Messages in this thread | | | Date | Wed, 28 Apr 2021 09:31:24 -0700 | From | Jean Tourrilhes <> | Subject | Re: [PATCH net] openvswitch: meter: remove rate from the bucket size calculation |
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On Wed, Apr 28, 2021 at 01:22:12PM +0200, Ilya Maximets wrote: > > I didn't test it, but I looked at the implementation in > net/sched/act_police.c and net/sched/sch_tbf.c, and they should work > in a same way as this patch, i.e. it's a classic token bucket where > burst is a burst and nothing else.
Actually, act_police.c and sch_tbf.c will behave completely differently, even if they are both based on the token bucket algorithm. The reason is that sch_tbf.c is applied to a queue, and the queue will smooth out traffic and avoid drops. The token bucket is used to dequeue the queue, this is sometime called leaky bucket. I've personally used sch_tbf.c with burst size barely bigger than the MTU, and it works fine. This is why I was suggesting to compare to act_police.c, which does not have a queue to smooth out traffic and can only drop packets. I believe OVS meters are similar to policers, so that's why they are suprising for people used to queues such as TBF and HTB.
Regards,
Jean
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