memory
 223                 ];
 224         }
 225
 226         /**
 227          * This method should not be called outside SectionProfiler
 228          *
 229          * @param string $functionname
 230          */
 231         public function profileOutInternal( $functionname ) {
 232                 $item = array_pop( $this->workStack );
 233                 if ( $item === null ) {
 234                         $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
 235                         return;
 236                 }
 237                 list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;
 238
 239                 if ( $functionname === 'close' ) {
 240                         $message = "Profile section ended by close(): {$ofname}";
 241                         $this->debugGroup( 'profileerror', $message );
 242                         if ( $this->collateOnly ) {
 243                                 $this->collated[$message] = $this->errorEntry;
 244                         } else {
 245                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 246                         }
 247                         $functionname = $ofname;
 248                 } elseif ( $ofname !== $functionname ) {
 249                         $message = "Profiling error: in({$ofname}), out($functionname)";
 250                         $this->debugGroup( 'profileerror', $message );
 251                         if ( $this->collateOnly ) {
 252                                 $this->collated[$message] = $this->errorEntry;
 253                         } else {
 254                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 255                         }
 256                 }
 257
 258                 $realTime = $this->getTime( 'wall' );
 259                 $cpuTime = $this->getTime( 'cpu' );
 260                 $memUsage = memory_get_usage();
 261
 262                 if ( $this->collateOnly ) {
 263                         $elapsedcpu = $cpuTime - $octime;
 264                         $elapsedreal = $realTime - $ortime;
 265                         $memchange = $memUsage - $omem;
 266                         $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
 267                 } else {
 268                         $this->stack[] = array_merge( $item, [ $realTime, $cpuTime, $memUsage ] );
 269                 }
 270
 271                 $this->end = [
 272                         'cpu'      => $cpuTime,
 273                         'real'     => $realTime,
 274                         'memory'   => $memUsage
 275                 ];
 276         }
 277
 278         /**
 279          * Returns a tree of function calls with their real times
 280          * @return string
 281          * @throws Exception
 282          */
 283         public function getCallTreeReport() {
 284                 if ( $this->collateOnly ) {
 285                         throw new Exception( "Tree is only available for trace profiling." );
 286                 }
 287                 return implode( '', array_map(
 288                         [ $this, 'getCallTreeLine' ], $this->remapCallTree( $this->stack )
 289                 ) );
 290         }
 291
 292         /**
 293          * Recursive function the format the current profiling array into a tree
 294          *
 295          * @param array $stack Profiling array
 296          * @return array
 297          */
 298         protected function remapCallTree( array $stack ) {
 299                 if ( count( $stack ) < 2 ) {
 300                         return $stack;
 301                 }
 302                 $outputs = [];
 303                 for ( $max = count( $stack ) - 1; $max > 0; ) {
 304                         /* Find all items under this entry */
 305                         $level = $stack[$max][1];
 306                         $working = [];
 307                         for ( $i = $max - 1; $i >= 0; $i-- ) {
 308                                 if ( $stack[$i][1] > $level ) {
 309                                         $working[] = $stack[$i];
 310                                 } else {
 311                                         break;
 312                                 }
 313                         }
 314                         $working = $this->remapCallTree( array_reverse( $working ) );
 315                         $output = [];
 316                         foreach ( $working as $item ) {
 317                                 array_push( $output, $item );
 318                         }
 319                         array_unshift( $output, $stack[$max] );
 320                         $max = $i;
 321
 322                         array_unshift( $outputs, $output );
 323                 }
 324                 $final = [];
 325                 foreach ( $outputs as $output ) {
 326                         foreach ( $output as $item ) {
 327                                 $final[] = $item;
 328                         }
 329                 }
 330                 return $final;
 331         }
 332
 333         /**
 334          * Callback to get a formatted line for the call tree
 335          * @param array $entry
 336          * @return string
 337          */
 338         protected function getCallTreeLine( $entry ) {
 339                 // $entry has (name, level, stime, scpu, smem, etime, ecpu, emem)
 340                 list( $fname, $level, $startreal, , , $endreal ) = $entry;
 341                 $delta = $endreal - $startreal;
 342                 $space = str_repeat( ' ', $level );
 343                 # The ugly double sprintf is to work around a PHP bug,
 344                 # which has been fixed in recent releases.
 345                 return sprintf( "%10s %s %s\n",
 346                         trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
 347         }
 348
 349         /**
 350          * Populate collated data
 351          */
 352         protected function collateData() {
 353                 if ( $this->collateDone ) {
 354                         return;
 355                 }
 356                 $this->collateDone = true;
 357                 // Close opened profiling sections
 358                 while ( count( $this->workStack ) ) {
 359                         $this->profileOutInternal( 'close' );
 360                 }
 361
 362                 if ( $this->collateOnly ) {
 363                         return; // already collated as methods exited
 364                 }
 365
 366                 $this->collated = [];
 367
 368                 # Estimate profiling overhead
 369                 $oldEnd = $this->end;
 370                 $profileCount = count( $this->stack );
 371                 $this->calculateOverhead( $profileCount );
 372
 373                 # First, subtract the overhead!
