From: Edward Cree <ec...@solarflare.com> Date: Wed, 9 Nov 2016 18:51:15 +0000
> On 09/11/16 18:09, David Miller wrote: >> From: Edward Cree <ec...@solarflare.com> >> Date: Tue, 8 Nov 2016 13:02:05 +0000 >> >>> On 07/11/16 18:20, David Miller wrote: >>>> From: Edward Cree <ec...@solarflare.com> >>>> Date: Thu, 3 Nov 2016 22:10:31 +0000 >>>> >>>>> EF10 based NICs have configurable RSS hash fields, and can be made to >>>>> take the >>>>> ports into the hash on UDP (they already do so for TCP). This patch >>>>> series >>>>> enables this, in order to improve spreading of UDP traffic. >>>> What does the chip do with fragmented traffic? >>> Only the first fragment will be considered UDP, it will treat the rest as >>> "other >>> IP" and 2-tuple hash them, probably hitting a different queue. >>> >>> My understanding is that while that will reduce performance, that shouldn't >>> be a >>> problem as performance-sensitive users will avoid fragmentation anyway. >>> It could also lead to out-of-order packet delivery, but it's UDP so that's >>> supposed to be OK. >> Our software hashing never tries to inspect the ports for fragmented >> frames. And I'm pretty sure this is intentional. >> >> We should minimize the difference between what we do in software, which >> we fully control, and what we ask the hardware to offload for us. >> >> If you can't configure the chip to skip the ports for fragmented frames >> than I'm going to ask you to drop this. > I just checked and it turns out I was mistaken, we don't treat the first > fragment > differently after all, we skip the ports for all fragments including the > first. > Sorry for the misinformation. That's more in line with what is expected, series applied, thanks.
