Commit | Line | Data |
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a0d0e21e LW |
1 | package Benchmark; |
2 | ||
f06db76b AD |
3 | =head1 NAME |
4 | ||
5 | Benchmark - benchmark running times of code | |
6 | ||
7 | timethis - run a chunk of code several times | |
8 | ||
9 | timethese - run several chunks of code several times | |
10 | ||
11 | timeit - run a chunk of code and see how long it goes | |
12 | ||
13 | =head1 SYNOPSIS | |
14 | ||
15 | timethis ($count, "code"); | |
16 | ||
523cc92b | 17 | # Use Perl code in strings... |
f06db76b AD |
18 | timethese($count, { |
19 | 'Name1' => '...code1...', | |
20 | 'Name2' => '...code2...', | |
21 | }); | |
22 | ||
523cc92b CS |
23 | # ... or use subroutine references. |
24 | timethese($count, { | |
25 | 'Name1' => sub { ...code1... }, | |
26 | 'Name2' => sub { ...code2... }, | |
27 | }); | |
28 | ||
f06db76b AD |
29 | $t = timeit($count, '...other code...') |
30 | print "$count loops of other code took:",timestr($t),"\n"; | |
31 | ||
32 | =head1 DESCRIPTION | |
33 | ||
34 | The Benchmark module encapsulates a number of routines to help you | |
35 | figure out how long it takes to execute some code. | |
36 | ||
37 | =head2 Methods | |
38 | ||
39 | =over 10 | |
40 | ||
41 | =item new | |
42 | ||
43 | Returns the current time. Example: | |
44 | ||
45 | use Benchmark; | |
46 | $t0 = new Benchmark; | |
47 | # ... your code here ... | |
48 | $t1 = new Benchmark; | |
49 | $td = timediff($t1, $t0); | |
a24a9dfe | 50 | print "the code took:",timestr($td),"\n"; |
f06db76b AD |
51 | |
52 | =item debug | |
53 | ||
54 | Enables or disable debugging by setting the C<$Benchmark::Debug> flag: | |
55 | ||
523cc92b | 56 | debug Benchmark 1; |
f06db76b | 57 | $t = timeit(10, ' 5 ** $Global '); |
523cc92b | 58 | debug Benchmark 0; |
f06db76b AD |
59 | |
60 | =back | |
61 | ||
62 | =head2 Standard Exports | |
63 | ||
523cc92b | 64 | The following routines will be exported into your namespace |
f06db76b AD |
65 | if you use the Benchmark module: |
66 | ||
67 | =over 10 | |
68 | ||
69 | =item timeit(COUNT, CODE) | |
70 | ||
523cc92b CS |
71 | Arguments: COUNT is the number of times to run the loop, and CODE is |
72 | the code to run. CODE may be either a code reference or a string to | |
73 | be eval'd; either way it will be run in the caller's package. | |
74 | ||
75 | Returns: a Benchmark object. | |
76 | ||
77 | =item timethis ( COUNT, CODE, [ TITLE, [ STYLE ]] ) | |
78 | ||
79 | Time COUNT iterations of CODE. CODE may be a string to eval or a | |
80 | code reference; either way the CODE will run in the caller's package. | |
81 | Results will be printed to STDOUT as TITLE followed by the times. | |
82 | TITLE defaults to "timethis COUNT" if none is provided. STYLE | |
83 | determines the format of the output, as described for timestr() below. | |
84 | ||
6ee623d5 GS |
85 | The COUNT can be zero or negative: this means the I<minimum number of |
86 | CPU seconds> to run. A zero signifies the default of 3 seconds. For | |
87 | example to run at least for 10 seconds: | |
88 | ||
89 | timethis(-10, $code) | |
90 | ||
91 | or to run two pieces of code tests for at least 3 seconds: | |
92 | ||
93 | timethese(0, { test1 => '...', test2 => '...'}) | |
94 | ||
