package/qos-scripts/files/usr/lib/qos/tcrules.awk

   1 BEGIN {
   2         dmax=100
   3         if (!(linespeed > 0)) linespeed = 128
   4         FS=":"
   5         n = 0
   6 }
   7
   8 ($1 != "") {
   9         n++
  10         class[n] = $1
  11         prio[n] = $2
  12         avgrate[n] = ($3 * linespeed / 100)
  13         pktsize[n] = $4
  14         delay[n] = $5
  15         maxrate[n] = ($6 * linespeed / 100)
  16         qdisc_esfq[n] = $7
  17 }
  18
  19 END {
  20         allocated = 0
  21         maxdelay = 0
  22
  23         for (i = 1; i <= n; i++) {
  24                 # set defaults
  25                 if (!(pktsize[i] > 0)) pktsize[i] = 1500
  26                 if (!(prio[i] > 0)) prio[i] = 1
  27
  28                 allocated += avgrate[i]
  29                 sum_prio += prio[i]
  30                 if ((avgrate[i] > 0) && !(delay[i] > 0)) {
  31                         sum_rtprio += prio[i]
  32                 }
  33         }
  34
  35         # allocation of m1 in rt classes:
  36         # sum(d * m1) must not exceed dmax * (linespeed - allocated)
  37         dmax = 0
  38         for (i = 1; i <= n; i++) {
  39                 if (avgrate[i] > 0) {
  40                         rtm2[i] = avgrate[i]
  41                         if (delay[i] > 0) {
  42                                 d[i] = delay[i]
  43                         } else {
  44                                 d[i] = 2 * pktsize[i] * 1000 / (linespeed * 1024)
  45                                 if (d[i] > dmax) dmax = d[i]
  46                         }
  47                 }
  48         }
  49
  50         ds_avail = dmax * (linespeed - allocated)
  51         for (i = 1; i <= n; i++) {
  52                 lsm1[i] = 0
  53                 rtm1[i] = 0
  54                 lsm2[i] = linespeed * prio[i] / sum_prio
  55                 if ((avgrate[i] > 0) && (d[i] > 0)) {
  56                         if (!(delay[i] > 0)) {
  57                                 ds = ds_avail * prio[i] / sum_rtprio
  58                                 ds_avail -= ds
  59                                 rtm1[i] = rtm2[i] + ds/d[i]
  60                         }
  61                         lsm1[i] = rtm1[i]
  62                 }
  63                 else {
  64                         d[i] = 0
  65                 }
  66         }
  67
  68         # main qdisc
  69         for (i = 1; i <= n; i++) {
  70                 printf "tc class add dev "device" parent 1:1 classid 1:"class[i]"0 hfsc"
  71                 if (qdisc_esfq[i] != "") {
  72                         # user requested esfq
  73                         print "esfq " qdisc_esfq[i] " limit " ql
  74                 } else if (rtm1[i] > 0) {
  75                         # rt class - use sfq
  76                         printf " rt m1 " int(rtm1[i]) "kbit d " int(d[i] * 1000) "us m2 " int(rtm2[i])"kbit"
  77                 }
  78                 printf " ls m1 " int(lsm1[i]) "kbit d " int(d[i] * 1000) "us m2 " int(lsm2[i]) "kbit"
  79                 print " ul rate " int(maxrate[i]) "kbit"
  80         }
  81
  82         # leaf qdisc
  83         avpkt = 1200
  84         for (i = 1; i <= n; i++) {
  85                 printf "tc qdisc add dev "device" parent 1:"class[i]"0 handle "class[i]"00: "
  86
  87                 # RED parameters - also used to determine the queue length for sfq
  88                 # calculate min value. for links <= 256 kbit, we use 1500 bytes
  89                 # use 50 ms queue length as min threshold for faster links
  90                 # max threshold is fixed to 3*min
  91                 base_pkt=3000
  92                 base_rate=256
  93                 min_lat=50
  94                 if (maxrate[i] <= base_rate) min = base_pkt
  95                 else min = int(maxrate[i] * 1024 / 8 * 0.05)
  96                 max = 3 * min
  97                 limit = (min + max) * 3
  98
  99                 if (rtm1[i] > 0) {
 100                         # rt class - use sfq
 101                         print "sfq perturb 2 limit "  limit
 102                 } else {
 103                         # non-rt class - use RED
 104
 105                         avpkt = pktsize[i]
 106                         # don't use avpkt values less than 500 bytes
 107                         if (avpkt < 500) avpkt = 500
 108                         # if avpkt is too close to min, scale down avpkt to allow proper bursting
 109                         if (avpkt > min * 0.70) avpkt *= 0.70
 110
 111
 112                         # according to http://www.cs.unc.edu/~jeffay/papers/IEEE-ToN-01.pdf a drop
 113                         # probability somewhere between 0.1 and 0.2 should be a good tradeoff
 114                         # between link utilization and response time (0.1: response; 0.2: utilization)
 115                         prob="0.12"
 116
 117                         rburst=int((2*min + max) / (3 * avpkt))
 118                         if (rburst < 2) rburst = 2
 119                         print "red min " min " max " max " burst " rburst " avpkt " avpkt " limit " limit " probability " prob " ecn"
 120                 }
 121         }
 122
 123         # filter rule
 124         for (i = 1; i <= n; i++) {
 125                 print "tc filter add dev "device" parent 1: prio "class[i]" protocol ip handle "class[i]" fw flowid 1:"class[i] "0"
 126         }
 127 }
 128