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  * @author Aaron Schulz
  23  */
  24 use Wikimedia\ScopedCallback;
  25
  26 /**
  27  * Custom PHP profiler for parser/DB type section names that xhprof/xdebug can't handle
  28  *
  29  * @since 1.25
  30  */
  31 class SectionProfiler {
  32         /** @var array Map of (mem,real,cpu) */
  33         protected $start;
  34         /** @var array Map of (mem,real,cpu) */
  35         protected $end;
  36         /** @var array List of resolved profile calls with start/end data */
  37         protected $stack = [];
  38         /** @var array Queue of open profile calls with start data */
  39         protected $workStack = [];
  40
  41         /** @var array Map of (function name => aggregate data array) */
  42         protected $collated = [];
  43         /** @var bool */
  44         protected $collateDone = false;
  45
  46         /** @var bool Whether to collect the full stack trace or just aggregates */
  47         protected $collateOnly = true;
  48         /** @var array Cache of a standard broken collation entry */
  49         protected $errorEntry;
  50
  51         /**
  52          * @param array $params
  53          */
  54         public function __construct( array $params = [] ) {
  55                 $this->errorEntry = $this->getErrorEntry();
  56                 $this->collateOnly = empty( $params['trace'] );
  57         }
  58
  59         /**
  60          * @param string $section
  61          * @return SectionProfileCallback
  62          */
  63         public function scopedProfileIn( $section ) {
  64                 $this->profileInInternal( $section );
  65
  66                 return new SectionProfileCallback( $this, $section );
  67         }
  68
  69         /**
  70          * @param ScopedCallback $section
  71          */
  72         public function scopedProfileOut( ScopedCallback &$section ) {
  73                 $section = null;
  74         }
  75
  76         /**
  77          * Get the aggregated inclusive profiling data for each method
  78          *
  79          * The percent time for each time is based on the current "total" time
  80          * used is based on all methods so far. This method can therefore be
  81          * called several times in between several profiling calls without the
  82          * delays in usage of the profiler skewing the results. A "-total" entry
  83          * is always included in the results.
  84          *
  85          * @return array List of method entries arrays, each having:
  86          *   - name    : method name
  87          *   - calls   : the number of invoking calls
  88          *   - real    : real time elapsed (ms)
  89          *   - %real   : percent real time
  90          *   - cpu     : real time elapsed (ms)
  91          *   - %cpu    : percent real time
  92          *   - memory  : memory used (bytes)
  93          *   - %memory : percent memory used
  94          *   - min_real : min real time in a call (ms)
  95          *   - max_real : max real time in a call (ms)
  96          */
  97         public function getFunctionStats() {
  98                 $this->collateData();
  99
 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
 104                 $profile = [];
 105                 foreach ( $this->collated as $fname => $data ) {
 106                         $profile[] = [
 107                                 'name' => $fname,
 108                                 'calls' => $data['count'],
 109                                 'real' => $data['real'] * 1000,
 110                                 '%real' => $totalReal ? 100 * $data['real'] / $totalReal : 0,
 111                                 'cpu' => $data['cpu'] * 1000,
 112                                 '%cpu' => $totalCpu ? 100 * $data['cpu'] / $totalCpu : 0,
 113                                 'memory' => $data['memory'],
 114                                 '%memory' => $totalMem ? 100 * $data['memory'] / $totalMem : 0,
 115                                 'min_real' => 1000 * $data['min_real'],
 116                                 'max_real' => 1000 * $data['max_real']
 117                         ];
 118                 }
 119
 120                 $profile[] = [
 121                         'name' => '-total',
 122                         'calls' => 1,
 123                         'real' => 1000 * $totalReal,
 124                         '%real' => 100,
 125                         'cpu' => 1000 * $totalCpu,
 126                         '%cpu' => 100,
 127                         'memory' => $totalMem,
 128                         '%memory' => 100,
 129                         'min_real' => 1000 * $totalReal,
 130                         'max_real' => 1000 * $totalReal
 131                 ];
 132
 133                 return $profile;
 134         }
 135
 136         /**
 137          * Clear all of the profiling data for another run
 138          */
 139         public function reset() {
 140                 $this->start = null;
 141                 $this->end = null;
 142                 $this->stack = [];
 143                 $this->workStack = [];
 144                 $this->collated = [];
 145                 $this->collateDone = false;
 146         }
 147
 148         /**
 149          * @return array Initial collation entry
 150          */
