Re: [PATCH net-next 5/9] eth: fbnic: Add XDP pass, drop, abort support

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Hi Mohsin,

I thought we were past the times when we read prog pointer per each
processed packet and agreed on reading the pointer once per napi loop?

This is reading the cached pointer from the netdev. Are you saying you
would rather have this as a stack pointer instead? I don't really see
the advantage to making this a once per napi poll session versus just
reading it once per packet.

Hi Alex,

this is your only reason (at least currently in this patch) to load the
cacheline from netdev struct whereas i was just suggesting to piggyback on
the fact that bpf prog pointer will not change within single napi loop.

it's up to you of course and should be considered as micro-optimization.

The cost for the "extra cacheline" should be nil as from what I can
tell xdp_prog shares the cacheline with gro_max_size and _rx so in
either path that cacheline is going to eventually be pulled in anyway
regardless of what path it goes with.

Hi Maciej,

Appreciate your suggestion regarding the micro-optimization. However, at 
this time, we are not planning to adopt this change. I am all ears to 
any further thoughts or concerns you may have about it.