The fastest way to pass arguments is not to copy them at all, and to access them inplace in @_. (This of course doesn't make readable code). The test case below illustrates this poorly for a simplified function.
Update: BrowserUk's answer demonstrates this better.
use Benchmark qw/cmpthese/;
sub s1 {my ($arg1, $arg2, $arg3) = @_; $arg+$arg2+$arg3 };
sub s2 { my $arg1 = shift; my $arg2 = shift; my $arg3 = shift; $arg1+$
+arg2+$arg3}
sub s3 {$_[0] + $_[1] + $_[2] }
cmpthese(200000, {
shift => ' { s2(1,2,3) }',
list => ' {s1(1,2,3)}',
none => ' {s3(1,2,3)}',
})
Benchmark: timing 200000 iterations of list, none, shift...
list: 4 wallclock secs ( 1.39 usr + 0.00 sys = 1.39 CPU) @ 14
+3884.89/s (n=200000)
none: 1 wallclock secs ( 0.70 usr + 0.01 sys = 0.71 CPU) @ 28
+1690.14/s (n=200000)
shift: 2 wallclock secs ( 1.46 usr + 0.03 sys = 1.49 CPU) @ 13
+4228.19/s (n=200000)
Rate shift list none
shift 134228/s -- -7% -52%
list 143885/s 7% -- -49%
none 281690/s 110% 96% --
--
integral, resident of freenode's #perl