 151         protected function getZeroEntry() {
 152                 return [
 153                         'cpu'      => 0.0,
 154                         'real'     => 0.0,
 155                         'memory'   => 0,
 156                         'count'    => 0,
 157                         'min_real' => 0.0,
 158                         'max_real' => 0.0
 159                 ];
 160         }
 161
 162         /**
 163          * @return array Initial collation entry for errors
 164          */
 165         protected function getErrorEntry() {
 166                 $entry = $this->getZeroEntry();
 167                 $entry['count'] = 1;
 168                 return $entry;
 169         }
 170
 171         /**
 172          * Update the collation entry for a given method name
 173          *
 174          * @param string $name
 175          * @param float $elapsedCpu
 176          * @param float $elapsedReal
 177          * @param int $memChange
 178          */
 179         protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) {
 180                 $entry =& $this->collated[$name];
 181                 if ( !is_array( $entry ) ) {
 182                         $entry = $this->getZeroEntry();
 183                         $this->collated[$name] =& $entry;
 184                 }
 185                 $entry['cpu'] += $elapsedCpu;
 186                 $entry['real'] += $elapsedReal;
 187                 $entry['memory'] += $memChange > 0 ? $memChange : 0;
 188                 $entry['count']++;
 189                 $entry['min_real'] = min( $entry['min_real'], $elapsedReal );
 190                 $entry['max_real'] = max( $entry['max_real'], $elapsedReal );
 191         }
 192
 193         /**
 194          * This method should not be called outside SectionProfiler
 195          *
 196          * @param string $functionname
 197          */
 198         public function profileInInternal( $functionname ) {
 199                 // Once the data is collated for reports, any future calls
 200                 // should clear the collation cache so the next report will
 201                 // reflect them. This matters when trace mode is used.
 202                 $this->collateDone = false;
 203
 204                 $cpu = $this->getTime( 'cpu' );
 205                 $real = $this->getTime( 'wall' );
 206                 $memory = memory_get_usage();
 207
 208                 if ( $this->start === null ) {
 209                         $this->start = [ 'cpu' => $cpu, 'real' => $real, 'memory' => $memory ];
 210                 }
 211
 212                 $this->workStack[] = [
 213                         $functionname,
 214                         count( $this->workStack ),
 215                         $real,
 216                         $cpu,
 217                         $memory
 218                 ];
 219         }
 220
 221         /**
 222          * This method should not be called outside SectionProfiler
 223          *
 224          * @param string $functionname
 225          */
 226         public function profileOutInternal( $functionname ) {
 227                 $item = array_pop( $this->workStack );
 228                 if ( $item === null ) {
 229                         $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
 230                         return;
 231                 }
 232                 list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;
 233
 234                 if ( $functionname === 'close' ) {
 235                         $message = "Profile section ended by close(): {$ofname}";
 236                         $this->debugGroup( 'profileerror', $message );
 237                         if ( $this->collateOnly ) {
 238                                 $this->collated[$message] = $this->errorEntry;
 239                         } else {
 240                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 241                         }
 242                         $functionname = $ofname;
 243                 } elseif ( $ofname !== $functionname ) {
 244                         $message = "Profiling error: in({$ofname}), out($functionname)";
 245                         $this->debugGroup( 'profileerror', $message );
 246                         if ( $this->collateOnly ) {
 247                                 $this->collated[$message] = $this->errorEntry;
 248                         } else {
 249                                 $this->stack[] = [ $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 ];
 250                         }
 251                 }
 252
 253                 $realTime = $this->getTime( 'wall' );
 254                 $cpuTime = $this->getTime( 'cpu' );
 255                 $memUsage = memory_get_usage();
 256
 257                 if ( $this->collateOnly ) {
 258                         $elapsedcpu = $cpuTime - $octime;
 259                         $elapsedreal = $realTime - $ortime;
 260                         $memchange = $memUsage - $omem;
 261                         $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
 262                 } else {
 263                         $this->stack[] = array_merge( $item, [ $realTime, $cpuTime, $memUsage ] );
 264                 }
 265
 266                 $this->end = [
 267                         'cpu'      => $cpuTime,
 268                         'real'     => $realTime,
 269                         'memory'   => $memUsage
