Re: Pause and unpause queue

Dave Taht <[email protected]> writes:

> On Sat, Jan 7, 2023 at 10:08 AM team lnx <[email protected]> wrote:
>>
>> sure, during xdp redirect i found that sometimes the number of packets
>> arrived are too many for an interface
>
> That is often the case.
>
>> to handle in which case. Hence thought to experiment with tx pause to
>> make room for successive packets and then unpause !
>
> "pauses" are really not how the internet works, there needs to be end
> to end signalling to "slow down", either via packet loss, or marking.
> RFC970 is a good read here.

Actually it is, kinda, at this level: Pausing the TX interface (when the
HWQ is full) is how the regular network stack creates backpressure
against the qdisc, which is what allows fq_codel and friends to
function. This is missing entirely from the XDP redirect path, which is
what we're trying to fix...

-Toke