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1 | package Benchmark; |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | Benchmark - benchmark running times of Perl code | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | use Benchmark qw(:all) ; | |
10 | ||
11 | timethis ($count, "code"); | |
12 | ||
13 | # Use Perl code in strings... | |
14 | timethese($count, { | |
15 | 'Name1' => '...code1...', | |
16 | 'Name2' => '...code2...', | |
17 | }); | |
18 | ||
19 | # ... or use subroutine references. | |
20 | timethese($count, { | |
21 | 'Name1' => sub { ...code1... }, | |
22 | 'Name2' => sub { ...code2... }, | |
23 | }); | |
24 | ||
25 | # cmpthese can be used both ways as well | |
26 | cmpthese($count, { | |
27 | 'Name1' => '...code1...', | |
28 | 'Name2' => '...code2...', | |
29 | }); | |
30 | ||
31 | cmpthese($count, { | |
32 | 'Name1' => sub { ...code1... }, | |
33 | 'Name2' => sub { ...code2... }, | |
34 | }); | |
35 | ||
36 | # ...or in two stages | |
37 | $results = timethese($count, | |
38 | { | |
39 | 'Name1' => sub { ...code1... }, | |
40 | 'Name2' => sub { ...code2... }, | |
41 | }, | |
42 | 'none' | |
43 | ); | |
44 | cmpthese( $results ) ; | |
45 | ||
46 | $t = timeit($count, '...other code...') | |
47 | print "$count loops of other code took:",timestr($t),"\n"; | |
48 | ||
49 | $t = countit($time, '...other code...') | |
50 | $count = $t->iters ; | |
51 | print "$count loops of other code took:",timestr($t),"\n"; | |
52 | ||
53 | =head1 DESCRIPTION | |
54 | ||
55 | The Benchmark module encapsulates a number of routines to help you | |
56 | figure out how long it takes to execute some code. | |
57 | ||
58 | timethis - run a chunk of code several times | |
59 | ||
60 | timethese - run several chunks of code several times | |
61 | ||
62 | cmpthese - print results of timethese as a comparison chart | |
63 | ||
64 | timeit - run a chunk of code and see how long it goes | |
65 | ||
66 | countit - see how many times a chunk of code runs in a given time | |
67 | ||
68 | ||
69 | =head2 Methods | |
70 | ||
71 | =over 10 | |
72 | ||
73 | =item new | |
74 | ||
75 | Returns the current time. Example: | |
76 | ||
77 | use Benchmark; | |
78 | $t0 = new Benchmark; | |
79 | # ... your code here ... | |
80 | $t1 = new Benchmark; | |
81 | $td = timediff($t1, $t0); | |
82 | print "the code took:",timestr($td),"\n"; | |
83 | ||
84 | =item debug | |
85 | ||
86 | Enables or disable debugging by setting the C<$Benchmark::Debug> flag: | |
87 | ||
88 | debug Benchmark 1; | |
89 | $t = timeit(10, ' 5 ** $Global '); | |
90 | debug Benchmark 0; | |
91 | ||
92 | =item iters | |
93 | ||
94 | Returns the number of iterations. | |
95 | ||
96 | =back | |
97 | ||
98 | =head2 Standard Exports | |
99 | ||
100 | The following routines will be exported into your namespace | |
101 | if you use the Benchmark module: | |
102 | ||
103 | =over 10 | |
104 | ||
105 | =item timeit(COUNT, CODE) | |
106 | ||
107 | Arguments: COUNT is the number of times to run the loop, and CODE is | |
108 | the code to run. CODE may be either a code reference or a string to | |
109 | be eval'd; either way it will be run in the caller's package. | |
110 | ||
111 | Returns: a Benchmark object. | |
112 | ||
113 | =item timethis ( COUNT, CODE, [ TITLE, [ STYLE ]] ) | |
114 | ||
115 | Time COUNT iterations of CODE. CODE may be a string to eval or a | |
116 | code reference; either way the CODE will run in the caller's package. | |
117 | Results will be printed to STDOUT as TITLE followed by the times. | |
118 | TITLE defaults to "timethis COUNT" if none is provided. STYLE | |
119 | determines the format of the output, as described for timestr() below. | |
120 | ||
121 | The COUNT can be zero or negative: this means the I<minimum number of | |
