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
  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 List of resolved profile calls with start/end data */
  32         protected $stack = array();
  33         /** @var array Queue of open profile calls with start data */
  34         protected $workStack = array();
  35
  36         /** @var array Map of (function name => aggregate data array) */
  37         protected $collated = array();
  38         /** @var bool */
  39         protected $collateDone = false;
  40         /** @var bool Whether to collect the full stack trace or just aggregates */
  41         protected $collateOnly = true;
  42
  43         /** @var array Cache of a standard broken collation entry */
  44         protected $errorEntry;
  45
  46         /**
  47          * @param array $params
  48          */
  49         public function __construct( array $params = array() ) {
  50                 $this->errorEntry = $this->getErrorEntry();
  51                 $this->collateOnly = empty( $params['trace'] );
  52         }
  53
  54         /**
  55          * @param string $section
  56          * @return ScopedCallback
  57          */
  58         public function scopedProfileIn( $section ) {
  59                 $this->profileInInternal( $section );
  60
  61                 $that = $this;
  62                 return new ScopedCallback( function() use ( $that, $section ) {
  63                         $that->profileOutInternal( $section );
  64                 } );
  65         }
  66
  67         /**
  68          * @param ScopedCallback $section
  69          */
  70         public function scopedProfileOut( ScopedCallback &$section ) {
  71                 $section = null;
  72         }
  73
  74         /**
  75          * Get the aggregated inclusive profiling data for each method
  76          *
  77          * The percent time for each time is based on the current "total" time
  78          * used is based on all methods so far. This method can therefore be
  79          * called several times in between several profiling calls without the
  80          * delays in usage of the profiler skewing the results. A "-total" entry
  81          * is always included in the results.
  82          *
  83          * @return array List of method entries arrays, each having:
  84          *   - name    : method name
  85          *   - calls   : the number of invoking calls
  86          *   - real    : real time ellapsed (ms)
  87          *   - %real   : percent real time
  88          *   - cpu     : real time ellapsed (ms)
  89          *   - %cpu    : percent real time
  90          *   - memory  : memory used (bytes)
  91          *   - %memory : percent memory used
  92          */
  93         public function getFunctionStats() {
  94                 $this->collateData();
  95
  96                 $totalCpu = 0.0;
  97                 $totalReal = 0.0;
  98                 $totalMem = 0;
  99                 foreach ( $this->collated as $fname => $data ) {
 100                         $totalCpu += $data['cpu'];
 101                         $totalReal += $data['real'];
 102                         $totalMem += $data['memory'];
 103                 }
 104
 105                 $profile = array();
 106                 foreach ( $this->collated as $fname => $data ) {
 107                         $profile[] = array(
 108                                 'name' => $fname,
 109                                 'calls' => $data['count'],
 110                                 'real' => $data['real'] * 1000,
 111                                 '%real' => $totalReal ? 100 * $data['real'] / $totalReal : 0,
 112                                 'cpu' => $data['cpu'] * 1000,
 113                                 '%cpu' => $totalCpu ? 100 * $data['cpu'] / $totalCpu : 0,
 114                                 'memory' => $data['memory'],
 115                                 '%memory' => $totalMem ? 100 * $data['memory'] / $totalMem : 0,
 116                         );
 117                 }
 118
 119                 $profile[] = array(
 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                 );
 129
 130                 return $profile;
 131         }
 132
 133         /**
 134          * @return array Initial collation entry
 135          */
 136         protected function getZeroEntry() {
 137                 return array(
 138                         'cpu'      => 0.0,
 139                         'real'     => 0.0,
 140                         'memory'   => 0,
 141                         'count'    => 0
 142                 );
 143         }
 144
 145         /**
 146          * @return array Initial collation entry for errors