95 | CPU seconds is, in UNIX terms, the user time plus the system time of | |
96 | the process itself, as opposed to the real (wallclock) time and the | |
97 | time spent by the child processes. Less than 0.1 seconds is not | |
98 | accepted (-0.01 as the count, for example, will cause a fatal runtime | |
99 | exception). | |
100 | ||
101 | Note that the CPU seconds is the B<minimum> time: CPU scheduling and | |
102 | other operating system factors may complicate the attempt so that a | |
103 | little bit more time is spent. The benchmark output will, however, | |
104 | also tell the number of C<$code> runs/second, which should be a more | |
105 | interesting number than the actually spent seconds. | |
106 | ||
107 | Returns a Benchmark object. | |
108 | ||
523cc92b | 109 | =item timethese ( COUNT, CODEHASHREF, [ STYLE ] ) |
f06db76b | 110 | |
523cc92b CS |
111 | The CODEHASHREF is a reference to a hash containing names as keys |
112 | and either a string to eval or a code reference for each value. | |
113 | For each (KEY, VALUE) pair in the CODEHASHREF, this routine will | |
114 | call | |
f06db76b | 115 | |
523cc92b | 116 | timethis(COUNT, VALUE, KEY, STYLE) |
f06db76b | 117 | |
1d2dff63 GS |
118 | The routines are called in string comparison order of KEY. |
119 | ||
120 | The COUNT can be zero or negative, see timethis(). | |
6ee623d5 | 121 | |
523cc92b | 122 | =item timediff ( T1, T2 ) |
f06db76b | 123 | |
523cc92b CS |
124 | Returns the difference between two Benchmark times as a Benchmark |
125 | object suitable for passing to timestr(). | |
f06db76b | 126 | |
705cc255 TB |
127 | =item timesum ( T1, T2 ) |
128 | ||
129 | Returns the sum of two Benchmark times as a Benchmark object suitable | |
130 | for passing to timestr(). | |
131 | ||
6ee623d5 | 132 | =item timestr ( TIMEDIFF, [ STYLE, [ FORMAT ] ] ) |
f06db76b | 133 | |
523cc92b CS |
134 | Returns a string that formats the times in the TIMEDIFF object in |
135 | the requested STYLE. TIMEDIFF is expected to be a Benchmark object | |
136 | similar to that returned by timediff(). | |
137 | ||
138 | STYLE can be any of 'all', 'noc', 'nop' or 'auto'. 'all' shows each | |
139 | of the 5 times available ('wallclock' time, user time, system time, | |
140 | user time of children, and system time of children). 'noc' shows all | |
141 | except the two children times. 'nop' shows only wallclock and the | |
142 | two children times. 'auto' (the default) will act as 'all' unless | |
143 | the children times are both zero, in which case it acts as 'noc'. | |
144 | ||
145 | FORMAT is the L<printf(3)>-style format specifier (without the | |
146 | leading '%') to use to print the times. It defaults to '5.2f'. | |
f06db76b AD |
147 | |
148 | =back | |
149 | ||
150 | =head2 Optional Exports | |
151 | ||
152 | The following routines will be exported into your namespace | |
153 | if you specifically ask that they be imported: | |
154 | ||
155 | =over 10 | |
156 | ||
523cc92b CS |
157 | =item clearcache ( COUNT ) |
158 | ||
159 | Clear the cached time for COUNT rounds of the null loop. | |
160 | ||
161 | =item clearallcache ( ) | |
f06db76b | 162 | |
523cc92b | 163 | Clear all cached times. |
f06db76b | 164 | |
523cc92b | 165 | =item disablecache ( ) |
f06db76b | 166 | |
523cc92b CS |