122 | CPU seconds> to run. A zero signifies the default of 3 seconds. For | |
123 | example to run at least for 10 seconds: | |
124 | ||
125 | timethis(-10, $code) | |
126 | ||
127 | or to run two pieces of code tests for at least 3 seconds: | |
128 | ||
129 | timethese(0, { test1 => '...', test2 => '...'}) | |
130 | ||
131 | CPU seconds is, in UNIX terms, the user time plus the system time of | |
132 | the process itself, as opposed to the real (wallclock) time and the | |
133 | time spent by the child processes. Less than 0.1 seconds is not | |
134 | accepted (-0.01 as the count, for example, will cause a fatal runtime | |
135 | exception). | |
136 | ||
137 | Note that the CPU seconds is the B<minimum> time: CPU scheduling and | |
138 | other operating system factors may complicate the attempt so that a | |
139 | little bit more time is spent. The benchmark output will, however, | |
140 | also tell the number of C<$code> runs/second, which should be a more | |
141 | interesting number than the actually spent seconds. | |
142 | ||
143 | Returns a Benchmark object. | |
144 | ||
145 | =item timethese ( COUNT, CODEHASHREF, [ STYLE ] ) | |
146 | ||
147 | The CODEHASHREF is a reference to a hash containing names as keys | |
148 | and either a string to eval or a code reference for each value. | |
149 | For each (KEY, VALUE) pair in the CODEHASHREF, this routine will | |
150 | call | |
151 | ||
152 | timethis(COUNT, VALUE, KEY, STYLE) | |
153 | ||
154 | The routines are called in string comparison order of KEY. | |
155 | ||
156 | The COUNT can be zero or negative, see timethis(). | |
157 | ||
158 | Returns a hash of Benchmark objects, keyed by name. | |
159 | ||
160 | =item timediff ( T1, T2 ) | |
161 | ||
162 | Returns the difference between two Benchmark times as a Benchmark | |
163 | object suitable for passing to timestr(). | |
164 | ||
165 | =item timestr ( TIMEDIFF, [ STYLE, [ FORMAT ] ] ) | |
166 | ||
167 | Returns a string that formats the times in the TIMEDIFF object in | |
168 | the requested STYLE. TIMEDIFF is expected to be a Benchmark object | |
169 | similar to that returned by timediff(). | |
170 | ||
171 | STYLE can be any of 'all', 'none', 'noc', 'nop' or 'auto'. 'all' shows | |
172 | each of the 5 times available ('wallclock' time, user time, system time, | |
173 | user time of children, and system time of children). 'noc' shows all | |
174 | except the two children times. 'nop' shows only wallclock and the | |
175 | two children times. 'auto' (the default) will act as 'all' unless | |
176 | the children times are both zero, in which case it acts as 'noc'. | |
177 | 'none' prevents output. | |
178 | ||
179 | FORMAT is the L<printf(3)>-style format specifier (without the | |
180 | leading '%') to use to print the times. It defaults to '5.2f'. | |
181 | ||
182 | =back | |
183 | ||
184 | =head2 Optional Exports | |
185 | ||
186 | The following routines will be exported into your namespace | |
187 | if you specifically ask that they be imported: | |
188 | ||
189 | =over 10 | |
190 | ||
191 | =item clearcache ( COUNT ) | |
192 | ||
193 | Clear the cached time for COUNT rounds of the null loop. | |
194 | ||
195 | =item clearallcache ( ) | |
196 | ||
197 | Clear all cached times. | |
198 | ||
199 | =item cmpthese ( COUT, CODEHASHREF, [ STYLE ] ) | |
200 | ||
201 | =item cmpthese ( RESULTSHASHREF, [ STYLE ] ) | |
202 | ||
203 | Optionally calls timethese(), then outputs comparison chart. This: | |
204 | ||
205 | cmpthese( -1, { a => "++\$i", b => "\$i *= 2" } ) ; | |
206 | ||
207 | outputs a chart like: | |
208 | ||
209 | Rate b a | |
210 | b 2831802/s -- -61% | |
211 | a 7208959/s 155% -- | |
212 | ||
213 | This chart is sorted from slowest to fastest, and shows the percent speed | |
214 | difference between each pair of tests. | |
215 | ||