 147          */
 148         protected function getErrorEntry() {
 149                 $entry = $this->getZeroEntry();
 150                 $entry['count'] = 1;
 151                 return $entry;
 152         }
 153
 154         /**
 155          * Update the collation entry for a given method name
 156          *
 157          * @param string $name
 158          * @param float $elapsedCpu
 159          * @param float $elapsedReal
 160          * @param int $memChange
 161          */
 162         protected function updateEntry( $name, $elapsedCpu, $elapsedReal, $memChange ) {
 163                 $entry =& $this->collated[$name];
 164                 if ( !is_array( $entry ) ) {
 165                         $entry = $this->getZeroEntry();
 166                         $this->collated[$name] =& $entry;
 167                 }
 168                 $entry['cpu'] += $elapsedCpu;
 169                 $entry['real'] += $elapsedReal;
 170                 $entry['memory'] += $memChange > 0 ? $memChange : 0;
 171                 $entry['count']++;
 172         }
 173
 174         /**
 175          * This method should not be called outside SectionProfiler
 176          *
 177          * @param string $functionname
 178          */
 179         public function profileInInternal( $functionname ) {
 180                 $this->workStack[] = array(
 181                         $functionname,
 182                         count( $this->workStack ),
 183                         $this->getTime( 'time' ),
 184                         $this->getTime( 'cpu' ),
 185                         memory_get_usage()
 186                 );
 187         }
 188
 189         /**
 190          * This method should not be called outside SectionProfiler
 191          *
 192          * @param string $functionname
 193          */
 194         public function profileOutInternal( $functionname ) {
 195                 $item = array_pop( $this->workStack );
 196                 if ( $item === null ) {
 197                         $this->debugGroup( 'profileerror', "Profiling error: $functionname" );
 198                         return;
 199                 }
 200                 list( $ofname, /* $ocount */, $ortime, $octime, $omem ) = $item;
 201
 202                 if ( $functionname === 'close' ) {
 203                         $message = "Profile section ended by close(): {$ofname}";
 204                         $this->debugGroup( 'profileerror', $message );
 205                         if ( $this->collateOnly ) {
 206                                 $this->collated[$message] = $this->errorEntry;
 207                         } else {
 208                                 $this->stack[] = array( $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 );
 209                         }
 210                         $functionname = $ofname;
 211                 } elseif ( $ofname !== $functionname ) {
 212                         $message = "Profiling error: in({$ofname}), out($functionname)";
 213                         $this->debugGroup( 'profileerror', $message );
 214                         if ( $this->collateOnly ) {
 215                                 $this->collated[$message] = $this->errorEntry;
 216                         } else {
 217                                 $this->stack[] = array( $message, 0, 0.0, 0.0, 0, 0.0, 0.0, 0 );
 218                         }
 219                 }
 220                 $realTime = $this->getTime( 'wall' );
 221                 $cpuTime = $this->getTime( 'cpu' );
 222                 if ( $this->collateOnly ) {
 223                         $elapsedcpu = $cpuTime - $octime;
 224                         $elapsedreal = $realTime - $ortime;
 225                         $memchange = memory_get_usage() - $omem;
 226                         $this->updateEntry( $functionname, $elapsedcpu, $elapsedreal, $memchange );
 227                 } else {
 228                         $this->stack[] = array_merge( $item,
 229                                 array( $realTime, $cpuTime,     memory_get_usage() ) );
 230                 }
 231         }
 232
 233         /**
 234          * Returns a tree of function calls with their real times
 235          * @return string
 236          */
 237         public function getCallTreeReport() {
 238                 if ( $this->collateOnly ) {
 239                         throw new Exception( "Tree is only available for trace profiling." );
 240                 }
 241                 return implode( '', array_map(
 242                         array( $this, 'getCallTreeLine' ), $this->remapCallTree( $this->stack )
 243                 ) );
 244         }
 245
 246         /**
