I've either found a bug, a quirk, or I'm stupid, but I've been banging my head against this issue for two days now, and I finally at least isolated the cause.

I have a server that allows you to connect and make multiple queries on a single socket connection the main loop decides which function to call, the function prints data to the sock and once we return the main loop basically does print {$client} "__END__\n";

Apparently this is bad, and I've created a simple echoing client server pair which illustrate...

#!/idcom/bin/perl
use IO::Socket::INET;
use Time::HiRes qw( gettimeofday tv_interval );
use strict;

our $PORT = 9990;

if(fork) {
    my $s = IO::Socket::INET->new( LocalPort => $PORT, Listen => 5, Re
+use => 1 );
    
    my $c = $s->accept();
    
        while(<$c>) {
            print {$c} $_;
        }
}
else {
    sleep 1;
    my $s = IO::Socket::INET->new( PeerAddr => 'localhost:'.$PORT );
    for(1..5) {
        my $t0 = [gettimeofday];
        print {$s} "func=mbs_descriptive&type=&secid=313627KM2\n";
        print "".<$s>;
        print tv_interval( $t0, [gettimeofday] ),"\n";
    }   
}
[download]

When this runs all is great!

func=mbs_descriptive&type=&secid=313627KM2
0.000259
func=mbs_descriptive&type=&secid=313627KM2
5e-05
func=mbs_descriptive&type=&secid=313627KM2
4.3e-05
func=mbs_descriptive&type=&secid=313627KM2
4.2e-05
func=mbs_descriptive&type=&secid=313627KM2
4.2e-05
[download]

But if you change that print to the socket to be:

        print {$s} "func=mbs_descriptive&type=";
        print {$s} "&secid=313627KM2\n";
[download]

Then sadness and woe befall the code!

func=mbs_descriptive&type=&secid=313627KM2
0.000181
func=mbs_descriptive&type=&secid=313627KM2
0.040125
func=mbs_descriptive&type=&secid=313627KM2
0.04009
func=mbs_descriptive&type=&secid=313627KM2
0.039891
func=mbs_descriptive&type=&secid=313627KM2
0.040025
[download]

ARGH! The first call is fast, and every subsequent one has about .4s tacked on for fun, multiply that by 5000 and it starts to really add up. What am I missing here?