216 | c<cmpthese> can also be passed the data structure that timethese() returns: | |
217 | ||
218 | $results = timethese( -1, { a => "++\$i", b => "\$i *= 2" } ) ; | |
219 | cmpthese( $results ); | |
220 | ||
221 | in case you want to see both sets of results. | |
222 | ||
223 | Returns a reference to an ARRAY of rows, each row is an ARRAY of cells from the | |
224 | above chart, including labels. This: | |
225 | ||
226 | my $rows = cmpthese( -1, { a => '++$i', b => '$i *= 2' }, "none" ); | |
227 | ||
228 | returns a data structure like: | |
229 | ||
230 | [ | |
231 | [ '', 'Rate', 'b', 'a' ], | |
232 | [ 'b', '2885232/s', '--', '-59%' ], | |
233 | [ 'a', '7099126/s', '146%', '--' ], | |
234 | ] | |
235 | ||
236 | B<NOTE>: This result value differs from previous versions, which returned | |
237 | the C<timethese()> result structure. If you want that, just use the two | |
238 | statement C<timethese>...C<cmpthese> idiom shown above. | |
239 | ||
240 | Incidently, note the variance in the result values between the two examples; | |
241 | this is typical of benchmarking. If this were a real benchmark, you would | |
242 | probably want to run a lot more iterations. | |
243 | ||
244 | =item countit(TIME, CODE) | |
245 | ||
246 | Arguments: TIME is the minimum length of time to run CODE for, and CODE is | |
247 | the code to run. CODE may be either a code reference or a string to | |
248 | be eval'd; either way it will be run in the caller's package. | |
249 | ||
250 | TIME is I<not> negative. countit() will run the loop many times to | |
251 | calculate the speed of CODE before running it for TIME. The actual | |
252 | time run for will usually be greater than TIME due to system clock | |
253 | resolution, so it's best to look at the number of iterations divided | |
254 | by the times that you are concerned with, not just the iterations. | |
255 | ||
256 | Returns: a Benchmark object. | |
257 | ||
258 | =item disablecache ( ) | |
259 | ||
260 | Disable caching of timings for the null loop. This will force Benchmark | |
261 | to recalculate these timings for each new piece of code timed. | |
262 | ||
263 | =item enablecache ( ) | |
264 | ||
265 | Enable caching of timings for the null loop. The time taken for COUNT | |
266 | rounds of the null loop will be calculated only once for each | |
267 | different COUNT used. | |
268 | ||
269 | =item timesum ( T1, T2 ) | |
270 | ||
271 | Returns the sum of two Benchmark times as a Benchmark object suitable | |
272 | for passing to timestr(). | |
273 | ||
274 | =back | |
275 | ||
276 | =head1 NOTES | |
277 | ||
278 | The data is stored as a list of values from the time and times | |
279 | functions: | |
280 | ||
281 | ($real, $user, $system, $children_user, $children_system, $iters) | |
282 | ||
283 | in seconds for the whole loop (not divided by the number of rounds). | |
284 | ||
285 | The timing is done using time(3) and times(3). | |
286 | ||
287 | Code is executed in the caller's package. | |
288 | ||
289 | The time of the null loop (a loop with the same | |
290 | number of rounds but empty loop body) is subtracted | |
291 | from the time of the real loop. | |
292 | ||
293 | The null loop times can be cached, the key being the | |
294 | number of rounds. The caching can be controlled using | |
295 | calls like these: | |
296 | ||
297 | clearcache($key); | |
298 | clearallcache(); | |
299 | ||
300 | disablecache(); | |
301 | enablecache(); | |
302 | ||
303 | Caching is off by default, as it can (usually slightly) decrease | |
304 | accuracy and does not usually noticably affect runtimes. | |
305 | ||
306 | =head1 EXAMPLES | |
307 | ||
308 | For example, | |
309 | ||
310 | use Benchmark qw( cmpthese ) ; | |
311 | $x = 3; | |
312 | cmpthese( -5, { | |
313 | a => sub{$x*$x}, | |
314 | b => sub{$x**2}, | |
