includes/profiler/Profiler.php

   1 <?php
   2 /**
   3  * Base class and functions for 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  * @defgroup Profiler Profiler
  23  */
  24
  25 /**
  26  * Get system resource usage of current request context.
  27  * Invokes the getrusage(2) system call, requesting RUSAGE_SELF if on PHP5
  28  * or RUSAGE_THREAD if on HHVM. Returns false if getrusage is not available.
  29  *
  30  * @since 1.24
  31  * @return array|bool Resource usage data or false if no data available.
  32  */
  33 function wfGetRusage() {
  34         if ( !function_exists( 'getrusage' ) ) {
  35                 return false;
  36         } elseif ( defined ( 'HHVM_VERSION' ) ) {
  37                 return getrusage( 2 /* RUSAGE_THREAD */ );
  38         } else {
  39                 return getrusage( 0 /* RUSAGE_SELF */ );
  40         }
  41 }
  42
  43 /**
  44  * Begin profiling of a function
  45  * @param string $functionname Name of the function we will profile
  46  */
  47 function wfProfileIn( $functionname ) {
  48         if ( Profiler::$__instance === null ) { // use this directly to reduce overhead
  49                 Profiler::instance();
  50         }
  51         if ( !( Profiler::$__instance instanceof ProfilerStub ) ) {
  52                 Profiler::$__instance->profileIn( $functionname );
  53         }
  54 }
  55
  56 /**
  57  * Stop profiling of a function
  58  * @param string $functionname Name of the function we have profiled
  59  */
  60 function wfProfileOut( $functionname = 'missing' ) {
  61         if ( Profiler::$__instance === null ) { // use this directly to reduce overhead
  62                 Profiler::instance();
  63         }
  64         if ( !( Profiler::$__instance instanceof ProfilerStub ) ) {
  65                 Profiler::$__instance->profileOut( $functionname );
  66         }
  67 }
  68
  69 /**
  70  * Class for handling function-scope profiling
  71  *
  72  * @since 1.22
  73  */
  74 class ProfileSection {
  75         protected $name; // string; method name
  76         protected $enabled = false; // boolean; whether profiling is enabled
  77
  78         /**
  79          * Begin profiling of a function and return an object that ends profiling of
  80          * the function when that object leaves scope. As long as the object is not
  81          * specifically linked to other objects, it will fall out of scope at the same
  82          * moment that the function to be profiled terminates.
  83          *
  84          * This is typically called like:
  85          * <code>$section = new ProfileSection( __METHOD__ );</code>
  86          *
  87          * @param string $name Name of the function to profile
  88          */
  89         public function __construct( $name ) {
  90                 $this->name = $name;
  91                 if ( Profiler::$__instance === null ) { // use this directly to reduce overhead
  92                         Profiler::instance();
  93                 }
  94                 if ( !( Profiler::$__instance instanceof ProfilerStub ) ) {
  95                         $this->enabled = true;
  96                         Profiler::$__instance->profileIn( $this->name );
  97                 }
  98         }
  99
 100         function __destruct() {
 101                 if ( $this->enabled ) {
 102                         Profiler::$__instance->profileOut( $this->name );
 103                 }
 104         }
 105 }
 106
 107 /**
 108  * Profiler base class that defines the interface and some trivial functionality
 109  *
 110  * @ingroup Profiler
 111  */
 112 abstract class Profiler {
 113         /** @var string|bool Profiler ID for bucketing data */
 114         protected $mProfileID = false;
 115         /** @var bool Whether MediaWiki is in a SkinTemplate output context */
 116         protected $mTemplated = false;
 117
 118         /** @var TransactionProfiler */
 119         protected $trxProfiler;
 120
 121         // @codingStandardsIgnoreStart PSR2.Classes.PropertyDeclaration.Underscore
 122         /** @var Profiler Do not call this outside Profiler and ProfileSection */
 123         public static $__instance = null;
 124         // @codingStandardsIgnoreEnd
 125
 126         /**
 127          * @param array $params
 128          */
 129         public function __construct( array $params ) {
 130                 if ( isset( $params['profileID'] ) ) {
 131                         $this->mProfileID = $params['profileID'];
 132                 }
 133                 $this->trxProfiler = new TransactionProfiler();
 134         }
 135
 136         /**
 137          * Singleton
 138          * @return Profiler
 139          */
 140         final public static function instance() {
 141                 if ( self::$__instance === null ) {
 142                         global $wgProfiler;
