Today I setup htb on a system of mine that I needed to control bandwidth
for.
I read the documentation and setup a config that seems to be working
fine.
Unfortunately, there's a problem where randomly for between 1 and a
couple of seconds, almost no packets are sent out, or are delayed
significantly.
This is the output from a script I got from a friend. It does some
simple difference averaging with a 10 second period. Notice the period
of 0.13 Mb/s. That's not supposed to happen.
eth0: 0.04 Mb/s In 1.68 Mb/s Out - 116.3 p/s In 180.7 p/s Out
eth0: 0.04 Mb/s In 1.59 Mb/s Out - 82.1 p/s In 130.4 p/s Out
eth0: 0.04 Mb/s In 1.60 Mb/s Out - 123.1 p/s In 184.8 p/s Out
eth0: 0.01 Mb/s In 0.13 Mb/s Out - 33.3 p/s In 53.9 p/s Out
eth0: 0.05 Mb/s In 1.53 Mb/s Out - 63.2 p/s In 89.6 p/s Out
eth0: 0.05 Mb/s In 1.76 Mb/s Out - 119.4 p/s In 180.9 p/s Out
At the same time I ran a ping to the host as well:
64 bytes from xxx.xxx.xxx.20: icmp_seq=488 ttl=58 time=75.8 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=489 ttl=58 time=75.6 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=490 ttl=58 time=75.6 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=491 ttl=58 time=80.4 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=492 ttl=58 time=75.7 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=493 ttl=58 time=111 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=495 ttl=58 time=1370 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=497 ttl=58 time=2695 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=499 ttl=58 time=700 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=504 ttl=58 time=135 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=506 ttl=58 time=81.8 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=507 ttl=58 time=75.4 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=508 ttl=58 time=75.6 ms
64 bytes from xxx.xxx.xxx.20: icmp_seq=509 ttl=58 time=75.7 ms
I also ran a ping to a host sitting right next to it on the same switch.
It did not see the same increase in latency.
Load on the system was negligble at the time of the "blip".
Also, in my logs was this message:
HTB: mindelay=500, report it please !
Here's the jist of my config:
tc add dev eth0 root handle 1: htb default 12
tc class add dev eth0 parent 1: classid 1:1 htb \
rate 2016kbit ceil 2016kbit
tc class add dev eth0 parent 1:1 classid 1:10 htb \
rate 768kbit ceil 2016kbit prio 0
tc class add dev eth0 parent 1:1 classid 1:11 htb \
rate 256kbit ceil 1920kbit prio 2
tc class add dev eth0 parent 1:1 classid 1:12 htb \
rate 1024kbit ceil 2016kbit prio 1
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 \
match ip tos 0x10 0xff flowid 1:10
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 \
match ip protocol 1 0xff flowid 1:10
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 \
match ip src xxx.xxx.xxx.119 flowid 1:11
tc qdisc add dev eth0 parent 1:10 handle 20: sfq perturb 10
tc qdisc add dev eth0 parent 1:11 handle 21: sfq perturb 10
tc qdisc add dev eth0 parent 1:12 handle 22: sfq perturb 10
Anyone have any idea what be causing the "blip"? It's noticable because
for that period of time, all of my ssh sessions become very slow and
laggy, and then everything speeds up again. In fact, it happened as I
was writing this email too.
JE
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