 374                 $overheadTotal = $overheadMemory = $overheadInternal = [];
 375                 foreach ( $this->stack as $entry ) {
 376                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 377                         $fname = $entry[0];
 378                         $elapsed = $entry[5] - $entry[2];
 379                         $memchange = $entry[7] - $entry[4];
 380
 381                         if ( $fname === '-overhead-total' ) {
 382                                 $overheadTotal[] = $elapsed;
 383                                 $overheadMemory[] = max( 0, $memchange );
 384                         } elseif ( $fname === '-overhead-internal' ) {
 385                                 $overheadInternal[] = $elapsed;
 386                         }
 387                 }
 388                 $overheadTotal = $overheadTotal ?
 389                         array_sum( $overheadTotal ) / count( $overheadInternal ) : 0;
 390                 $overheadMemory = $overheadMemory ?
 391                         array_sum( $overheadMemory ) / count( $overheadInternal ) : 0;
 392                 $overheadInternal = $overheadInternal ?
 393                         array_sum( $overheadInternal ) / count( $overheadInternal ) : 0;
 394
 395                 # Collate
 396                 foreach ( $this->stack as $index => $entry ) {
 397                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 398                         $fname = $entry[0];
 399                         $elapsedCpu = $entry[6] - $entry[3];
 400                         $elapsedReal = $entry[5] - $entry[2];
 401                         $memchange = $entry[7] - $entry[4];
 402                         $subcalls = $this->calltreeCount( $this->stack, $index );
 403
 404                         if ( substr( $fname, 0, 9 ) !== '-overhead' ) {
 405                                 # Adjust for profiling overhead (except special values with elapsed=0)
 406                                 if ( $elapsed ) {
 407                                         $elapsed -= $overheadInternal;
 408                                         $elapsed -= ( $subcalls * $overheadTotal );
 409                                         $memchange -= ( $subcalls * $overheadMemory );
 410                                 }
 411                         }
 412
 413                         $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange );
 414                 }
 415
 416                 $this->collated['-overhead-total']['count'] = $profileCount;
 417                 arsort( $this->collated, SORT_NUMERIC );
 418
 419                 // Unclobber the end info map (the overhead checking alters it)
 420                 $this->end = $oldEnd;
 421         }
 422
 423         /**
 424          * Dummy calls to calculate profiling overhead
 425          *
 426          * @param int $profileCount
 427          */
 428         protected function calculateOverhead( $profileCount ) {
 429                 $this->profileInInternal( '-overhead-total' );
 430                 for ( $i = 0; $i < $profileCount; $i++ ) {
 431                         $this->profileInInternal( '-overhead-internal' );
 432                         $this->profileOutInternal( '-overhead-internal' );
 433                 }
 434                 $this->profileOutInternal( '-overhead-total' );
 435         }
 436
 437         /**
 438          * Counts the number of profiled function calls sitting under
 439          * the given point in the call graph. Not the most efficient algo.
 440          *
 441          * @param array $stack
 442          * @param int $start
 443          * @return int
 444          */
 445         protected function calltreeCount( $stack, $start ) {
 446                 $level = $stack[$start][1];
 447                 $count = 0;
 448                 for ( $i = $start - 1; $i >= 0 && $stack[$i][1] > $level; $i-- ) {
 449                         $count++;
 450                 }
 451                 return $count;
 452         }
 453
 454         /**
 455          * Get the initial time of the request, based on getrusage()
 456          *
 457          * @param string|bool $metric Metric to use, with the following possibilities:
 458          *   - user: User CPU time (without system calls)
 459          *   - cpu: Total CPU time (user and system calls)
 460          *   - wall (or any other string): elapsed time
 461          *   - false (default): will fall back to default metric
 462          * @return float
 463          */
 464         protected function getTime( $metric = 'wall' ) {
 465                 if ( $metric === 'cpu' || $metric === 'user' ) {
 466                         $ru = wfGetRusage();
 467                         if ( !$ru ) {
 468                                 return 0;
 469                         }
 470                         $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
 471                         if ( $metric === 'cpu' ) {
 472                                 # This is the time of system calls, added to the user time
 473                                 # it gives the total CPU time
 474                                 $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
 475                         }
 476                         return $time;
 477                 } else {
 478                         return microtime( true );
 479                 }
 480         }
 481
 482         /**
 483          * Add an entry in the debug log file
 484          *
 485          * @param string $s String to output
 486          */
 487         protected function debug( $s ) {
 488                 if ( function_exists( 'wfDebug' ) ) {
 489                         wfDebug( $s );
 490                 }
 491         }
 492
 493         /**
 494          * Add an entry in the debug log group
 495          *
 496          * @param string $group Group to send the message to
 497          * @param string $s String to output
 498          */
 499         protected function debugGroup( $group, $s ) {
 500                 if ( function_exists( 'wfDebugLog' ) ) {
 501                         wfDebugLog( $group, $s );
 502                 }
 503         }
 504 }