 247          * Recursive function the format the current profiling array into a tree
 248          *
 249          * @param array $stack Profiling array
 250          * @return array
 251          */
 252         protected function remapCallTree( array $stack ) {
 253                 if ( count( $stack ) < 2 ) {
 254                         return $stack;
 255                 }
 256                 $outputs = array();
 257                 for ( $max = count( $stack ) - 1; $max > 0; ) {
 258                         /* Find all items under this entry */
 259                         $level = $stack[$max][1];
 260                         $working = array();
 261                         for ( $i = $max -1; $i >= 0; $i-- ) {
 262                                 if ( $stack[$i][1] > $level ) {
 263                                         $working[] = $stack[$i];
 264                                 } else {
 265                                         break;
 266                                 }
 267                         }
 268                         $working = $this->remapCallTree( array_reverse( $working ) );
 269                         $output = array();
 270                         foreach ( $working as $item ) {
 271                                 array_push( $output, $item );
 272                         }
 273                         array_unshift( $output, $stack[$max] );
 274                         $max = $i;
 275
 276                         array_unshift( $outputs, $output );
 277                 }
 278                 $final = array();
 279                 foreach ( $outputs as $output ) {
 280                         foreach ( $output as $item ) {
 281                                 $final[] = $item;
 282                         }
 283                 }
 284                 return $final;
 285         }
 286
 287         /**
 288          * Callback to get a formatted line for the call tree
 289          * @param array $entry
 290          * @return string
 291          */
 292         protected function getCallTreeLine( $entry ) {
 293                 // $entry has (name, level, stime, scpu, smem, etime, ecpu, emem)
 294                 list( $fname, $level, $startreal, , , $endreal ) = $entry;
 295                 $delta = $endreal - $startreal;
 296                 $space = str_repeat( ' ', $level );
 297                 # The ugly double sprintf is to work around a PHP bug,
 298                 # which has been fixed in recent releases.
 299                 return sprintf( "%10s %s %s\n",
 300                         trim( sprintf( "%7.3f", $delta * 1000.0 ) ), $space, $fname );
 301         }
 302
 303         /**
 304          * Populate collated data
 305          */
 306         protected function collateData() {
 307                 if ( $this->collateDone ) {
 308                         return;
 309                 }
 310                 $this->collateDone = true;
 311                 // Close opened profiling sections
 312                 while ( count( $this->workStack ) ) {
 313                         $this->profileOutInternal( 'close' );
 314                 }
 315
 316                 if ( $this->collateOnly ) {
 317                         return; // already collated as methods exited
 318                 }
 319
 320                 $this->collated = array();
 321
 322                 # Estimate profiling overhead
 323                 $profileCount = count( $this->stack );
 324                 $this->calculateOverhead( $profileCount );
 325
 326                 # First, subtract the overhead!
 327                 $overheadTotal = $overheadMemory = $overheadInternal = array();
 328                 foreach ( $this->stack as $entry ) {
 329                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 330                         $fname = $entry[0];
 331                         $elapsed = $entry[5] - $entry[2];
 332                         $memchange = $entry[7] - $entry[4];
 333
 334                         if ( $fname === '-overhead-total' ) {
 335                                 $overheadTotal[] = $elapsed;
 336                                 $overheadMemory[] = max( 0, $memchange );
 337                         } elseif ( $fname === '-overhead-internal' ) {
 338                                 $overheadInternal[] = $elapsed;
 339                         }
 340                 }
 341                 $overheadTotal = $overheadTotal ?
 342                         array_sum( $overheadTotal ) / count( $overheadInternal ) : 0;
 343                 $overheadMemory = $overheadMemory ?
 344                         array_sum( $overheadMemory ) / count( $overheadInternal ) : 0;
 345                 $overheadInternal = $overheadInternal ?
