mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-11-02 02:11:32 +02:00
cbddbcdae4
- rewrite the RED qdisc calculations and add some comments this should fix the warnings about bursting (should also fix quirks with various linespeed settings) - reduce the calculated overhead for upstream, while i'm at it... git-svn-id: svn://svn.openwrt.org/openwrt/trunk@7782 3c298f89-4303-0410-b956-a3cf2f4a3e73
124 lines
3.0 KiB
Awk
124 lines
3.0 KiB
Awk
BEGIN {
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dmax=100
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if (!(linespeed > 0)) linespeed = 128
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FS=":"
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n = 0
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}
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($1 != "") {
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n++
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class[n] = $1
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prio[n] = $2
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avgrate[n] = ($3 * linespeed / 100)
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pktsize[n] = $4
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delay[n] = $5
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maxrate[n] = ($6 * linespeed / 100)
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}
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END {
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allocated = 0
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maxdelay = 0
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for (i = 1; i <= n; i++) {
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# set defaults
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if (!(pktsize[i] > 0)) pktsize[i] = 1500
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if (!(prio[i] > 0)) prio[i] = 1
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allocated += avgrate[i]
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sum_prio += prio[i]
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if ((avgrate[i] > 0) && !(delay[i] > 0)) {
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sum_rtprio += prio[i]
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}
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}
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# allocation of m1 in rt classes:
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# sum(d * m1) must not exceed dmax * (linespeed - allocated)
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dmax = 0
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for (i = 1; i <= n; i++) {
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if (avgrate[i] > 0) {
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rtm2[i] = avgrate[i]
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if (delay[i] > 0) {
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d[i] = delay[i]
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} else {
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d[i] = 2 * pktsize[i] * 1000 / (linespeed * 1024)
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if (d[i] > dmax) dmax = d[i]
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}
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}
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}
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ds_avail = dmax * (linespeed - allocated)
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for (i = 1; i <= n; i++) {
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lsm1[i] = 0
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rtm1[i] = 0
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lsm2[i] = linespeed * prio[i] / sum_prio
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if ((avgrate[i] > 0) && (d[i] > 0)) {
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if (!(delay[i] > 0)) {
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ds = ds_avail * prio[i] / sum_rtprio
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ds_avail -= ds
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rtm1[i] = rtm2[i] + ds/d[i]
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}
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lsm1[i] = rtm1[i]
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}
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else {
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d[i] = 0
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}
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}
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# main qdisc
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for (i = 1; i <= n; i++) {
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printf "tc class add dev "device" parent 1:1 classid 1:"class[i]"0 hfsc"
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if (rtm1[i] > 0) {
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printf " rt m1 " int(rtm1[i]) "kbit d " int(d[i] * 1000) "us m2 " int(rtm2[i])"kbit"
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}
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printf " ls m1 " int(lsm1[i]) "kbit d " int(d[i] * 1000) "us m2 " int(lsm2[i]) "kbit"
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print " ul rate " int(maxrate[i]) "kbit"
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}
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# leaf qdisc
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avpkt = 1200
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for (i = 1; i <= n; i++) {
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printf "tc qdisc add dev "device" parent 1:"class[i]"0 handle "class[i]"00: "
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# RED parameters - also used to determine the queue length for sfq
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# calculate min value. for links <= 256 kbit, we use 1500 bytes
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# use 50 ms queue length as min threshold for faster links
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# max threshold is fixed to 3*min
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base_pkt=3000
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base_rate=256
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min_lat=50
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if (maxrate[i] <= base_rate) min = base_pkt
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else min = int(maxrate[i] * 1024 / 8 * 0.05)
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max = 3 * min
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limit = (min + max) * 3
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if (rtm1[i] > 0) {
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# rt class - use sfq
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print "sfq perturb 2 limit " limit
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} else {
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# non-rt class - use RED
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avpkt = pktsize[i]
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# don't use avpkt values less than 500 bytes
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if (avpkt < 500) avpkt = 500
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# if avpkt is too close to min, scale down avpkt to allow proper bursting
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if (avpkt > min * 0.70) avpkt *= 0.70
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# according to http://www.cs.unc.edu/~jeffay/papers/IEEE-ToN-01.pdf a drop
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# probability somewhere between 0.1 and 0.2 should be a good tradeoff
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# between link utilization and response time (0.1: response; 0.2: utilization)
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prob="0.12"
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rburst=int((2*min + max) / (3 * avpkt))
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if (rburst < 2) rburst = 2
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print "red min " min " max " max " burst " rburst " avpkt " avpkt " limit " limit " probability " prob " ecn"
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}
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}
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# filter rule
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for (i = 1; i <= n; i++) {
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print "tc filter add dev "device" parent 1: prio "class[i]" protocol ip handle "class[i]" fw flowid 1:"class[i] "0"
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}
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}
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