From: Andre Guedes <redacted>
Date: Jan/09/2020, 01:07:37 (UTC+00:00)

After reading all this great discussion and revisiting the 802.1Q and 802.3br
specs, I'm now leaning towards to not coupling Frame Preemption support under
taprio qdisc. Besides what have been discussed, Annex S.2 from 802.1Q-2018
foresees FP without EST so it makes me feel like we should keep them separate.

I agree that EST and FP can be used individually. But how can you 
specify the hold and release commands for gates without changing taprio qdisc user space API ?

Regarding the FP configuration knobs, the following seems reasonable to me:
    * Enable/disable FP feature
    * Preemptable queue mapping
    * Fragment size multiplier

I'm not sure about the knob 'timers (hold/release)' described in the quotes
above. I couldn't find a match in the specs. If it refers to 'holdAdvance' and
'releaseAdvance' parameters described in 802.1Q-2018, I believe they are not
configurable. Do we know any hardware where they are configurable?

Synopsys' HW supports reconfiguring these parameters. They are, however, 
fixed independently of Queues. i.e. all queues will have same holdAdvance / releaseAdvance.

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Thanks,
Jose Miguel Abreu