 346                         array_sum( $overheadInternal ) / count( $overheadInternal ) : 0;
 347
 348                 # Collate
 349                 foreach ( $this->stack as $index => $entry ) {
 350                         // $entry is (name,pos,rtime0,cputime0,mem0,rtime1,cputime1,mem1)
 351                         $fname = $entry[0];
 352                         $elapsedCpu = $entry[6] - $entry[3];
 353                         $elapsedReal = $entry[5] - $entry[2];
 354                         $memchange = $entry[7] - $entry[4];
 355                         $subcalls = $this->calltreeCount( $this->stack, $index );
 356
 357                         if ( substr( $fname, 0, 9 ) !== '-overhead' ) {
 358                                 # Adjust for profiling overhead (except special values with elapsed=0
 359                                 if ( $elapsed ) {
 360                                         $elapsed -= $overheadInternal;
 361                                         $elapsed -= ( $subcalls * $overheadTotal );
 362                                         $memchange -= ( $subcalls * $overheadMemory );
 363                                 }
 364                         }
 365
 366                         $this->updateEntry( $fname, $elapsedCpu, $elapsedReal, $memchange );
 367                 }
 368
 369                 $this->collated['-overhead-total']['count'] = $profileCount;
 370                 arsort( $this->collated, SORT_NUMERIC );
 371         }
 372
 373         /**
 374          * Dummy calls to calculate profiling overhead
 375          *
 376          * @param int $profileCount
 377          */
 378         protected function calculateOverhead( $profileCount ) {
 379                 $this->profileInInternal( '-overhead-total' );
 380                 for ( $i = 0; $i < $profileCount; $i++ ) {
 381                         $this->profileInInternal( '-overhead-internal' );
 382                         $this->profileOutInternal( '-overhead-internal' );
 383                 }
 384                 $this->profileOutInternal( '-overhead-total' );
 385         }
 386
 387         /**
 388          * Counts the number of profiled function calls sitting under
 389          * the given point in the call graph. Not the most efficient algo.
 390          *
 391          * @param array $stack
 392          * @param int $start
 393          * @return int
 394          */
 395         protected function calltreeCount( $stack, $start ) {
 396                 $level = $stack[$start][1];
 397                 $count = 0;
 398                 for ( $i = $start -1; $i >= 0 && $stack[$i][1] > $level; $i-- ) {
 399                         $count ++;
 400                 }
 401                 return $count;
 402         }
 403
 404         /**
 405          * Get the initial time of the request, based either on $wgRequestTime or
 406          * $wgRUstart. Will return null if not able to find data.
 407          *
 408          * @param string|bool $metric Metric to use, with the following possibilities:
 409          *   - user: User CPU time (without system calls)
 410          *   - cpu: Total CPU time (user and system calls)
 411          *   - wall (or any other string): elapsed time
 412          *   - false (default): will fall back to default metric
 413          * @return float|null
 414          */
 415         protected function getTime( $metric = 'wall' ) {
 416                 if ( $metric === 'cpu' || $metric === 'user' ) {
 417                         $ru = wfGetRusage();
 418                         if ( !$ru ) {
 419                                 return 0;
 420                         }
 421                         $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
 422                         if ( $metric === 'cpu' ) {
 423                                 # This is the time of system calls, added to the user time
 424                                 # it gives the total CPU time
 425                                 $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
 426                         }
 427                         return $time;
 428                 } else {
 429                         return microtime( true );
 430                 }
 431         }
 432
 433         /**
 434          * Add an entry in the debug log file
 435          *
 436          * @param string $s String to output
 437          */
 438         protected function debug( $s ) {
 439                 if ( function_exists( 'wfDebug' ) ) {
 440                         wfDebug( $s );
 441                 }
 442         }
 443
 444         /**
 445          * Add an entry in the debug log group
 446          *
 447          * @param string $group Group to send the message to
 448          * @param string $s String to output
 449          */
 450         protected function debugGroup( $group, $s ) {
 451                 if ( function_exists( 'wfDebugLog' ) ) {
 452                         wfDebugLog( $group, $s );
 453                 }
 454         }
 455 }