[LARTC] HTB traffic shaping odd effects

[Oliver Hookins]

Andy Furniss wrote:
> Oliver Hookins wrote:
> 
>> Hi,
>>
>> I'm trying to perform some (what I consider) basic traffic shaping on 
>> our network utilising HTB. I have mostly reused the example on the 
>> lartc.org site:
>>
>> tc qdisc add dev eth0 root handle 1: htb default 10
>> tc class add dev eth0 parent 1: classid 1:1 htb rate 100mbit burst 24k
>> tc class add dev eth0 parent 1:1 classid 1:10 htb rate 50mbit ceil
>> 80mbit burst 19k
> 
> 
> burst 19k will limit you unless your HZ=1000

Our HZ is 512.

>> tc class add dev eth0 parent 1:1 classid 1:20 htb rate 1mbit ceil
>> 1mbit
>> tc qdisc add dev eth0 parent 1:10 handle 10: sfq perturb 10
>> tc qdisc add dev eth0 parent 1:20 handle 20: sfq perturb 10
>> tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 match ip src
>> X.X.X.X flowid 1:20
>>
>> So we have a total of 100mbit to be used, the default class 1:10 gets 
>> 50mbit and a ceiling of 80mbit whereas my test host X.X.X.X gets only 
>> 1mbit in any situation. Some rate limiting is definitely happening, 
>> but I am finding the outbound traffic is limited to 2mbit instead of 
>> 1mbit. If I change the rate (to say 10mbit) the outbound traffic gets 
>> up to again twice the rate (in this case 20mbit).
> 
> 
> Not sure can you show output of tc -s -d class ls dev eth0 while it's 
> running at 2x speed.

class htb 1:1 root rate 100Mbit ceil 100Mbit burst 24Kb/8 mpu 0b cburst 
132644b/8 mpu 0b level 7
  Sent 741267447736 bytes 735629628 pkts (dropped 0, overlimits 0)
  rate 4316188bps 22688pps
  lended: 489885589 borrowed: 0 giants: 0
  tokens: -78 ctokens: 6677

class htb 1:10 parent 1:1 leaf 10: prio 0 quantum 200000 rate 50Mbit 
ceil 80Mbit burst 19Kb/8 mpu 0b cburst 106440b/8 mpu 0b level 0
  Sent 740240463634 bytes 734522966 pkts (dropped 429910165, overlimits 0)
  rate 4233957bps 22358pps
  lended: 244988819 borrowed: 489885528 giants: 0
  tokens: -293 ctokens: 6636

class htb 1:20 parent 1:1 leaf 20: prio 0 quantum 13107 rate 1Mbit ceil 
1Mbit burst 2Kb/8 mpu 0b cburst 2Kb/8 mpu 0b level 0
  Sent 755354078 bytes 755048 pkts (dropped 0, overlimits 0)
  rate 84198bps 321pps backlog 4p
  lended: 755220 borrowed: 61 giants: 0
  tokens: -21517 ctokens: -21517


-- 
Regards,
Oliver Hookins