为什么这两个RegEx基准测试差异如此之大？
发布时间：2020-12-16 06:16:44 所属栏目：大数据 来源：网络整理
导读：为什么这两个RegEx基准测试差异如此之大？ 他们使用相同的RegEx,一个就地,一个通过qr存储// 结果： Rate rege1.FIND_AT_END rege2.FIND_AT_ENDrege1.FIND_AT_END 661157/s -- -85%rege2.FIND_AT_END 4384042/s 563% -- Rate rege1.NOFIND rege2.NOFINDrege1.
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为什么这两个RegEx基准测试差异如此之大？
他们使用相同的RegEx,一个就地,一个通过qr存储// 结果：
Rate rege1.FIND_AT_END rege2.FIND_AT_END
rege1.FIND_AT_END 661157/s -- -85%
rege2.FIND_AT_END 4384042/s 563% --
Rate rege1.NOFIND rege2.NOFIND
rege1.NOFIND 678702/s -- -87%
rege2.NOFIND 5117707/s 654% --
Rate rege1.FIND_AT_START rege2.FIND_AT_START
rege1.FIND_AT_START 657765/s -- -85%
rege2.FIND_AT_START 4268032/s 549% --
# Benchmark
use Benchmark qw(:all);
my $count = 10000000;
my $re = qr/abc/o;
my %tests = (
"NOFIND " => "cvxcvidgds.sdfpkisd[s","FIND_AT_END " => "cvxcvidgds.sdfpabcd[s","FIND_AT_START " => "abccvidgds.sdfpkisd[s"
);
foreach my $type (keys %tests) {
my $str = $tests{$type};
cmpthese($count,{
"rege1.$type" => sub { my $idx = ($str =~ $re); },"rege2.$type" => sub { my $idx = ($str =~ /abc/o); }
});
}
解决方法
您正在处理本质上非常快的操作,因此您需要再运行一些测试来缩小速度的范围.我还将基准模型从外部(让cmpthese做到)切换到内部(for loop)速度放大.这可以最大限度地减少子程序调用的开销以及cmpthese必须执行的任何工作.最后,测试以确定差异是否与量级成比例是重要的(在这种情况下它不是).
use Benchmark 'cmpthese';
my $re = qr/abc/o;
my %tests = (
'fail ' => 'cvxcvidgds.sdfpkisd[s','end ' => 'cvxcvidgds.sdfpabcd[s','start' => 'abccvidgds.sdfpkisd[s',);
for my $mag (map 10**$_,1 .. 5) {
say "n$mag:";
for my $type (keys %tests) {
my $str = $tests{$type};
cmpthese -1,{
'$re '.$type => sub {my $i; $i = ($str =~ $re ) for 0 .. $mag},'/abc/o '.$type => sub {my $i; $i = ($str =~ /abc/o) for 0 .. $mag},'/$re/ '.$type => sub {my $i; $i = ($str =~ /$re/ ) for 0 .. $mag},'/$re/o '.$type => sub {my $i; $i = ($str =~ /$re/o) for 0 .. $mag},}
}
}
10:
Rate $re fail /$re/ fail /$re/o fail /abc/o fail
$re fail 106390/s -- -8% -72% -74%
/$re/ fail 115814/s 9% -- -70% -71%
/$re/o fail 384635/s 262% 232% -- -5%
/abc/o fail 403944/s 280% 249% 5% --
Rate $re end /$re/ end /$re/o end /abc/o end
$re end 105527/s -- -5% -71% -72%
/$re/ end 110902/s 5% -- -69% -71%
/$re/o end 362544/s 244% 227% -- -5%
/abc/o end 382242/s 262% 245% 5% --
Rate $re start /$re/ start /$re/o start /abc/o start
$re start 111002/s -- -3% -72% -73%
/$re/ start 114094/s 3% -- -71% -73%
/$re/o start 390693/s 252% 242% -- -6%
/abc/o start 417123/s 276% 266% 7% --
100:
Rate /$re/ fail $re fail /$re/o fail /abc/o fail
