use Benchmark;

timethese(-3, {
    aa => sub {
        $string = "blah+blah+blah";
        $string =~ tr/+/ /;
    },
    bb => sub {
        $string = "blah+blah+blah";
        $string =~ s/\+/ /g;
    },
    cc => sub {
        $string = "blah+blah+blah+blah+blah+blah";
        $string =~ tr/+/ /;
    },
    dd => sub {
        $string = "blah+blah+blah+blah+blah+blah";
        $string =~ s/\+/ /g;
    },
    ee => sub {
        $string = "blah";
        $string =~ tr/+/ /;
    },
    ff => sub {
        $string = "blah";
        $string =~ s/\+/ /g;
    },
});

print "\n";

timethese(-6, {
    aa => sub {
        $string = "blah+blah+blah";
        $string =~ tr/+/ /;
    },
    bb => sub {
        $string = "blah+blah+blah";
        $string =~ s/\+/ /g;
    },
    cc => sub {
        $string = "blah+blah+blah+blah+blah+blah";
        $string =~ tr/+/ /;
    },
    dd => sub {
        $string = "blah+blah+blah+blah+blah+blah";
        $string =~ s/\+/ /g;
    },
    ee => sub {
        $string = "blah";
        $string =~ tr/+/ /;
    },
    ff => sub {
        $string = "blah";
        $string =~ s/\+/ /g;
    },
});

##</code><code>##

Benchmark: running aa, bb, cc, dd, ee, ff, each for at least 3 CPU seconds...
        aa:  6 wallclock secs ( 2.91 usr +  0.10 sys =  3.01 CPU) @ 429021.93/s (n=1291356)
        bb:  8 wallclock secs ( 2.95 usr +  0.05 sys =  3.00 CPU) @ 208165.00/s (n=624495)
        cc:  8 wallclock secs ( 2.90 usr +  0.10 sys =  3.00 CPU) @ 404326.00/s (n=1212978)
        dd:  7 wallclock secs ( 2.88 usr +  0.12 sys =  3.00 CPU) @ 134898.33/s (n=404695)
        ee:  8 wallclock secs ( 3.21 usr +  0.02 sys =  3.23 CPU) @ 507243.96/s (n=1638398)
        ff:  6 wallclock secs ( 3.05 usr + -0.04 sys =  3.01 CPU) @ 603128.24/s (n=1815416)

Benchmark: running aa, bb, cc, dd, ee, ff, each for at least 6 CPU seconds...
        aa: 11 wallclock secs ( 5.87 usr +  0.14 sys =  6.01 CPU) @ 451358.24/s (n=2712663)
        bb: 11 wallclock secs ( 5.99 usr +  0.01 sys =  6.00 CPU) @ 222497.00/s (n=1334982)
        cc: 12 wallclock secs ( 6.12 usr +  0.01 sys =  6.13 CPU) @ 450148.29/s (n=2759409)
        dd: 11 wallclock secs ( 6.39 usr +  0.02 sys =  6.41 CPU) @ 149619.66/s (n=959062)
        ee: 12 wallclock secs ( 5.97 usr +  0.03 sys =  6.00 CPU) @ 520242.00/s (n=3121452)
        ff:  7 wallclock secs ( 6.01 usr +  0.00 sys =  6.01 CPU) @ 607347.25/s (n=3650157)