Hi Kevin,
On Jun 6, 2015, at 17:46 , Kevin Darbyshire-Bryant
<[email protected]> wrote:
>
>
> On 06/06/15 15:29, Sebastian Moeller wrote:
>> 1) ATM interface 'backpressure' - is this Byte Queue Limits? (ifxmips_atm)
>> Is there actual backpreassure from your ATM diver at all? As rar as I
>> know france’s free had their boxes ATM driver modified to keep buffering
>> low, and I believe David Woodhouse dd some work on another driver/the
>> generic ATM layer, but I am not sure that any ATM driver actually defaults
>> to sane buffering and sane back pressure.
> That was my sort of point. On 'planet Kevin' (don't go there) the ATM driver
> would *know* the link is busy, or how many bytes it still had to shove over
> it and could offer some clue back up the stack to not bloat. I thought
> that's what BQL was supposed to do. Or another way of viewing: If ethernet
> interfaces ideally implement BQL why shouldn't ATM?
Ah, I fully agree that is how I would like it to be as well;
unfortunately that is not sufficient to make it happen though :(
>
>>
>>
>> How this is supposed to work? In an ideal work the CPE and the DSLAM
>> would not over-buffer and www would not have to dedicate grey matter to work
>> around their sort-commings ;) But as far as I can tell DSL sync rates for
>> many lines are stable over weeks to months, so setting the shaper rarely is
>> sufficient. Like when you notice that latency under load got worse…
> Well again on 'planet Kevin' the CPE is OpenWrt.
A planet I like to live on from what I learned about it.
> Apparenly it's under my control but I'm fighting my own lack of abilities,
> trying to sprint a marathon before I can even crawl. Looking at kernel
> sources when I can barely get 'hello world' to compile & run is asking for
> trouble :-) About a day ago I didn't know what an SKB was.
> https://www.coverfire.com/articles/queueing-in-the-linux-network-stack/ has
> been a revelation.
This sounds like you embark on fixing the del driver in your modem;
more power to you then.
Best Regards
Sebastian
>>
>> Best Regards
>> Sebastian
>>
>
>
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