 143                         if ( is_array( $wgProfiler ) ) {
 144                                 if ( !isset( $wgProfiler['class'] ) ) {
 145                                         $class = 'ProfilerStub';
 146                                 } else {
 147                                         $class = $wgProfiler['class'];
 148                                 }
 149                                 self::$__instance = new $class( $wgProfiler );
 150                         } else {
 151                                 self::$__instance = new ProfilerStub( array() );
 152                         }
 153                 }
 154                 return self::$__instance;
 155         }
 156
 157         /**
 158          * Set the profiler to a specific profiler instance. Mostly for dumpHTML
 159          * @param Profiler $p
 160          */
 161         final public static function setInstance( Profiler $p ) {
 162                 self::$__instance = $p;
 163         }
 164
 165         /**
 166          * Return whether this a stub profiler
 167          *
 168          * @return bool
 169          */
 170         abstract public function isStub();
 171
 172         /**
 173          * Return whether this profiler stores data
 174          *
 175          * Called by Parser::braceSubstitution. If true, the parser will not
 176          * generate per-title profiling sections, to avoid overloading the
 177          * profiling data collector.
 178          *
 179          * @see Profiler::logData()
 180          * @return bool
 181          */
 182         abstract public function isPersistent();
 183
 184         /**
 185          * @param string $id
 186          */
 187         public function setProfileID( $id ) {
 188                 $this->mProfileID = $id;
 189         }
 190
 191         /**
 192          * @return string
 193          */
 194         public function getProfileID() {
 195                 if ( $this->mProfileID === false ) {
 196                         return wfWikiID();
 197                 } else {
 198                         return $this->mProfileID;
 199                 }
 200         }
 201
 202         /**
 203          * Called by wfProfieIn()
 204          *
 205          * @param string $functionname
 206          */
 207         abstract public function profileIn( $functionname );
 208
 209         /**
 210          * Called by wfProfieOut()
 211          *
 212          * @param string $functionname
 213          */
 214         abstract public function profileOut( $functionname );
 215
 216         /**
 217          * Mark a DB as in a transaction with one or more writes pending
 218          *
 219          * Note that there can be multiple connections to a single DB.
 220          *
 221          * @param string $server DB server
 222          * @param string $db DB name
 223          * @param string $id Resource ID string of connection
 224          */
 225         public function transactionWritingIn( $server, $db, $id = '' ) {
 226                 $this->trxProfiler->transactionWritingIn( $server, $db, $id );
 227         }
 228
 229         /**
 230          * Mark a DB as no longer in a transaction
 231          *
 232          * This will check if locks are possibly held for longer than
 233          * needed and log any affected transactions to a special DB log.
 234          * Note that there can be multiple connections to a single DB.
 235          *
 236          * @param string $server DB server
 237          * @param string $db DB name
 238          * @param string $id Resource ID string of connection
 239          */
 240         public function transactionWritingOut( $server, $db, $id = '' ) {
 241                 $this->trxProfiler->transactionWritingOut( $server, $db, $id );
 242         }
 243
 244         /**
 245          * Close opened profiling sections
 246          */
 247         abstract public function close();
 248
 249         /**
 250          * Log the data to some store or even the page output
 251          */
 252         abstract public function logData();
 253
 254         /**
 255          * Mark this call as templated or not
 256          *
 257          * @param bool $t
 258          */
 259         public function setTemplated( $t ) {
 260                 $this->mTemplated = $t;
 261         }
 262
 263         /**
 264          * Returns a profiling output to be stored in debug file
 265          *
 266          * @return string
 267          */
 268         abstract public function getOutput();
 269
 270         /**
 271          * @return array
 272          */
 273         abstract public function getRawData();
 274
 275         /**
 276          * Get the initial time of the request, based either on $wgRequestTime or
 277          * $wgRUstart. Will return null if not able to find data.
