[LARTC] HTB traffic shaping odd effects

[Andy Furniss]

Oliver Hookins wrote:

>> burst 19k will limit you unless your HZ=1000
> 
> Our HZ is 512.
> 

I don't know if it makes any difference, but I would have chosen 500 so 
that it was 2ms. The default now is 250 and with 19k burst that fits the 
speed you get really well - with 512 it would be around 70meg. I would 
get rid of the 2 burst settings you use.

>> 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

84198 bps - tc means bytes/sec by this, so it's < 1mbit. Htb uses really 
long (100 sec) average for its rate so it probably is giving 1mbit.

Andy.