Per Marker Mortensen wrote:
> http://www.adsl-optimizer.dk/thesis/
> http://www.adsl-optimizer.dk/thesis/main_final.ps
>
> chapter 5, will give you extra information.
Hmm, I still haven't read all of it, but I'd like to make two
comments.
1)
I don't think the kernel patch is needed as you can fold that
information into the rate table AFAICS (See the patch at the end
of this mail). Then again, depending on the overhead value you'd
of course have a slight inaccuracy (in case the overhead is not
divisible by 2^cell_log). Thus in my patch I just assume the
worst.
2)
AFAICS you only looked at upstream shaping, right?
At least from my experience I can say that for my ADSL link
(3456kbit down / 448kbit up raw ATM speed, shared by 5 users)
it is quite easy to saturate the downstream with a bittorrent
download. So some sort of downstream shaping is needed too.
Unfortunately the IMQ patch seems to panic the kernel when it
starts dropping packets. I am currently using a shellscript
which monitors the downstream traffic and starts lowering the
upstream bandwidth limit when downstream usage is above a
threshold, which for now has stopped the complaints from the
two World of Warcraft gamers. :-)
Patch to iproute2 attached (it compiles, otherwise untested [1]).
[1] And because I need a side-effect of my slightly older patch
to the kernel currently running on the router I don't think it
will get testing from me for now... :-/
--
Tobias PGP: http://9ac7e0bc.uguu.de
diff -Naru iproute2-2.6.11-050330/tc/m_police.c iproute2-2.6.11-050330-atmpatch/tc/m_police.c
--- iproute2-2.6.11-050330/tc/m_police.c 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/m_police.c 2005-06-17 02:25:44.000000000 +0200
@@ -264,7 +264,7 @@
}
if (p.rate.rate) {
- if ((Rcell_log = tc_calc_rtable(p.rate.rate, rtab, Rcell_log, mtu, mpu)) < 0) {
+ if ((Rcell_log = tc_calc_rtable(p.rate.rate, rtab, Rcell_log, mtu, mpu, 0, 0)) < 0) {
fprintf(stderr, "TBF: failed to calculate rate table.\n");
return -1;
}
@@ -274,7 +274,7 @@
}
p.mtu = mtu;
if (p.peakrate.rate) {
- if ((Pcell_log = tc_calc_rtable(p.peakrate.rate, ptab, Pcell_log, mtu, mpu)) < 0) {
+ if ((Pcell_log = tc_calc_rtable(p.peakrate.rate, ptab, Pcell_log, mtu, mpu, 0, 0)) < 0) {
fprintf(stderr, "POLICE: failed to calculate peak rate table.\n");
return -1;
}
diff -Naru iproute2-2.6.11-050330/tc/q_cbq.c iproute2-2.6.11-050330-atmpatch/tc/q_cbq.c
--- iproute2-2.6.11-050330/tc/q_cbq.c 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/q_cbq.c 2005-06-17 02:26:07.000000000 +0200
@@ -137,7 +137,7 @@
if (allot < (avpkt*3)/2)
allot = (avpkt*3)/2;
- if ((cell_log = tc_calc_rtable(r.rate, rtab, cell_log, allot, mpu)) < 0) {
+ if ((cell_log = tc_calc_rtable(r.rate, rtab, cell_log, allot, mpu, 0, 0)) < 0) {
fprintf(stderr, "CBQ: failed to calculate rate table.\n");
return -1;
}
@@ -336,7 +336,7 @@
unsigned pktsize = wrr.allot;
if (wrr.allot < (lss.avpkt*3)/2)
wrr.allot = (lss.avpkt*3)/2;
- if ((cell_log = tc_calc_rtable(r.rate, rtab, cell_log, pktsize, mpu)) < 0) {
+ if ((cell_log = tc_calc_rtable(r.rate, rtab, cell_log, pktsize, mpu, 0, 0)) < 0) {
fprintf(stderr, "CBQ: failed to calculate rate table.\n");
return -1;
}
diff -Naru iproute2-2.6.11-050330/tc/q_htb.c iproute2-2.6.11-050330-atmpatch/tc/q_htb.c
--- iproute2-2.6.11-050330/tc/q_htb.c 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/q_htb.c 2005-06-17 02:24:11.000000000 +0200
@@ -35,12 +35,13 @@
" r2q DRR quantums are computed as rate in Bps/r2q {10}\n"
" debug string of 16 numbers each 0-3 {0}\n\n"
"... class add ... htb rate R1 [burst B1] [mpu B] [overhead O]\n"
- " [prio P] [slot S] [pslot PS]\n"
+ " [granule G] [prio P] [slot S] [pslot PS]\n"
" [ceil R2] [cburst B2] [mtu MTU] [quantum Q]\n"
" rate rate allocated to this class (class can still borrow)\n"
" burst max bytes burst which can be accumulated during idle period {computed}\n"
" mpu minimum packet size used in rate computations\n"
" overhead per-packet size overhead used in rate computations\n"