315 | } ); | |
316 | ||
317 | outputs something like this: | |
318 | ||
319 | Benchmark: running a, b, each for at least 5 CPU seconds... | |
320 | Rate b a | |
321 | b 1559428/s -- -62% | |
322 | a 4152037/s 166% -- | |
323 | ||
324 | ||
325 | while | |
326 | ||
327 | use Benchmark qw( timethese cmpthese ) ; | |
328 | $x = 3; | |
329 | $r = timethese( -5, { | |
330 | a => sub{$x*$x}, | |
331 | b => sub{$x**2}, | |
332 | } ); | |
333 | cmpthese $r; | |
334 | ||
335 | outputs something like this: | |
336 | ||
337 | Benchmark: running a, b, each for at least 5 CPU seconds... | |
338 | a: 10 wallclock secs ( 5.14 usr + 0.13 sys = 5.27 CPU) @ 3835055.60/s (n=20210743) | |
339 | b: 5 wallclock secs ( 5.41 usr + 0.00 sys = 5.41 CPU) @ 1574944.92/s (n=8520452) | |
340 | Rate b a | |
341 | b 1574945/s -- -59% | |
342 | a 3835056/s 144% -- | |
343 | ||
344 | ||
345 | =head1 INHERITANCE | |
346 | ||
347 | Benchmark inherits from no other class, except of course | |
348 | for Exporter. | |
349 | ||
350 | =head1 CAVEATS | |
351 | ||
352 | Comparing eval'd strings with code references will give you | |
353 | inaccurate results: a code reference will show a slightly slower | |
354 | execution time than the equivalent eval'd string. | |
355 | ||
356 | The real time timing is done using time(2) and | |
357 | the granularity is therefore only one second. | |
358 | ||
359 | Short tests may produce negative figures because perl | |
360 | can appear to take longer to execute the empty loop | |
361 | than a short test; try: | |
362 | ||
363 | timethis(100,'1'); | |
364 | ||
365 | The system time of the null loop might be slightly | |
366 | more than the system time of the loop with the actual | |
367 | code and therefore the difference might end up being E<lt> 0. | |
368 | ||
369 | =head1 SEE ALSO | |
370 | ||
371 | L<Devel::DProf> - a Perl code profiler | |
372 | ||
373 | =head1 AUTHORS | |
374 | ||
375 | Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>> | |
376 | ||
377 | =head1 MODIFICATION HISTORY | |
378 | ||
379 | September 8th, 1994; by Tim Bunce. | |
380 | ||
381 | March 28th, 1997; by Hugo van der Sanden: added support for code | |
382 | references and the already documented 'debug' method; revamped | |
383 | documentation. | |
384 | ||
385 | April 04-07th, 1997: by Jarkko Hietaniemi, added the run-for-some-time | |
386 | functionality. | |
387 | ||
388 | September, 1999; by Barrie Slaymaker: math fixes and accuracy and | |
389 | efficiency tweaks. Added cmpthese(). A result is now returned from | |
390 | timethese(). Exposed countit() (was runfor()). | |
391 | ||
392 | December, 2001; by Nicholas Clark: make timestr() recognise the style 'none' | |
393 | and return an empty string. If cmpthese is calling timethese, make it pass the | |
394 | style in. (so that 'none' will suppress output). Make sub new dump its | |
395 | debugging output to STDERR, to be consistent with everything else. | |
396 | All bugs found while writing a regression test. | |
397 | ||
398 | =cut | |
399 | ||
400 | # evaluate something in a clean lexical environment | |
401 | sub _doeval { eval shift } | |
402 | ||
403 | # | |
404 | # put any lexicals at file scope AFTER here | |
405 | # | |
406 | ||
407 | use Carp; | |
408 | use Exporter; | |
409 | @ISA=(Exporter); | |
410 | @EXPORT=qw(timeit timethis timethese timediff timestr); | |
411 | @EXPORT_OK=qw(timesum cmpthese countit | |
412 | clearcache clearallcache disablecache enablecache); | |
413 | %EXPORT_TAGS=( all => [ @EXPORT, @EXPORT_OK ] ) ; | |
414 | ||
415 | $VERSION = 1.04; | |
416 | ||
417 | &init; | |
418 | ||
419 | sub init { | |
420 | $debug = 0; | |
421 | $min_count = 4; | |
422 | $min_cpu = 0.4; | |
423 | $defaultfmt = '5.2f'; | |
424 | $defaultstyle = 'auto'; | |