 270                 ];
 271         }
 272
 273         /**
 274          * Returns a tree of function calls with their real times
 275          * @return string
 276          * @throws Exception
 277          */
 278         public function getCallTreeReport() {
 279                 if ( $this->collateOnly ) {
 280                         throw new Exception( "Tree is only available for trace profiling." );
 281                 }
 282                 return implode( '', array_map(
 283                         [ $this, 'getCallTreeLine' ], $this->remapCallTree( $this->stack )
 284                 ) );
 285         }
 286
 287         /**
 288          * Recursive function the format the current profiling array into a tree
 289          *
 290          * @param array $stack Profiling array
 291          * @return array
 292          */
 293         protected function remapCallTree( array $stack ) {
 294                 if ( count( $stack ) < 2 ) {
 295                         return $stack;
 296                 }
 297                 $outputs = [];
 298                 for ( $max = count( $stack ) - 1; $max > 0; ) {
 299                         /* Find all items under this entry */
 300                         $level = $stack[$max][1];
 301                         $working = [];
 302                         for ( $i = $max -1; $i >= 0; $i-- ) {
 303                                 if ( $stack[$i][1] > $level ) {
 304                                         $working[] = $stack[$i];
 305                                 } else {
 306                                         break;
 307                                 }
 308                         }
 309                         $working = $this->remapCallTree( array_reverse( $working ) );
 310                         $output = [];
 311                         foreach ( $working as $item ) {
 312                                 array_push( $output, $item );
 313                         }
 314                         array_unshift( $output, $stack[$max] );
 315                         $max = $i;
 316
 317                         array_unshift( $outputs, $output );
 318                 }
 319                 $final = [];
 320                 foreach ( $outputs as $output ) {
 321                         foreach ( $output as $item ) {
 322                                 $final[] = $item;
 323                         }
 324                 }
 325                 return $final;
 326         }
 327
 328         /**
 329          * Callback to get a formatted line for the call tree
 330          * @param array $entry
 331          * @return string
 332          */
 333         protected function getCallTreeLine( $entry ) {
 334                 // $entry has (name, level, stime, scpu, smem, etime, ecpu, emem)
 335                 list( $fname, $level, $startreal, , , $endreal ) = $entry;
 336                 $delta = $endreal - $startreal;
 337                 $space = str_repeat( ' ', $level );
 338                 # The ugly double sprintf is to work around a PHP bug,
 339                 # which has been fixed in recent releases.
 340                 return sprintf( "%10s %s %s\n",
 341                         trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
 342         }
 343
 344         /**
 345          * Populate collated data
 346          */
 347         protected function collateData() {
 348                 if ( $this->collateDone ) {
 349                         return;
 350                 }
 351                 $this->collateDone = true;
 352                 // Close opened profiling sections
 353                 while ( count( $this->workStack ) ) {
 354                         $this->profileOutInternal( 'close' );
 355                 }
 356
 357                 if ( $this->collateOnly ) {
 358                         return; // already collated as methods exited
 359                 }
 360
 361                 $this->collated = [];
 362
 363                 # Estimate profiling overhead
 364                 $oldEnd = $this->end;
 365                 $profileCount = count( $this->stack );
 366                 $this->calculateOverhead( $profileCount );
 367
 368                 # First, subtract the overhead!
 369                 $overheadTotal = $overheadMemory = $overheadInternal = [];
 370                 foreach ( $this->stack as $entry ) {
 371                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 372                         $fname = $entry[0];
 373                         $elapsed = $entry[5] - $entry[2];
 374                         $memchange = $entry[7] - $entry[4];
 375
 376                         if ( $fname === '-overhead-total' ) {
 377                                 $overheadTotal[] = $elapsed;
 378                                 $overheadMemory[] = max( 0, $memchange );
 379                         } elseif ( $fname === '-overhead-internal' ) {
 380                                 $overheadInternal[] = $elapsed;
 381                         }
 382                 }
 383                 $overheadTotal = $overheadTotal ?
 384                         array_sum( $overheadTotal ) / count( $overheadInternal ) : 0;
 385                 $overheadMemory = $overheadMemory ?
 386                         array_sum( $overheadMemory ) / count( $overheadInternal ) : 0;
 387                 $overheadInternal = $overheadInternal ?
