cache-compare.pl

-

#!/usr/local/bin/perl

# cache-compare.pl
#
# Duane Wessels, Dec 1995
#
# A simple perl script to compare how long it takes to fetch an object
# from a number of different caches.
#
# stdin is a list of URLs.  Set the @getfrom array to a list of caches
# to fetch each URL from.  Include 'SOURCE' in @getfrom to fetch from
# the source host also.  For each URL, print the byte count, elapsed
# time and average data rate.  At the end print out some averages.
#
# NOTE: uses the Perl function syscall() to implement gettimeofday(2).
# Assumes that gettimeofday is syscall #116 on the system
# (see /usr/include/sys/syscall.h).
#
# BUGS:
# Should probably cache the gethostbyname() calls.

@getfrom = ('SOURCE', 'localhost:3128', 'bo:3128');

require 'sys/socket.ph';
$gettimeofday = 1128;    	# cheating, should use require syscall.ph

while (<>) {
	chop ($url = $_);
	print "$url:\n";

	foreach $k (@getfrom) {
		printf "%30.30s:\t", $k;
		if ($k eq 'SOURCE') {
			($b_sec,$b_usec) = &gettimeofday;
			$n = &get_from_source($url);
			($e_sec,$e_usec) = &gettimeofday;
		} else {
			($host,$port) = split (':', $k);
			($b_sec,$b_usec) = &gettimeofday;
			$n = &get_from_cache($host,$port,$url);
			($e_sec,$e_usec) = &gettimeofday;
		}
		next unless ($n > 0);
		$d = ($e_sec - $b_sec) * 1000000 + ($e_usec - $b_usec);
		$d /= 1000000;
		$r = $n / $d;
		printf "%8.1f b/s (%7d bytes, %7.3f sec)\n",
			$r, $n, $d;
		$bps_sum{$k} += $r;
		$bps_n{$k}++;
		$bytes_sum{$k} += $n;
		$sec_sum{$k} += $d;
	}
}

print "AVERAGE b/s rates:\n";
	foreach $k (@getfrom) {
	printf "%30.30s:\t%8.1f b/s   (Alt: %8.1f b/s)\n",
		$k,
		$bps_sum{$k} / $bps_n{$k},
		$bytes_sum{$k} / $sec_sum{$k};
}

exit 0;

sub get_from_source {
	local($url) = @_;
	local($bytes) = 0;
	unless ($url =~ m!([a-z]+)://([^/]+)(.*)$!) {
		printf "get_from_source: bad URL\n";
		return 0;
	}
	$proto = $1;
	$host = $2;
	$url_path = $3;
	unless ($proto eq 'http') {
		printf "get_from_source: I only do HTTP\n";
		return 0;
	}
	$port = 80;
	if ($host =~ /([^:]+):(\d+)/) {
		$host = $1;
		$port = $2;
	}
	return 0 unless ($SOCK = &client_socket($host,$port));
	print $SOCK "GET $url_path HTTP/1.0\r\nAccept */*\r\n\r\n";
	$bytes += $n while (($n = read(SOCK,$_,4096)) > 0);
	close $SOCK;
	return $bytes;
}

sub get_from_cache {
	local($host,$port,$url) = @_;
	local($bytes) = 0;
	return 0 unless ($SOCK = &client_socket($host,$port));
	print $SOCK "GET $url HTTP/1.0\r\nAccept */*\r\n\r\n";
	$bytes += $n while (($n = read(SOCK,$_,4096)) > 0);
	close $SOCK;
	return $bytes;
}

sub client_socket {
        local ($host, $port) = @_;
        local ($sockaddr) = 'S n a4 x8';
        local ($name, $aliases, $proto) = getprotobyname('tcp');
        local ($connected) = 0;

        # Lookup addresses for remote hostname
        #
        local($w,$x,$y,$z,@thataddrs) = gethostbyname($host);
        unless (@thataddrs) {
        	printf "Unknown Host: $host\n";
		return ();
	}

        # bind local socket to INADDR_ANY
        #
        local ($thissock) = pack($sockaddr, &AF_INET, 0, "\0\0\0\0");
        unless (socket (SOCK, &AF_INET, &SOCK_STREAM, $proto)) {
        	printf  "socket: $!\n";
		return ();
	}
        unless (bind (SOCK, $thissock)) {
        	printf "bind: $!\n";
		return ();
	}

        # Try all addresses
        #
        foreach $thataddr (@thataddrs) {
                local ($that) = pack($sockaddr, &AF_INET, $port, $thataddr);
                if (connect (SOCK, $that)) {
                        $connected = 1;
                        last;
                }
        }
        unless ($connected) {
		printf "$host:$port: $!\n";
		return ();
	}

        # Set socket to flush-after-write and return it
        #
        select (SOCK); $| = 1;
        select (STDOUT);
        return (SOCK);
}

sub gettimeofday {
	$tvp="\0\0\0\0\0\0\0\0";
	syscall($gettimeofday, $tvp, $tz);
	return unpack('ll', $tvp);
}