425 | # The cache can cause a slight loss of sys time accuracy. If a | |
426 | # user does many tests (>10) with *very* large counts (>10000) | |
427 | # or works on a very slow machine the cache may be useful. | |
428 | &disablecache; | |
429 | &clearallcache; | |
430 | } | |
431 | ||
432 | sub debug { $debug = ($_[1] != 0); } | |
433 | ||
434 | # The cache needs two branches: 's' for strings and 'c' for code. The | |
435 | # emtpy loop is different in these two cases. | |
436 | sub clearcache { delete $cache{"$_[0]c"}; delete $cache{"$_[0]s"}; } | |
437 | sub clearallcache { %cache = (); } | |
438 | sub enablecache { $cache = 1; } | |
439 | sub disablecache { $cache = 0; } | |
440 | ||
441 | # --- Functions to process the 'time' data type | |
442 | ||
443 | sub new { my @t = (time, times, @_ == 2 ? $_[1] : 0); | |
444 | print STDERR "new=@t\n" if $debug; | |
445 | bless \@t; } | |
446 | ||
447 | sub cpu_p { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps ; } | |
448 | sub cpu_c { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $cu+$cs ; } | |
449 | sub cpu_a { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps+$cu+$cs ; } | |
450 | sub real { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $r ; } | |
451 | sub iters { $_[0]->[5] ; } | |
452 | ||
453 | sub timediff { | |
454 | my($a, $b) = @_; | |
455 | my @r; | |
456 | for (my $i=0; $i < @$a; ++$i) { | |
457 | push(@r, $a->[$i] - $b->[$i]); | |
458 | } | |
459 | bless \@r; | |
460 | } | |
461 | ||
462 | sub timesum { | |
463 | my($a, $b) = @_; | |
464 | my @r; | |
465 | for (my $i=0; $i < @$a; ++$i) { | |
466 | push(@r, $a->[$i] + $b->[$i]); | |
467 | } | |
468 | bless \@r; | |
469 | } | |
470 | ||
471 | sub timestr { | |
472 | my($tr, $style, $f) = @_; | |
473 | my @t = @$tr; | |
474 | warn "bad time value (@t)" unless @t==6; | |
475 | my($r, $pu, $ps, $cu, $cs, $n) = @t; | |
476 | my($pt, $ct, $tt) = ($tr->cpu_p, $tr->cpu_c, $tr->cpu_a); | |
477 | $f = $defaultfmt unless defined $f; | |
478 | # format a time in the required style, other formats may be added here | |
479 | $style ||= $defaultstyle; | |
480 | return '' if $style eq 'none'; | |
481 | $style = ($ct>0) ? 'all' : 'noc' if $style eq 'auto'; | |
482 | my $s = "@t $style"; # default for unknown style | |
483 | $s=sprintf("%2d wallclock secs (%$f usr %$f sys + %$f cusr %$f csys = %$f CPU)", | |
484 | $r,$pu,$ps,$cu,$cs,$tt) if $style eq 'all'; | |
485 | $s=sprintf("%2d wallclock secs (%$f usr + %$f sys = %$f CPU)", | |
486 | $r,$pu,$ps,$pt) if $style eq 'noc'; | |
487 | $s=sprintf("%2d wallclock secs (%$f cusr + %$f csys = %$f CPU)", | |
488 | $r,$cu,$cs,$ct) if $style eq 'nop'; | |
489 | $s .= sprintf(" @ %$f/s (n=$n)", $n / ( $pu + $ps )) if $n && $pu+$ps; | |
490 | $s; | |
491 | } | |
492 | ||
493 | sub timedebug { | |
494 | my($msg, $t) = @_; | |
495 | print STDERR "$msg",timestr($t),"\n" if $debug; | |
496 | } | |
497 | ||
498 | # --- Functions implementing low-level support for timing loops | |
499 | ||
500 | sub runloop { | |
501 | my($n, $c) = @_; | |
502 | ||
503 | $n+=0; # force numeric now, so garbage won't creep into the eval | |
504 | croak "negative loopcount $n" if $n<0; | |
505 | confess "Usage: runloop(number, [string | coderef])" unless defined $c; | |
506 | my($t0, $t1, $td); # before, after, difference | |
507 | ||
508 | # find package of caller so we can execute code there | |
509 | my($curpack) = caller(0); | |
510 | my($i, $pack)= 0; | |
511 | while (($pack) = caller(++$i)) { | |
512 | last if $pack ne $curpack; | |
513 | } | |
514 | ||
515 | my ($subcode, $subref); | |
516 | if (ref $c eq 'CODE') { | |
517 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; &\$c; } }"; | |
518 | $subref = eval $subcode; | |
519 | } | |
520 | else { | |
521 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; $c;} }"; | |