167 | Disable caching of timings for the null loop. This will force Benchmark |
168 | to recalculate these timings for each new piece of code timed. | |
169 | ||
170 | =item enablecache ( ) | |
171 | ||
172 | Enable caching of timings for the null loop. The time taken for COUNT | |
173 | rounds of the null loop will be calculated only once for each | |
174 | different COUNT used. | |
f06db76b AD |
175 | |
176 | =back | |
177 | ||
178 | =head1 NOTES | |
179 | ||
180 | The data is stored as a list of values from the time and times | |
523cc92b | 181 | functions: |
f06db76b AD |
182 | |
183 | ($real, $user, $system, $children_user, $children_system) | |
184 | ||
185 | in seconds for the whole loop (not divided by the number of rounds). | |
186 | ||
187 | The timing is done using time(3) and times(3). | |
188 | ||
189 | Code is executed in the caller's package. | |
190 | ||
f06db76b AD |
191 | The time of the null loop (a loop with the same |
192 | number of rounds but empty loop body) is subtracted | |
193 | from the time of the real loop. | |
194 | ||
195 | The null loop times are cached, the key being the | |
196 | number of rounds. The caching can be controlled using | |
197 | calls like these: | |
198 | ||
523cc92b | 199 | clearcache($key); |
f06db76b AD |
200 | clearallcache(); |
201 | ||
523cc92b | 202 | disablecache(); |
f06db76b AD |
203 | enablecache(); |
204 | ||
205 | =head1 INHERITANCE | |
206 | ||
207 | Benchmark inherits from no other class, except of course | |
208 | for Exporter. | |
209 | ||
210 | =head1 CAVEATS | |
211 | ||
80eab818 CS |
212 | Comparing eval'd strings with code references will give you |
213 | inaccurate results: a code reference will show a slower | |
214 | execution time than the equivalent eval'd string. | |
215 | ||
f06db76b AD |
216 | The real time timing is done using time(2) and |
217 | the granularity is therefore only one second. | |
218 | ||
219 | Short tests may produce negative figures because perl | |
523cc92b CS |
220 | can appear to take longer to execute the empty loop |
221 | than a short test; try: | |
f06db76b AD |
222 | |
223 | timethis(100,'1'); | |
224 | ||
225 | The system time of the null loop might be slightly | |
226 | more than the system time of the loop with the actual | |
a24a9dfe | 227 | code and therefore the difference might end up being E<lt> 0. |
f06db76b | 228 | |
f06db76b AD |
229 | =head1 AUTHORS |
230 | ||
5aabfad6 | 231 | Jarkko Hietaniemi <F<jhi@iki.fi>>, Tim Bunce <F<Tim.Bunce@ig.co.uk>> |
f06db76b AD |
232 | |
233 | =head1 MODIFICATION HISTORY | |
234 | ||
235 | September 8th, 1994; by Tim Bunce. | |
236 | ||
523cc92b CS |
237 | March 28th, 1997; by Hugo van der Sanden: added support for code |
238 | references and the already documented 'debug' method; revamped | |
239 | documentation. | |
f06db76b | 240 | |
6ee623d5 GS |
241 | April 04-07th, 1997: by Jarkko Hietaniemi, added the run-for-some-time |
242 | functionality. | |
243 | ||
523cc92b | 244 | =cut |
a0d0e21e | 245 | |
3f943bd9 GS |
246 | # evaluate something in a clean lexical environment |
247 | sub _doeval { eval shift } | |
248 | ||
249 | # | |
250 | # put any lexicals at file scope AFTER here | |
251 | # | |
252 | ||
4aa0a1f7 | 253 | use Carp; |
a0d0e21e LW |