/$re/ fail 12329/s -- -4% -77% -79%
$re fail 12789/s 4% -- -76% -78%
/$re/o fail 53194/s 331% 316% -- -9%
/abc/o fail 58377/s 373% 356% 10% --
Rate $re end /$re/ end /$re/o end /abc/o end
$re end 12440/s -- -1% -75% -77%
/$re/ end 12623/s 1% -- -75% -77%
/$re/o end 50127/s 303% 297% -- -7%
/abc/o end 53941/s 334% 327% 8% --
Rate $re start /$re/ start /$re/o start /abc/o start
$re start 12810/s -- -3% -76% -78%
/$re/ start 13190/s 3% -- -75% -77%
/$re/o start 52512/s 310% 298% -- -8%
/abc/o start 57045/s 345% 332% 9% --
1000:
Rate $re fail /$re/ fail /$re/o fail /abc/o fail
$re fail 1248/s -- -8% -76% -80%
/$re/ fail 1354/s 9% -- -74% -79%
/$re/o fail 5284/s 323% 290% -- -16%
/abc/o fail 6311/s 406% 366% 19% --
Rate $re end /$re/ end /$re/o end /abc/o end
$re end 1316/s -- -1% -74% -77%
/$re/ end 1330/s 1% -- -74% -77%
/$re/o end 5119/s 289% 285% -- -11%
/abc/o end 5757/s 338% 333% 12% --
Rate /$re/ start $re start /$re/o start /abc/o start
/$re/ start 1283/s -- -1% -75% -81%
$re start 1302/s 1% -- -75% -80%
/$re/o start 5119/s 299% 293% -- -22%
/abc/o start 6595/s 414% 406% 29% --
10000:
Rate /$re/ fail $re fail /$re/o fail /abc/o fail
/$re/ fail 130/s -- -6% -76% -80%
$re fail 139/s 7% -- -74% -79%
/$re/o fail 543/s 317% 291% -- -17%
/abc/o fail 651/s 400% 368% 20% --
Rate /$re/ end $re end /$re/o end /abc/o end
/$re/ end 128/s -- -3% -76% -79%
$re end 132/s 3% -- -76% -78%
/$re/o end 541/s 322% 311% -- -10%
/abc/o end 598/s 366% 354% 11% --
Rate /$re/ start $re start /$re/o start /abc/o start
/$re/ start 132/s -- -1% -77% -80%
$re start 133/s 1% -- -76% -79%
/$re/o start 566/s 330% 325% -- -13%
/abc/o start 650/s 394% 388% 15% --
100000:
Rate /$re/ fail $re fail /$re/o fail /abc/o fail
/$re/ fail 13.2/s -- -8% -76% -78%
$re fail 14.2/s 8% -- -74% -76%
/$re/o fail 55.9/s 325% 292% -- -8%
/abc/o fail 60.5/s 360% 324% 8% --
Rate /$re/ end $re end /$re/o end /abc/o end
/$re/ end 12.8/s -- -3% -75% -79%
$re end 13.2/s 3% -- -75% -78%
/$re/o end 52.3/s 308% 297% -- -12%
/abc/o end 59.7/s 365% 353% 14% --
Rate $re start /$re/ start /$re/o start /abc/o start
$re start 13.4/s -- -2% -77% -78%
/$re/ start 13.6/s 2% -- -77% -78%
/$re/o start 58.2/s 334% 328% -- -6%
/abc/o start 62.2/s 364% 357% 7% --
您可以很容易地看到测试分为两类,一类是源中的/…/,另一类是没有.由于这是一个合成差异,它为您提供线索,可能是编译器正在优化的情况(或者允许运行时以某种方式缓存). (在完成一次变量后删除对变量的检查,简化堆栈,很难说不看源). 结果可能还取决于所使用的perl的版本.上述测试在v5.10.1上运行 （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |