On 11/02/2017 06:08 AM, Sagi Grimberg wrote: > >>>> I vaguely remember Nacking Sagi's patch as we knew it would break >>>> mlx5e netdev affinity assumptions. >> I remember that argument. Still the series found its way in. > > Of course it maid its way in, it was acked by three different > maintainers, and I addressed all of Saeed's comments. > >> That series moves affinity decisions to kernel's responsibility. >> AFAI see, what kernel does is assign IRQs to the NUMA's one by one in >> increasing indexing (starting with cores of NUMA #0), no matter what >> NUMA is closer to the NIC. > > Well, as we said before, if there is a good argument to do the home node > first we can change the generic code (as it should be given that this is > absolutely not device specific). > >> This means that if your NIC is on NUMA #1, and you reduce the number >> of channels, you might end up working only with the cores on the far >> NUMA. Not good! > We deliberated on this before, and concluded that application affinity > and device affinity are equally important. If you have a real use case > that shows otherwise, its perfectly doable to start from the device home > node.
This wasn't to start a debate about which allocation method is the perfect solution. I am perfectly happy with the new default, the part that is broken is to take away the user's option to reassign the affinity. That is a bug and it needs to be fixed! Jes