522 | $subref = _doeval($subcode); | |
523 | } | |
524 | croak "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@; | |
525 | print STDERR "runloop $n '$subcode'\n" if $debug; | |
526 | ||
527 | # Wait for the user timer to tick. This makes the error range more like | |
528 | # -0.01, +0. If we don't wait, then it's more like -0.01, +0.01. This | |
529 | # may not seem important, but it significantly reduces the chances of | |
530 | # getting a too low initial $n in the initial, 'find the minimum' loop | |
531 | # in &countit. This, in turn, can reduce the number of calls to | |
532 | # &runloop a lot, and thus reduce additive errors. | |
533 | my $tbase = Benchmark->new(0)->[1]; | |
534 | while ( ( $t0 = Benchmark->new(0) )->[1] == $tbase ) {} ; | |
535 | &$subref; | |
536 | $t1 = Benchmark->new($n); | |
537 | $td = &timediff($t1, $t0); | |
538 | timedebug("runloop:",$td); | |
539 | $td; | |
540 | } | |
541 | ||
542 | ||
543 | sub timeit { | |
544 | my($n, $code) = @_; | |
545 | my($wn, $wc, $wd); | |
546 | ||
547 | printf STDERR "timeit $n $code\n" if $debug; | |
548 | my $cache_key = $n . ( ref( $code ) ? 'c' : 's' ); | |
549 | if ($cache && exists $cache{$cache_key} ) { | |
550 | $wn = $cache{$cache_key}; | |
551 | } else { | |
552 | $wn = &runloop($n, ref( $code ) ? sub { } : '' ); | |
553 | # Can't let our baseline have any iterations, or they get subtracted | |
554 | # out of the result. | |
555 | $wn->[5] = 0; | |
556 | $cache{$cache_key} = $wn; | |
557 | } | |
558 | ||
559 | $wc = &runloop($n, $code); | |
560 | ||
561 | $wd = timediff($wc, $wn); | |
562 | timedebug("timeit: ",$wc); | |
563 | timedebug(" - ",$wn); | |
564 | timedebug(" = ",$wd); | |
565 | ||
566 | $wd; | |
567 | } | |
568 | ||
569 | ||
570 | my $default_for = 3; | |
571 | my $min_for = 0.1; | |
572 | ||
573 | ||
574 | sub countit { | |
575 | my ( $tmax, $code ) = @_; | |
576 | ||
577 | if ( not defined $tmax or $tmax == 0 ) { | |
578 | $tmax = $default_for; | |
579 | } elsif ( $tmax < 0 ) { | |
580 | $tmax = -$tmax; | |
581 | } | |
582 | ||
583 | die "countit($tmax, ...): timelimit cannot be less than $min_for.\n" | |
584 | if $tmax < $min_for; | |
585 | ||
586 | my ($n, $tc); | |
587 | ||
588 | # First find the minimum $n that gives a significant timing. | |
589 | for ($n = 1; ; $n *= 2 ) { | |
590 | my $td = timeit($n, $code); | |
591 | $tc = $td->[1] + $td->[2]; | |
592 | last if $tc > 0.1; | |
593 | } | |
594 | ||
595 | my $nmin = $n; | |
596 | ||
597 | # Get $n high enough that we can guess the final $n with some accuracy. | |
598 | my $tpra = 0.1 * $tmax; # Target/time practice. | |
599 | while ( $tc < $tpra ) { | |
600 | # The 5% fudge is to keep us from iterating again all | |
601 | # that often (this speeds overall responsiveness when $tmax is big | |
602 | # and we guess a little low). This does not noticably affect | |
603 | # accuracy since we're not couting these times. | |
604 | $n = int( $tpra * 1.05 * $n / $tc ); # Linear approximation. | |
605 | my $td = timeit($n, $code); | |
606 | my $new_tc = $td->[1] + $td->[2]; | |
607 | # Make sure we are making progress. | |
608 | $tc = $new_tc > 1.2 * $tc ? $new_tc : 1.2 * $tc; | |
609 | } | |
610 | ||
611 | # Now, do the 'for real' timing(s), repeating until we exceed | |
612 | # the max. | |
613 | my $ntot = 0; | |
614 | my $rtot = 0; | |
615 | my $utot = 0.0; | |
616 | my $stot = 0.0; | |
617 | my $cutot = 0.0; | |
618 | my $cstot = 0.0; | |
619 | my $ttot = 0.0; | |
620 | ||
621 | # The 5% fudge is because $n is often a few % low even for routines | |
622 | # with stable times and avoiding extra timeit()s is nice for | |
623 | # accuracy's sake. | |
624 | $n = int( $n * ( 1.05 * $tmax / $tc ) ); | |
625 | ||
626 | while () { | |
627 | my $td = timeit($n, $code); | |