254 | use Exporter; |
255 | @ISA=(Exporter); | |
256 | @EXPORT=qw(timeit timethis timethese timediff timestr); | |
257 | @EXPORT_OK=qw(clearcache clearallcache disablecache enablecache); | |
258 | ||
259 | &init; | |
260 | ||
261 | sub init { | |
262 | $debug = 0; | |
263 | $min_count = 4; | |
264 | $min_cpu = 0.4; | |
265 | $defaultfmt = '5.2f'; | |
266 | $defaultstyle = 'auto'; | |
267 | # The cache can cause a slight loss of sys time accuracy. If a | |
268 | # user does many tests (>10) with *very* large counts (>10000) | |
269 | # or works on a very slow machine the cache may be useful. | |
270 | &disablecache; | |
271 | &clearallcache; | |
272 | } | |
273 | ||
523cc92b CS |
274 | sub debug { $debug = ($_[1] != 0); } |
275 | ||
a0d0e21e LW |
276 | sub clearcache { delete $cache{$_[0]}; } |
277 | sub clearallcache { %cache = (); } | |
278 | sub enablecache { $cache = 1; } | |
279 | sub disablecache { $cache = 0; } | |
280 | ||
a0d0e21e LW |
281 | # --- Functions to process the 'time' data type |
282 | ||
6ee623d5 GS |
283 | sub new { my @t = (time, times, @_ == 2 ? $_[1] : 0); |
284 | print "new=@t\n" if $debug; | |
285 | bless \@t; } | |
a0d0e21e LW |
286 | |
287 | sub cpu_p { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps ; } | |
288 | sub cpu_c { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $cu+$cs ; } | |
289 | sub cpu_a { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $pu+$ps+$cu+$cs ; } | |
290 | sub real { my($r,$pu,$ps,$cu,$cs) = @{$_[0]}; $r ; } | |
291 | ||
523cc92b | 292 | sub timediff { |
a0d0e21e | 293 | my($a, $b) = @_; |
523cc92b | 294 | my @r; |
3f943bd9 | 295 | for (my $i=0; $i < @$a; ++$i) { |
a0d0e21e LW |
296 | push(@r, $a->[$i] - $b->[$i]); |
297 | } | |
298 | bless \@r; | |
299 | } | |
300 | ||
705cc255 TB |
301 | sub timesum { |
302 | my($a, $b) = @_; | |
303 | my @r; | |
304 | for (my $i=0; $i < @$a; ++$i) { | |
305 | push(@r, $a->[$i] + $b->[$i]); | |
306 | } | |
307 | bless \@r; | |
308 | } | |
309 | ||
523cc92b | 310 | sub timestr { |
a0d0e21e | 311 | my($tr, $style, $f) = @_; |
523cc92b | 312 | my @t = @$tr; |
6ee623d5 GS |
313 | warn "bad time value (@t)" unless @t==6; |
314 | my($r, $pu, $ps, $cu, $cs, $n) = @t; | |
a0d0e21e | 315 | my($pt, $ct, $t) = ($tr->cpu_p, $tr->cpu_c, $tr->cpu_a); |
523cc92b | 316 | $f = $defaultfmt unless defined $f; |
a0d0e21e | 317 | # format a time in the required style, other formats may be added here |
80eab818 | 318 | $style ||= $defaultstyle; |
523cc92b CS |
319 | $style = ($ct>0) ? 'all' : 'noc' if $style eq 'auto'; |
320 | my $s = "@t $style"; # default for unknown style | |
7be077a2 | 321 | $s=sprintf("%2d wallclock secs (%$f usr %$f sys + %$f cusr %$f csys = %$f CPU)", |
523cc92b | 322 | @t,$t) if $style eq 'all'; |
7be077a2 GS |
323 | $s=sprintf("%2d wallclock secs (%$f usr + %$f sys = %$f CPU)", |
324 | $r,$pu,$ps,$pt) if $style eq 'noc'; | |
325 | $s=sprintf("%2d wallclock secs (%$f cusr + %$f csys = %$f CPU)", | |
326 | $r,$cu,$cs,$ct) if $style eq 'nop'; | |
6ee623d5 | 327 | $s .= sprintf(" @ %$f/s (n=$n)", $n / ( $pu + $ps )) if $n; |
a0d0e21e LW |
328 | $s; |
329 | } | |
523cc92b CS |
330 | |
331 | sub timedebug { | |
a0d0e21e | 332 | my($msg, $t) = @_; |
523cc92b | 333 | print STDERR "$msg",timestr($t),"\n" if $debug; |
