On 7/9/20 11:20 AM, YU, Xiangning wrote:
>
>
> On 7/9/20 10:15 AM, Eric Dumazet wrote:
>>
>> Well, at Google we no longer have this issue.
>>
>> We adopted EDT model, so that rate limiting can be done in eBPF, by simply
>> adjusting skb->tstamp.
>>
>> The qdisc is MQ + FQ.
>>
>> Stanislas Fomichev will present this use case at netdev conference
>>
>> https://netdevconf.info/0x14/session.html?talk-replacing-HTB-with-EDT-and-BPF
>>
> This is cool, I would love to learn more about this!
>
> Still please correct me if I'm wrong. This looks more like pacing on a
> per-flow basis, how do you support an overall rate limiting of multiple
> flows? Each individual flow won't have a global rate usage about others.
>
No, this is really per-aggregate rate limiting, multiple TCP/UDP flows can
share the same class.
Before that, we would have between 10 and 3000 HTB classes on a host.
We had internal code to bypass the HTB (on bond0 device) for non throttled
packets,
since HTB could hardly cope with more than 1Mpps.
Now, an eBPF program (from sch_handle_egress()) using maps to perform
classification
and (optional) rate-limiting based on various rules.
MQ+FQ is already doing the per-flow pacing (we have been using this for 8 years
now)
The added eBPF code extended this pacing to be per aggregate as well.
