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authorStephen Hemminger <stephen.hemminger@vyatta.com>2010-07-20 08:51:45 -0700
committerStephen Hemminger <stephen.hemminger@vyatta.com>2010-07-20 08:51:45 -0700
commit8c0855223c04240da56d2ba59e14675432dd88ab (patch)
tree483020f5156ad7aea31efa9f5fc28d9ba1d0474a /lib
parent133ab82f5c0f10f320c46ebfcdf8b109674e6734 (diff)
downloadvyatta-cfg-qos-8c0855223c04240da56d2ba59e14675432dd88ab.tar.gz
vyatta-cfg-qos-8c0855223c04240da56d2ba59e14675432dd88ab.zip
Expose RED values as constant
This makes RED more robust since constant values are visible.
Diffstat (limited to 'lib')
-rw-r--r--lib/Vyatta/Qos/ShaperClass.pm44
1 files changed, 25 insertions, 19 deletions
diff --git a/lib/Vyatta/Qos/ShaperClass.pm b/lib/Vyatta/Qos/ShaperClass.pm
index 6b474e6..0eaede2 100644
--- a/lib/Vyatta/Qos/ShaperClass.pm
+++ b/lib/Vyatta/Qos/ShaperClass.pm
@@ -23,6 +23,10 @@ require Vyatta::Config;
use Vyatta::Qos::Match;
use Vyatta::Qos::Util qw/getDsfield getRate/;
+use constant {
+ AVGPKT => 1024, # Average packet size for RED calculations
+ LATENCY => 250, # Worstcase latency for RED (ms)
+};
sub new {
my ( $that, $config, $id ) = @_;
@@ -117,27 +121,24 @@ sub rateCheck {
exit 1;
}
+ my $qlimit = $self->{_limit};
if ($self->{_qdisc} eq 'random-detect') {
- my $avg = 1024;
- my $qmax = ( $rate * 100 ) / 8000;
- my $qlimit = $self->{_limit};
- if (defined($qlimit) && $qlimit * $avg < $qmax) {
+ my $qmax = redQsize($rate);
+ if (defined($qlimit) && $qlimit * AVGPKT < $qmax) {
print STDERR "Configuration error in: $level\n";
printf STDERR
"The queue limit (%d) is too small, must be greater than %d when using random-detect\n",
- $level, $qmax / $avg;
+ $level, $qmax / AVGPKT;
exit 1;
}
- # The assumptions about average packet size and allowable latency
- # result in limit on available bandwidth
- #
- # 2 * Avg pkt = (BW * Latency) / 8 bit/byte
- # 16K bits = BW * .1 sec
- if ($qmax < $avg) {
+ if ($qmax < 3 * AVGPKT) {
+ my $minbw = (3 * AVGPKT * 8) / LATENCY;
+
print STDERR "Configuration error in: $level\n";
die
-"Random-detect queue type requires effective bandwidth of 160 Kbit/sec or greater\n";
+"Random-detect queue type requires effective bandwidth of %d Kbit/sec or greater\n",
+ $minbw;
}
}
}
@@ -189,19 +190,24 @@ sub fifoQdisc {
#
# These are based on Sally Floyd's recommendations:
# http://www.icir.org/floyd/REDparameters.txt
-#
+sub redQsize {
+ my $bw = shift;
+
+ return ($bw * LATENCY) / (8 * 1000);
+}
+
sub redQdisc {
my ( $self, $dev, $rate ) = @_;
- my $avg = 1024;
- my $qmax = (defined $rate) ? (( $rate * 100 ) / 8000) : (18 * $avg);
+ my $qmax = (defined $rate) ? redQsize( $rate ) : (18 * AVGPKT);
my $qmin = $qmax / 3;
- $qmin = $avg if $qmin < $avg;
+ $qmin = AVGPKT if $qmin < AVGPKT;
- my $burst = ( 2 * $qmin + $qmax ) / (3 * $avg);
+ my $burst = ( 2 * $qmin + $qmax ) / (3 * AVGPKT);
my $limit = $self->{_limit};
- my $qlimit = (defined $limit) ? ($limit * $avg) : (4 * $qmax);
+ my $qlimit = (defined $limit) ? ($limit * AVGPKT) : (4 * $qmax);
- printf "red limit %d min %d max %d avpkt %d", $qlimit, $qmin, $qmax, $avg;
+ printf "red limit %d min %d max %d avpkt %d",
+ $qlimit, $qmin, $qmax, AVGPKT;
printf " burst %d probability 0.1 bandwidth %s ecn\n", $burst, $rate;
}