a0d0e21e LW |
334 | } |
335 | ||
a0d0e21e LW |
336 | # --- Functions implementing low-level support for timing loops |
337 | ||
338 | sub runloop { | |
339 | my($n, $c) = @_; | |
4aa0a1f7 AD |
340 | |
341 | $n+=0; # force numeric now, so garbage won't creep into the eval | |
523cc92b CS |
342 | croak "negative loopcount $n" if $n<0; |
343 | confess "Usage: runloop(number, [string | coderef])" unless defined $c; | |
a0d0e21e LW |
344 | my($t0, $t1, $td); # before, after, difference |
345 | ||
346 | # find package of caller so we can execute code there | |
523cc92b CS |
347 | my($curpack) = caller(0); |
348 | my($i, $pack)= 0; | |
a0d0e21e LW |
349 | while (($pack) = caller(++$i)) { |
350 | last if $pack ne $curpack; | |
351 | } | |
352 | ||
3f943bd9 GS |
353 | my ($subcode, $subref); |
354 | if (ref $c eq 'CODE') { | |
355 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; &\$c; } }"; | |
356 | $subref = eval $subcode; | |
357 | } | |
358 | else { | |
359 | $subcode = "sub { for (1 .. $n) { local \$_; package $pack; $c;} }"; | |
360 | $subref = _doeval($subcode); | |
361 | } | |
4aa0a1f7 | 362 | croak "runloop unable to compile '$c': $@\ncode: $subcode\n" if $@; |
523cc92b | 363 | print STDERR "runloop $n '$subcode'\n" if $debug; |
a0d0e21e | 364 | |
6ee623d5 | 365 | $t0 = Benchmark->new(0); |
a0d0e21e | 366 | &$subref; |
6ee623d5 | 367 | $t1 = Benchmark->new($n); |
a0d0e21e LW |
368 | $td = &timediff($t1, $t0); |
369 | ||
370 | timedebug("runloop:",$td); | |
371 | $td; | |
372 | } | |
373 | ||
374 | ||
375 | sub timeit { | |
376 | my($n, $code) = @_; | |
377 | my($wn, $wc, $wd); | |
378 | ||
379 | printf STDERR "timeit $n $code\n" if $debug; | |
380 | ||
523cc92b | 381 | if ($cache && exists $cache{$n}) { |
a0d0e21e | 382 | $wn = $cache{$n}; |
523cc92b | 383 | } else { |
a0d0e21e LW |
384 | $wn = &runloop($n, ''); |
385 | $cache{$n} = $wn; | |
386 | } | |
387 | ||
388 | $wc = &runloop($n, $code); | |
389 | ||
390 | $wd = timediff($wc, $wn); | |
391 | ||
392 | timedebug("timeit: ",$wc); | |
393 | timedebug(" - ",$wn); | |
394 | timedebug(" = ",$wd); | |
395 | ||
396 | $wd; | |
397 | } | |
398 | ||
6ee623d5 GS |
399 | |
400 | my $default_for = 3; | |
401 | my $min_for = 0.1; | |
402 | ||
403 | sub runfor { | |
404 | my ($code, $tmax) = @_; | |
405 | ||
406 | if ( not defined $tmax or $tmax == 0 ) { | |
407 | $tmax = $default_for; | |
408 | } elsif ( $tmax < 0 ) { | |
409 | $tmax = -$tmax; | |
410 | } | |
411 | ||
412 | die "runfor(..., $tmax): timelimit cannot be less than $min_for.\n" | |
413 | if $tmax < $min_for; | |
414 | ||
415 | my ($n, $td, $tc, $ntot, $rtot, $utot, $stot, $cutot, $cstot ); | |
416 | ||
417 | # First find the minimum $n that gives a non-zero timing. | |
418 | ||
419 | my $nmin; | |
420 | ||
421 | for ($n = 1, $tc = 0; $tc <= 0; $n *= 2 ) { | |
422 | $td = timeit($n, $code); | |
423 | $tc = $td->[1] + $td->[2]; | |
424 | } | |
425 | ||
426 | $nmin = $n; | |
427 | ||
428 | my $ttot = 0; | |
429 | my $tpra = 0.05 * $tmax; # Target/time practice. | |
430 | ||
431 | # Double $n until we have think we have practiced enough. | |
432 | for ( $n = 1; $ttot < $tpra; $n *= 2 ) { | |
433 | $td = timeit($n, $code); | |
434 | $tc = $td->cpu_p; | |
435 | $ntot += $n; | |