+ " granule packet size granularity (round up to granule sized units after overhead is added)\n"
" ceil definite upper class rate (no borrows) {rate}\n"
" cburst burst but for ceil {computed}\n"
@@ -108,7 +109,7 @@
unsigned buffer=0,cbuffer=0;
int cell_log=-1,ccell_log = -1;
unsigned mtu, mpu;
- unsigned char mpu8 = 0, overhead = 0;
+ unsigned char mpu8 = 0, overhead = 0, granule = 0;
struct rtattr *tail;
memset(&opt, 0, sizeof(opt)); mtu = 1600; /* eth packet len */
@@ -135,6 +136,11 @@
if (get_u8(&overhead, *argv, 10)) {
explain1("overhead"); return -1;
}
+ } else if (matches(*argv, "granule") == 0) {
+ NEXT_ARG();
+ if (get_u8(&granule, *argv, 10)) {
+ explain1("granule"); return -1;
+ }
} else if (matches(*argv, "quantum") == 0) {
NEXT_ARG();
if (get_u32(&opt.quantum, *argv, 10)) {
@@ -210,14 +216,14 @@
mpu = (unsigned)mpu8 | (unsigned)overhead << 8;
opt.ceil.mpu = mpu; opt.rate.mpu = mpu;
- if ((cell_log = tc_calc_rtable(opt.rate.rate, rtab, cell_log, mtu, mpu)) < 0) {
+ if ((cell_log = tc_calc_rtable(opt.rate.rate, rtab, cell_log, mtu, mpu, overhead, granule)) < 0) {
fprintf(stderr, "htb: failed to calculate rate table.\n");
return -1;
}
opt.buffer = tc_calc_xmittime(opt.rate.rate, buffer);
opt.rate.cell_log = cell_log;
- if ((ccell_log = tc_calc_rtable(opt.ceil.rate, ctab, cell_log, mtu, mpu)) < 0) {
+ if ((ccell_log = tc_calc_rtable(opt.ceil.rate, ctab, cell_log, mtu, mpu, overhead, granule)) < 0) {
fprintf(stderr, "htb: failed to calculate ceil rate table.\n");
return -1;
}
diff -Naru iproute2-2.6.11-050330/tc/q_tbf.c iproute2-2.6.11-050330-atmpatch/tc/q_tbf.c
--- iproute2-2.6.11-050330/tc/q_tbf.c 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/q_tbf.c 2005-06-17 02:26:28.000000000 +0200
@@ -170,7 +170,7 @@
opt.limit = lim;
}
- if ((Rcell_log = tc_calc_rtable(opt.rate.rate, rtab, Rcell_log, mtu, mpu)) < 0) {
+ if ((Rcell_log = tc_calc_rtable(opt.rate.rate, rtab, Rcell_log, mtu, mpu, 0, 0)) < 0) {
fprintf(stderr, "TBF: failed to calculate rate table.\n");
return -1;
}
@@ -178,7 +178,7 @@
opt.rate.cell_log = Rcell_log;
opt.rate.mpu = mpu;
if (opt.peakrate.rate) {
- if ((Pcell_log = tc_calc_rtable(opt.peakrate.rate, ptab, Pcell_log, mtu, mpu)) < 0) {
+ if ((Pcell_log = tc_calc_rtable(opt.peakrate.rate, ptab, Pcell_log, mtu, mpu, 0, 0)) < 0) {
fprintf(stderr, "TBF: failed to calculate peak rate table.\n");
return -1;
}
diff -Naru iproute2-2.6.11-050330/tc/tc_core.c iproute2-2.6.11-050330-atmpatch/tc/tc_core.c
--- iproute2-2.6.11-050330/tc/tc_core.c 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/tc_core.c 2005-06-17 02:23:09.000000000 +0200
@@ -47,11 +47,9 @@
*/
int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu,
- unsigned mpu)
+ unsigned mpu, unsigned overhead, unsigned granularity)
{
int i;
- unsigned overhead = (mpu >> 8) & 0xFF;
- mpu = mpu & 0xFF;
if (mtu == 0)
mtu = 2047;
@@ -65,8 +63,14 @@
unsigned sz = (i<<cell_log);
if (overhead)
sz += overhead;
+ /* FIXME: Maybe the mpu check should be done before adding the overhead */
if (sz < mpu)
sz = mpu;
+ /* Round up to specified granularity, usefull for ATM based links (ADSL) */
+ if (granularity) {
+ sz += granularity - 1;
+ sz -= sz % granularity;
+ }
rtab[i] = tc_core_usec2tick(1000000*((double)sz/bps));
}
return cell_log;
diff -Naru iproute2-2.6.11-050330/tc/tc_core.h iproute2-2.6.11-050330-atmpatch/tc/tc_core.h
--- iproute2-2.6.11-050330/tc/tc_core.h 2005-04-01 21:58:11.000000000 +0200
+++ iproute2-2.6.11-050330-atmpatch/tc/tc_core.h 2005-06-17 02:22:53.000000000 +0200
@@ -7,7 +7,8 @@
long tc_core_usec2tick(long usec);
long tc_core_tick2usec(long tick);
unsigned tc_calc_xmittime(unsigned rate, unsigned size);
-int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu, unsigned mpu);
+int tc_calc_rtable(unsigned bps, __u32 *rtab, int cell_log, unsigned mtu,
+ unsigned mpu, unsigned overhead, unsigned granularity);
int tc_setup_estimator(unsigned A, unsigned time_const, struct tc_estimator *est);
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