628 | $ntot += $n; | |
629 | $rtot += $td->[0]; | |
630 | $utot += $td->[1]; | |
631 | $stot += $td->[2]; | |
632 | $cutot += $td->[3]; | |
633 | $cstot += $td->[4]; | |
634 | $ttot = $utot + $stot; | |
635 | last if $ttot >= $tmax; | |
636 | ||
637 | $ttot = 0.01 if $ttot < 0.01; | |
638 | my $r = $tmax / $ttot - 1; # Linear approximation. | |
639 | $n = int( $r * $ntot ); | |
640 | $n = $nmin if $n < $nmin; | |
641 | } | |
642 | ||
643 | return bless [ $rtot, $utot, $stot, $cutot, $cstot, $ntot ]; | |
644 | } | |
645 | ||
646 | # --- Functions implementing high-level time-then-print utilities | |
647 | ||
648 | sub n_to_for { | |
649 | my $n = shift; | |
650 | return $n == 0 ? $default_for : $n < 0 ? -$n : undef; | |
651 | } | |
652 | ||
653 | sub timethis{ | |
654 | my($n, $code, $title, $style) = @_; | |
655 | my($t, $for, $forn); | |
656 | ||
657 | if ( $n > 0 ) { | |
658 | croak "non-integer loopcount $n, stopped" if int($n)<$n; | |
659 | $t = timeit($n, $code); | |
660 | $title = "timethis $n" unless defined $title; | |
661 | } else { | |
662 | $fort = n_to_for( $n ); | |
663 | $t = countit( $fort, $code ); | |
664 | $title = "timethis for $fort" unless defined $title; | |
665 | $forn = $t->[-1]; | |
666 | } | |
667 | local $| = 1; | |
668 | $style = "" unless defined $style; | |
669 | printf("%10s: ", $title) unless $style eq 'none'; | |
670 | print timestr($t, $style, $defaultfmt),"\n" unless $style eq 'none'; | |
671 | ||
672 | $n = $forn if defined $forn; | |
673 | ||
674 | # A conservative warning to spot very silly tests. | |
675 | # Don't assume that your benchmark is ok simply because | |
676 | # you don't get this warning! | |
677 | print " (warning: too few iterations for a reliable count)\n" | |
678 | if $n < $min_count | |
679 | || ($t->real < 1 && $n < 1000) | |
680 | || $t->cpu_a < $min_cpu; | |
681 | $t; | |
682 | } | |
683 | ||
684 | sub timethese{ | |
685 | my($n, $alt, $style) = @_; | |
686 | die "usage: timethese(count, { 'Name1'=>'code1', ... }\n" | |
687 | unless ref $alt eq HASH; | |
688 | my @names = sort keys %$alt; | |
689 | $style = "" unless defined $style; | |
690 | print "Benchmark: " unless $style eq 'none'; | |
691 | if ( $n > 0 ) { | |
692 | croak "non-integer loopcount $n, stopped" if int($n)<$n; | |
693 | print "timing $n iterations of" unless $style eq 'none'; | |
694 | } else { | |
695 | print "running" unless $style eq 'none'; | |
696 | } | |
697 | print " ", join(', ',@names) unless $style eq 'none'; | |
698 | unless ( $n > 0 ) { | |
699 | my $for = n_to_for( $n ); | |
700 | print ", each" if $n > 1 && $style ne 'none'; | |
701 | print " for at least $for CPU seconds" unless $style eq 'none'; | |
702 | } | |
703 | print "...\n" unless $style eq 'none'; | |
704 | ||
705 | # we could save the results in an array and produce a summary here | |
706 | # sum, min, max, avg etc etc | |
707 | my %results; | |
708 | foreach my $name (@names) { | |
709 | $results{$name} = timethis ($n, $alt -> {$name}, $name, $style); | |
710 | } | |
711 | ||
712 | return \%results; | |
713 | } | |
714 | ||
715 | sub cmpthese{ | |
716 | my ($results, $style) = ref $_[0] ? @_ : ( timethese( @_[0,1,2] ), $_[2] ) ; | |
717 | ||
718 | $style = "" unless defined $style; | |
719 | ||
720 | # Flatten in to an array of arrays with the name as the first field | |
721 | my @vals = map{ [ $_, @{$results->{$_}} ] } keys %$results; | |
722 | ||
723 | for (@vals) { | |
724 | # The epsilon fudge here is to prevent div by 0. Since clock | |
725 | # resolutions are much larger, it's below the noise floor. | |
726 | my $rate = $_->[6] / ( $_->[2] + $_->[3] + 0.000000000000001 ); | |
727 | $_->[7] = $rate; | |
728 | } | |
729 | ||
730 | # Sort by rate | |
731 | @vals = sort { $a->[7] <=> $b->[7] } @vals; | |
732 | ||