436 | $rtot += $td->[0]; | |
437 | $utot += $td->[1]; | |
438 | $stot += $td->[2]; | |
439 | $ttot = $utot + $stot; | |
440 | $cutot += $td->[3]; | |
441 | $cstot += $td->[4]; | |
442 | } | |
443 | ||
444 | my $r; | |
445 | ||
446 | # Then iterate towards the $tmax. | |
447 | while ( $ttot < $tmax ) { | |
448 | $r = $tmax / $ttot - 1; # Linear approximation. | |
449 | $n = int( $r * $n ); | |
450 | $n = $nmin if $n < $nmin; | |
451 | $td = timeit($n, $code); | |
452 | $ntot += $n; | |
453 | $rtot += $td->[0]; | |
454 | $utot += $td->[1]; | |
455 | $stot += $td->[2]; | |
456 | $ttot = $utot + $stot; | |
457 | $cutot += $td->[3]; | |
458 | $cstot += $td->[4]; | |
459 | } | |
460 | ||
461 | return bless [ $rtot, $utot, $stot, $cutot, $cstot, $ntot ]; | |
462 | } | |
463 | ||
a0d0e21e LW |
464 | # --- Functions implementing high-level time-then-print utilities |
465 | ||
6ee623d5 GS |
466 | sub n_to_for { |
467 | my $n = shift; | |
468 | return $n == 0 ? $default_for : $n < 0 ? -$n : undef; | |
469 | } | |
470 | ||
a0d0e21e LW |
471 | sub timethis{ |
472 | my($n, $code, $title, $style) = @_; | |
6ee623d5 GS |
473 | my($t, $for, $forn); |
474 | ||
475 | if ( $n > 0 ) { | |
476 | croak "non-integer loopcount $n, stopped" if int($n)<$n; | |
477 | $t = timeit($n, $code); | |
478 | $title = "timethis $n" unless defined $title; | |
479 | } else { | |
480 | $fort = n_to_for( $n ); | |
481 | $t = runfor($code, $fort); | |
482 | $title = "timethis for $fort" unless defined $title; | |
483 | $forn = $t->[-1]; | |
484 | } | |
523cc92b | 485 | local $| = 1; |
523cc92b | 486 | $style = "" unless defined $style; |
a0d0e21e | 487 | printf("%10s: ", $title); |
6ee623d5 GS |
488 | print timestr($t, $style, $defaultfmt),"\n"; |
489 | ||
490 | $n = $forn if defined $forn; | |
523cc92b | 491 | |
a0d0e21e LW |
492 | # A conservative warning to spot very silly tests. |
493 | # Don't assume that your benchmark is ok simply because | |
494 | # you don't get this warning! | |
495 | print " (warning: too few iterations for a reliable count)\n" | |
523cc92b | 496 | if $n < $min_count |
a0d0e21e | 497 | || ($t->real < 1 && $n < 1000) |
523cc92b | 498 | || $t->cpu_a < $min_cpu; |
a0d0e21e LW |
499 | $t; |
500 | } | |
501 | ||
a0d0e21e LW |
502 | sub timethese{ |
503 | my($n, $alt, $style) = @_; | |
504 | die "usage: timethese(count, { 'Name1'=>'code1', ... }\n" | |
505 | unless ref $alt eq HASH; | |
523cc92b CS |
506 | my @names = sort keys %$alt; |
507 | $style = "" unless defined $style; | |
6ee623d5 GS |
508 | print "Benchmark: "; |
509 | if ( $n > 0 ) { | |
510 | croak "non-integer loopcount $n, stopped" if int($n)<$n; | |
511 | print "timing $n iterations of"; | |
512 | } else { | |
513 | print "running"; | |
514 | } | |
515 | print " ", join(', ',@names); | |
516 | unless ( $n > 0 ) { | |
517 | my $for = n_to_for( $n ); | |
518 | print ", each for at least $for CPU seconds"; | |
519 | } | |
520 | print "...\n"; | |
523cc92b CS |
521 | |
522 | # we could save the results in an array and produce a summary here | |
a0d0e21e | 523 | # sum, min, max, avg etc etc |
4dbb2df9 A |
524 | foreach my $name (@names) { |
525 | timethis ($n, $alt -> {$name}, $name, $style); | |
526 | } | |
a0d0e21e LW |
527 | } |
528 | ||
a0d0e21e | 529 | 1; |