In benchmarking some code I've come across something I did not expect:
slice:
use strict;
use warnings;
my @k=qw(1 2 3 4 5 6);
my %n;@[EMAIL PROTECTED] = @k;
print "hi" if exists $n{1};
print "hi" if exists $n{3};
print "hi" if exists $n{5};
print "hi" if exists $n{7};
print "hi" if exists $n{9};
print "hi" if exists $n{11};grep: use strict; use warnings; my @k=qw(1 2 3 4 5 6); print "hi" if grep /^1$/, @k; print "hi" if grep /^3$/, @k; print "hi" if grep /^5$/, @k; print "hi" if grep /^7$/, @k; print "hi" if grep /^9$/, @k; print "hi" if grep /^11$/, @k;
Benchmark: timing 5000000 iterations of grep, slice...
grep: 3.65945 wallclock secs ( 2.33 usr + 0.04 sys = 2.37 CPU) @ 2109704.64/s (n=5000000)
slice: 2.37966 wallclock secs ( 2.52 usr + -0.01 sys = 2.51 CPU) @ 1992031.87/s (n=5000000)
Rate slice grep
slice 1992032/s -- -6%
grep 2109705/s 6% --
I would've thought the "slice and then use exists" would have been faster then "greping the entire array each time and using regexes" when you check it. but its consistently faster by an average 6-10%
Any ideas why that might be?
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