Re: [LARTC] tc shown rate larger than ceil (was "Weird rate in HTB")

[Andy Furniss <lists@andyfurniss.entadsl.com>]

Stonie Cooper wrote:
> An earlier exchange about someone seeing the rate larger than the 
> ceiling is posted below.  Andy explained the reason for the "above 
> ceiling" rate in Daniel's output . . . but I just saw an example that 
> doesn't fit.
>  >> tc output >>
> class htb 1:14 parent 1:1 leaf 14: prio 1 quantum 3072 rate 256000bit 
> ceil 282000bit burst 1820b/8 mpu 0b overhead 0b cburst 1851b/8 mpu 0b 
> overhead 0b level 0
> Sent 2639448 bytes 1128 pkt (dropped 0, overlimits 0 requeues 0)
> rate 325360bit 17pps backlog 0b 25p requeues 0
> lended: 981 borrowed: 122 giants: 1155
It's because you have giants - possibly because your nic does tcp 
segmentation offload so locally generated traffic goes through htb as 
big chunks before it gets segmented down to the nic's mtu.
You can check/turn that off with ethtool -k or you could use htb's mtu 
parameter for each rate (I'm not sure if you need to do ceils aswell) 
which makes the granularity of the rate table bigger so it can handle 
the larger mtu.
Andy.
_______________________________________________
LARTC mailing list
LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc