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#! @PATH_PERL@ -w
die "perl5 needed\n" unless ($] > 5);
use Getopt::Std;
use vars qw($opt_n);
getopts('d:nt:');
#chop($ncpu = `sysctl -n hw.ncpu`);
#die "Found $ncpu CPUs; can only be run on systems with 1 CPU.\n" if ($ncpu > 1);
$driftfile = "/etc/ntp.drift";
$driftfile = $opt_d if defined($opt_d);
chop($timer = `sysctl -n kern.timecounter.hardware 2> /dev/null`);
$timer =~ tr/\U/\L/;
if ($timer eq '') {
open(DM, "/var/run/dmesg.boot");
while(<DM>) {
# Timecounter "i8254" frequency 1193182 Hz
if (/^Timecounter "(\w+)"\s+/) {
$timer = $1;
last;
}
}
close(DM);
}
$opt_t = $timer if !defined($opt_t);
if ($timer ne '') { # $timer found...
if ($opt_t ne '') { # - and $opt_t found
if ($timer ne $opt_t) { # - - and they differ
warn "You specified a $opt_t timer but I detected a $timer timer.\n";
usage();
exit 1;
} else { # - - and they are the same
;
}
} else { # - but no $opt_t specified; this is OK
;
}
} else { # No $timer found...
if ($opt_t ne '') { # - but $opt_t was specified
$timer = $opt_t; # - - so use it.
} else { # - and neither was $opt_t
warn "I can't tell what timer you have. Please specify one.\n";
usage();
exit 1;
}
}
open(DF, $driftfile) || die "Can't open driftfile ($driftfile): $!\n";
while(<DF>) {
chop;
if (/^(-?\d+\.\d+)(\s\d)?$/) {
$drift = $1;
} else {
die "Bogus value in driftfile $driftfile: <$_>\n";
}
}
close(DF);
print "NTP drift is <$drift>\n";
# Convert from NTP's idea of PPM to a decimal equivalent
$freq_adj = int ( $drift * ( 10 ** 6 / 2 ** 20) );
print "normalized freq_adj is <$freq_adj>\n";
$freq_adj = int ( ( $freq_adj - 1 ) / 2 );
print "Applying freq_adj of <".-$freq_adj.">\n";
$sysctl = "machdep.".$timer."_freq";
chop($mach_freq = `sysctl -n $sysctl`);
print "$sysctl is <$mach_freq>\n";
$n_mach_freq = $mach_freq - $freq_adj;
if (defined($opt_n)) {
print "$sysctl $mach_freq -> $n_mach_freq\n";
} else {
print "i8254: ".`sysctl -w $sysctl=$n_mach_freq`;
}
sub usage {
print STDERR <<EOUsage
Usage: $0 [-d drift_file] [-n] [-t timer]
where "drift_file" defaults to /etc/ntp.drift
and "timer" is usually "tsc" or "i8254"
and "-n" says "don't really change anything, just say what would happen".
EOUsage
}
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