733 | # If more than half of the rates are greater than one... | |
734 | my $display_as_rate = $vals[$#vals>>1]->[7] > 1; | |
735 | ||
736 | my @rows; | |
737 | my @col_widths; | |
738 | ||
739 | my @top_row = ( | |
740 | '', | |
741 | $display_as_rate ? 'Rate' : 's/iter', | |
742 | map { $_->[0] } @vals | |
743 | ); | |
744 | ||
745 | push @rows, \@top_row; | |
746 | @col_widths = map { length( $_ ) } @top_row; | |
747 | ||
748 | # Build the data rows | |
749 | # We leave the last column in even though it never has any data. Perhaps | |
750 | # it should go away. Also, perhaps a style for a single column of | |
751 | # percentages might be nice. | |
752 | for my $row_val ( @vals ) { | |
753 | my @row; | |
754 | ||
755 | # Column 0 = test name | |
756 | push @row, $row_val->[0]; | |
757 | $col_widths[0] = length( $row_val->[0] ) | |
758 | if length( $row_val->[0] ) > $col_widths[0]; | |
759 | ||
760 | # Column 1 = performance | |
761 | my $row_rate = $row_val->[7]; | |
762 | ||
763 | # We assume that we'll never get a 0 rate. | |
764 | my $a = $display_as_rate ? $row_rate : 1 / $row_rate; | |
765 | ||
766 | # Only give a few decimal places before switching to sci. notation, | |
767 | # since the results aren't usually that accurate anyway. | |
768 | my $format = | |
769 | $a >= 100 ? | |
770 | "%0.0f" : | |
771 | $a >= 10 ? | |
772 | "%0.1f" : | |
773 | $a >= 1 ? | |
774 | "%0.2f" : | |
775 | $a >= 0.1 ? | |
776 | "%0.3f" : | |
777 | "%0.2e"; | |
778 | ||
779 | $format .= "/s" | |
780 | if $display_as_rate; | |
781 | # Using $b here due to optimizing bug in _58 through _61 | |
782 | my $b = sprintf( $format, $a ); | |
783 | push @row, $b; | |
784 | $col_widths[1] = length( $b ) | |
785 | if length( $b ) > $col_widths[1]; | |
786 | ||
787 | # Columns 2..N = performance ratios | |
788 | my $skip_rest = 0; | |
789 | for ( my $col_num = 0 ; $col_num < @vals ; ++$col_num ) { | |
790 | my $col_val = $vals[$col_num]; | |
791 | my $out; | |
792 | if ( $skip_rest ) { | |
793 | $out = ''; | |
794 | } | |
795 | elsif ( $col_val->[0] eq $row_val->[0] ) { | |
796 | $out = "--"; | |
797 | # $skip_rest = 1; | |
798 | } | |
799 | else { | |
800 | my $col_rate = $col_val->[7]; | |
801 | $out = sprintf( "%.0f%%", 100*$row_rate/$col_rate - 100 ); | |
802 | } | |
803 | push @row, $out; | |
804 | $col_widths[$col_num+2] = length( $out ) | |
805 | if length( $out ) > $col_widths[$col_num+2]; | |
806 | ||
807 | # A little wierdness to set the first column width properly | |
808 | $col_widths[$col_num+2] = length( $col_val->[0] ) | |
809 | if length( $col_val->[0] ) > $col_widths[$col_num+2]; | |
810 | } | |
811 | push @rows, \@row; | |
812 | } | |
813 | ||
814 | return \@rows if $style eq "none"; | |
815 | ||
816 | # Equalize column widths in the chart as much as possible without | |
817 | # exceeding 80 characters. This does not use or affect cols 0 or 1. | |
818 | my @sorted_width_refs = | |
819 | sort { $$a <=> $$b } map { \$_ } @col_widths[2..$#col_widths]; | |
820 | my $max_width = ${$sorted_width_refs[-1]}; | |
821 | ||
822 | my $total = @col_widths - 1 ; | |
823 | for ( @col_widths ) { $total += $_ } | |
824 | ||
825 | STRETCHER: | |
826 | while ( $total < 80 ) { | |
827 | my $min_width = ${$sorted_width_refs[0]}; | |
828 | last | |
829 | if $min_width == $max_width; | |
830 | for ( @sorted_width_refs ) { | |
831 | last | |
832 | if $$_ > $min_width; | |
833 | ++$$_; | |
834 | ++$total; | |
835 | last STRETCHER | |
836 | if $total >= 80; | |
837 | } | |
838 | } | |
839 | ||
840 | # Dump the output | |
841 | my $format = join( ' ', map { "%${_}s" } @col_widths ) . "\n"; | |
842 | substr( $format, 1, 0 ) = '-'; | |
843 | for ( @rows ) { | |
844 | printf $format, @$_; | |
845 | } | |
846 | ||
847 | return \@rows ; | |
848 | } | |
849 | ||
850 | ||
851 | 1; |