SectionProfiler::getCallTreeLine()   A
last analyzed

Complexity

Conditions 1
Paths 1

Size

Total Lines 10
Code Lines 6

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 1
eloc 6
nc 1
nop 1
dl 0
loc 10
rs 9.4285
c 0
b 0
f 0
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;
0 ignored issues
show
Bug introduced by
This use statement conflicts with another class in this namespace, ScopedCallback.

Let’s assume that you have a directory layout like this:

.
|-- OtherDir
|   |-- Bar.php
|   `-- Foo.php
`-- SomeDir
    `-- Foo.php

and let’s assume the following content of Bar.php:

// Bar.php
namespace OtherDir;

use SomeDir\Foo; // This now conflicts the class OtherDir\Foo

If both files OtherDir/Foo.php and SomeDir/Foo.php are loaded in the same runtime, you will see a PHP error such as the following:

PHP Fatal error:  Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.php

However, as OtherDir/Foo.php does not necessarily have to be loaded and the error is only triggered if it is loaded before OtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias:

// Bar.php
namespace OtherDir;

use SomeDir\Foo as SomeDirFoo; // There is no conflict anymore.
Loading history...
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;
0 ignored issues
show
Documentation Bug introduced by
It seems like null of type null is incompatible with the declared type array of property $start.

Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.

Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..

Loading history...
141
		$this->end = null;
0 ignored issues
show
Documentation Bug introduced by
It seems like null of type null is incompatible with the declared type array of property $end.

Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.

Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..

Loading history...
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 View Code Duplication
			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 View Code Duplication
			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;
0 ignored issues
show
Bug introduced by
The variable $elapsed does not seem to be defined for all execution paths leading up to this point.

If you define a variable conditionally, it can happen that it is not defined for all execution paths.

Let’s take a look at an example:

function myFunction($a) {
    switch ($a) {
        case 'foo':
            $x = 1;
            break;

        case 'bar':
            $x = 2;
            break;
    }

    // $x is potentially undefined here.
    echo $x;
}

In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.

Available Fixes

  1. Check for existence of the variable explicitly:

    function myFunction($a) {
        switch ($a) {
            case 'foo':
                $x = 1;
                break;
    
            case 'bar':
                $x = 2;
                break;
        }
    
        if (isset($x)) { // Make sure it's always set.
            echo $x;
        }
    }
    
  2. Define a default value for the variable:

    function myFunction($a) {
        $x = ''; // Set a default which gets overridden for certain paths.
        switch ($a) {
            case 'foo':
                $x = 1;
                break;
    
            case 'bar':
                $x = 2;
                break;
        }
    
        echo $x;
    }
    
  3. Add a value for the missing path:

    function myFunction($a) {
        switch ($a) {
            case 'foo':
                $x = 1;
                break;
    
            case 'bar':
                $x = 2;
                break;
    
            // We add support for the missing case.
            default:
                $x = '';
                break;
        }
    
        echo $x;
    }
    
Loading history...
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
}
526