 278          *
 279          * @param string|bool $metric Metric to use, with the following possibilities:
 280          *   - user: User CPU time (without system calls)
 281          *   - cpu: Total CPU time (user and system calls)
 282          *   - wall (or any other string): elapsed time
 283          *   - false (default): will fall back to default metric
 284          * @return float|null
 285          */
 286         protected function getTime( $metric = 'wall' ) {
 287                 if ( $metric === 'cpu' || $metric === 'user' ) {
 288                         $ru = wfGetRusage();
 289                         if ( !$ru ) {
 290                                 return 0;
 291                         }
 292                         $time = $ru['ru_utime.tv_sec'] + $ru['ru_utime.tv_usec'] / 1e6;
 293                         if ( $metric === 'cpu' ) {
 294                                 # This is the time of system calls, added to the user time
 295                                 # it gives the total CPU time
 296                                 $time += $ru['ru_stime.tv_sec'] + $ru['ru_stime.tv_usec'] / 1e6;
 297                         }
 298                         return $time;
 299                 } else {
 300                         return microtime( true );
 301                 }
 302         }
 303
 304         /**
 305          * Get the initial time of the request, based either on $wgRequestTime or
 306          * $wgRUstart. Will return null if not able to find data.
 307          *
 308          * @param string|bool $metric Metric to use, with the following possibilities:
 309          *   - user: User CPU time (without system calls)
 310          *   - cpu: Total CPU time (user and system calls)
 311          *   - wall (or any other string): elapsed time
 312          *   - false (default): will fall back to default metric
 313          * @return float|null
 314          */
 315         protected function getInitialTime( $metric = 'wall' ) {
 316                 global $wgRequestTime, $wgRUstart;
 317
 318                 if ( $metric === 'cpu' || $metric === 'user' ) {
 319                         if ( !count( $wgRUstart ) ) {
 320                                 return null;
 321                         }
 322
 323                         $time = $wgRUstart['ru_utime.tv_sec'] + $wgRUstart['ru_utime.tv_usec'] / 1e6;
 324                         if ( $metric === 'cpu' ) {
 325                                 # This is the time of system calls, added to the user time
 326                                 # it gives the total CPU time
 327                                 $time += $wgRUstart['ru_stime.tv_sec'] + $wgRUstart['ru_stime.tv_usec'] / 1e6;
 328                         }
 329                         return $time;
 330                 } else {
 331                         if ( empty( $wgRequestTime ) ) {
 332                                 return null;
 333                         } else {
 334                                 return $wgRequestTime;
 335                         }
 336                 }
 337         }
 338
 339         /**
 340          * Add an entry in the debug log file
 341          *
 342          * @param string $s String to output
 343          */
 344         protected function debug( $s ) {
 345                 if ( function_exists( 'wfDebug' ) ) {
 346                         wfDebug( $s );
 347                 }
 348         }
 349
 350         /**
 351          * Add an entry in the debug log group
 352          *
 353          * @param string $group Group to send the message to
 354          * @param string $s String to output
 355          */
 356         protected function debugGroup( $group, $s ) {
 357                 if ( function_exists( 'wfDebugLog' ) ) {
 358                         wfDebugLog( $group, $s );
 359                 }
 360         }
 361 }
 362
 363 /**
 364  * Helper class that detects high-contention DB queries via profiling calls
 365  *
 366  * This class is meant to work with a Profiler, as the later already knows
 367  * when methods start and finish (which may take place during transactions).
 368  *
 369  * @since 1.24
 370  */
 371 class TransactionProfiler {
 372         /** @var float Seconds */
 373         protected $mDBLockThreshold = 3.0;
 374         /** @var array DB/server name => (active trx count, time, DBs involved) */
 375         protected $mDBTrxHoldingLocks = array();
 376         /** @var array DB/server name => list of (function name, elapsed time) */
 377         protected $mDBTrxMethodTimes = array();
 378
 379         /**
 380          * Mark a DB as in a transaction with one or more writes pending
 381          *
 382          * Note that there can be multiple connections to a single DB.
 383          *
 384          * @param string $server DB server
 385          * @param string $db DB name
 386          * @param string $id ID string of transaction
 387          */
 388         public function transactionWritingIn( $server, $db, $id ) {
 389                 $name = "{$server} ({$db}) (TRX#$id)";
 390                 if ( isset( $this->mDBTrxHoldingLocks[$name] ) ) {
 391                         wfDebugLog( 'DBPerformance', "Nested transaction for '$name' - out of sync." );
 392                 }
 393                 $this->mDBTrxHoldingLocks[$name] =
 394                         array( 'start' => microtime( true ), 'conns' => array() );
 395                 $this->mDBTrxMethodTimes[$name] = array();
 396
 397                 foreach ( $this->mDBTrxHoldingLocks as $name => &$info ) {
 398                         $info['conns'][$name] = 1; // track all DBs in transactions for this transaction
 399                 }
 400         }
 401
 402         /**
 403          * Register the name and time of a method for slow DB trx detection
 404          *
 405          * This method is only to be called by the Profiler class as methods finish
 406          *
 407          * @param string $method Function name
 408          * @param float $realtime Wal time ellapsed
 409          */
 410         public function recordFunctionCompletion( $method, $realtime ) {
 411                 if ( !$this->mDBTrxHoldingLocks ) {
 412                         return; // short-circuit
 413                 // @todo hardcoded check is a tad janky (what about FOR UPDATE?)
 414                 } elseif ( !preg_match( '/^query-m: (?!SELECT)/', $method )
 415                         && $realtime < $this->mDBLockThreshold
 416                 ) {
 417                         return; // not a DB master query nor slow enough
 418                 }
 419                 $now = microtime( true );
 420                 foreach ( $this->mDBTrxHoldingLocks as $name => $info ) {
 421                         // Hacky check to exclude entries from before the first TRX write
 422                         if ( ( $now - $realtime ) >= $info['start'] ) {
 423                                 $this->mDBTrxMethodTimes[$name][] = array( $method, $realtime );
 424                         }
 425                 }
 426         }
 427
 428         /**
 429          * Mark a DB as no longer in a transaction
 430          *
 431          * This will check if locks are possibly held for longer than
 432          * needed and log any affected transactions to a special DB log.
 433          * Note that there can be multiple connections to a single DB.
 434          *
 435          * @param string $server DB server
 436          * @param string $db DB name
 437          * @param string $id ID string of transaction
 438          */
 439         public function transactionWritingOut( $server, $db, $id ) {
 440                 $name = "{$server} ({$db}) (TRX#$id)";
 441                 if ( !isset( $this->mDBTrxMethodTimes[$name] ) ) {
 442                         wfDebugLog( 'DBPerformance', "Detected no transaction for '$name' - out of sync." );
 443                         return;
 444                 }
 445                 $slow = false;
 446                 foreach ( $this->mDBTrxMethodTimes[$name] as $info ) {
 447                         $realtime = $info[1];
 448                         if ( $realtime >= $this->mDBLockThreshold ) {
 449                                 $slow = true;
 450                                 break;
 451                         }
 452                 }
 453                 if ( $slow ) {
 454                         $dbs = implode( ', ', array_keys( $this->mDBTrxHoldingLocks[$name]['conns'] ) );
 455                         $msg = "Sub-optimal transaction on DB(s) [{$dbs}]:\n";
 456                         foreach ( $this->mDBTrxMethodTimes[$name] as $i => $info ) {
 457                                 list( $method, $realtime ) = $info;
 458                                 $msg .= sprintf( "%d\t%.6f\t%s\n", $i, $realtime, $method );
 459                         }
 460                         wfDebugLog( 'DBPerformance', $msg );
 461                 }
 462                 unset( $this->mDBTrxHoldingLocks[$name] );
 463                 unset( $this->mDBTrxMethodTimes[$name] );
 464         }
 465 }