 388                         array_sum( $overheadInternal ) / count( $overheadInternal ) : 0;
 389
 390                 # Collate
 391                 foreach ( $this->stack as $index => $entry ) {
 392                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 393                         $fname = $entry[0];
 394                         $elapsedCpu = $entry[6] - $entry[3];
 395                         $elapsedReal = $entry[5] - $entry[2];
 396                         $memchange = $entry[7] - $entry[4];
 397                         $subcalls = $this->calltreeCount( $this->stack, $index );
 398
 399                         if ( substr( $fname, 0, 9 ) !== '-overhead' ) {
 400                                 # Adjust for profiling overhead (except special values with elapsed=0)
 401                                 if ( $elapsed ) {
 402                                         $elapsed -= $overheadInternal;
 403                                         $elapsed -= ( $subcalls * $overheadTotal );
 404                                         $memchange -= ( $subcalls * $overheadMemory );
 405                                 }
 406                         }
 407
 408                         $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange );
 409                 }
 410
 411                 $this->collated['-overhead-total']['count'] = $profileCount;
 412                 arsort( $this->collated, SORT_NUMERIC );
 413
 414                 // Unclobber the end info map (the overhead checking alters it)
 415                 $this->end = $oldEnd;
 416         }
 417
 418         /**
 419          * Dummy calls to calculate profiling overhead
 420          *
 421          * @param int $profileCount
 422          */
 423         protected function calculateOverhead( $profileCount ) {
 424                 $this->profileInInternal( '-overhead-total' );
 425                 for ( $i = 0; $i < $profileCount; $i++ ) {
 426                         $this->profileInInternal( '-overhead-internal' );
 427                         $this->profileOutInternal( '-overhead-internal' );
 428                 }
 429                 $this->profileOutInternal( '-overhead-total' );
 430         }
 431
 432         /**
 433          * Counts the number of profiled function calls sitting under
 434          * the given point in the call graph. Not the most efficient algo.
 435          *
 436          * @param array $stack
 437          * @param int $start
 438          * @return int
 439          */
 440         protected function calltreeCount( $stack, $start ) {
 441                 $level = $stack[$start][1];
 442                 $count = 0;
 443                 for ( $i = $start -1; $i >= 0 && $stack[$i][1] > $level; $i-- ) {
 444                         $count ++;
 445                 }
 446                 return $count;
 447         }
 448
 449         /**
 450          * Get the initial time of the request, based on getrusage()
 451          *
 452          * @param string|bool $metric Metric to use, with the following possibilities:
 453          *   - user: User CPU time (without system calls)
 454          *   - cpu: Total CPU time (user and system calls)
 455          *   - wall (or any other string): elapsed time
 456          *   - false (default): will fall back to default metric
 457          * @return float
 458          */
 459         protected function getTime( $metric = 'wall' ) {
 460                 if ( $metric === 'cpu' || $metric === 'user' ) {
 461                         $ru = wfGetRusage();
 462                         if ( !$ru ) {
 463                                 return 0;
 464                         }
 465                         $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
 466                         if ( $metric === 'cpu' ) {
 467                                 # This is the time of system calls, added to the user time
 468                                 # it gives the total CPU time
 469                                 $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
 470                         }
 471                         return $time;
 472                 } else {
 473                         return microtime( true );
 474                 }
 475         }
 476
 477         /**
 478          * Add an entry in the debug log file
 479          *
 480          * @param string $s String to output
 481          */
 482         protected function debug( $s ) {
 483                 if ( function_exists( 'wfDebug' ) ) {
 484                         wfDebug( $s );
 485                 }
 486         }
 487
 488         /**
 489          * Add an entry in the debug log group
 490          *
 491          * @param string $group Group to send the message to
 492          * @param string $s String to output
 493          */
 494         protected function debugGroup( $group, $s ) {
 495                 if ( function_exists( 'wfDebugLog' ) ) {
 496                         wfDebugLog( $group, $s );
 497                 }
 498         }
 499 }
 500
 501 /**
 502  * Subclass ScopedCallback to avoid call_user_func_array(), which is slow
 503  *
 504  * This class should not be used outside of SectionProfiler
 505  */
 506 class SectionProfileCallback extends ScopedCallback {
 507         /** @var SectionProfiler */
 508         protected $profiler;
 509         /** @var string */
 510         protected $section;
 511
 512         /**
 513          * @param SectionProfiler $profiler
 514          * @param string $section
 515          */
 516         public function __construct( SectionProfiler $profiler, $section ) {
 517                 parent::__construct( null );
 518                 $this->profiler = $profiler;
 519                 $this->section = $section;
 520         }
 521
 522         function __destruct() {
 523                 $this->profiler->profileOutInternal( $this->section );
 524         }
 525 }