[Cake] Getting Cake to work better with Steam and similar applications

[Sebastian Moeller]

> On Apr 20, 2017, at 18:05, Dendari Marini <dendari92 at gmail.com> wrote:
> 
> Hello, thanks for your reply.
> 
> Looks like most of your options are okay, including the correct “dual” modes and “ingress” mode in the right place.  However, I think you need to adjust your bandwidth and overhead settings, otherwise Cake isn’t reliably in control of the bottleneck queues.  Try these to begin with:
> 
> … bandwidth 850Kbit conservative dual-srchost nat
> 
> … bandwidth 15Mbit conservative dual-dsthost nat ingress
> 
> That should give you correct operation, and you can fine-tune from there.
> 
> Just did quick test with your settings. First thing I noticed is my final download bandwidth is about 12Mbps, Steam on PC1 downloads at 1.4-1.5MB/s while downloading a file on PC2 seems to max out at ~250KB/s. From my understanding I should see each PC download at ~700KB/s, or am I mistaken?

Assuming you measured good put in [M|K]iBytes this adds up to  1.5+0.25 = 1.75 * 1024^2 * 8 = 14680064 Bits or (1.4+0.25) * 8 *1024^2 / 1000^2 = 13.84 Mbps which seems a bit high for a 16Mbps ADSL link. I would ecpext something like 16 * (48/53)  * ((1500 - 8 - 20 -20) / (1500 + 32)) = 13.73 Mbps TCP/IPv4 goodput… so you seem to be running close to theoretical maximum of your link (assuming I am not totally off with the overhead (estimated ADSL overhead on top of MTU: 6 destination MAC + 6 source MAC + 2 ethertype + 3 ATM LLC + 5 ATM SNAP + 2 ATM pad + 8 ATM AAL5 SAR 32 bytes). But with your shaper set at 15Mbps without the atm option you will actually accept up to 15 * (53/48) = 16.5625 Mbps on the wire, which probably is above your link bandwidth. This fits well with the really low number of drops in your cake stats, you simply never have cake feel that shaping is needed?

Best Regards




> 
> On 20 April 2017 at 17:32, Jonathan Morton <chromatix99 at gmail.com> wrote:
> 
>> On 20 Apr, 2017, at 18:23, Dendari Marini <dendari92 at gmail.com> wrote:
>> 
>>> Could you post the output of calling “tc -s qdisc” here on the list please? That should allow to figure out what you actually told cake to do ;0
> 
>> qdisc cake 8001: dev eth0 root refcnt 2 bandwidth 900Kbit diffserv3 dual-srchost nat rtt 100.0ms raw
> 
>> qdisc cake 8002: dev ifb4eth0 root refcnt 2 bandwidth 16Mbit diffserv3 dual-dsthost nat ingress rtt 100.0ms raw
> 
> Looks like most of your options are okay, including the correct “dual” modes and “ingress” mode in the right place.  However, I think you need to adjust your bandwidth and overhead settings, otherwise Cake isn’t reliably in control of the bottleneck queues.  Try these to begin with:
> 
> … bandwidth 850Kbit conservative dual-srchost nat
> 
> … bandwidth 15Mbit conservative dual-dsthost nat ingress
> 
> That should give you correct operation, and you can fine-tune from there.
> 
> - Jonathan Morton
> 
> 
>