> -----Original Message----- > From: Jesper Dangaard Brouer <jbrouer@xxxxxxxxxx> > Sent: Tuesday, July 25, 2023 2:01 PM > >> > >> Our driver is using NUMA 0 by default, so I implicitly assign NUMA node id > >> to zero during pool init. > >> > >> And, if the IRQ/CPU affinity is changed, the page_pool_nid_changed() > >> will update the nid for the pool. Does this sound good? > >> > > > > Also, since our driver is getting the default node from here: > > gc->numa_node = dev_to_node(&pdev->dev); > > I will update this patch to set the default node as above, instead of implicitly > > assigning it to 0. > > > > In that case, I agree that it make sense to use dev_to_node(&pdev->dev), > like: > pprm.nid = dev_to_node(&pdev->dev); > > Driver must have a reason for assigning gc->numa_node for this hardware, > which is okay. That is why page_pool API allows driver to control this. > > But then I don't think you should call page_pool_nid_changed() like > > page_pool_nid_changed(rxq->page_pool, numa_mem_id()); > > Because then you will (at first packet processing event) revert the > dev_to_node() setting to use numa_mem_id() of processing/running CPU. > (In effect this will be the same as setting NUMA_NO_NODE). > > I know, mlx5 do call page_pool_nid_changed(), but they showed benchmark > numbers that this was preferred action, even-when sysadm had > "misconfigured" the default smp_affinity RX-processing to happen on a > remote NUMA node. AFAIK mlx5 keeps the descriptor rings on the > originally configured NUMA node that corresponds to the NIC PCIe slot. In mana_gd_setup_irqs(), we set the default IRQ/CPU affinity to gc->numa_node too, so it won't revert the nid initial setting. Currently, the Azure hypervisor always indicates numa 0 as default. (In the future, it will start to provide the accurate default dev node.) When a user manually changes the IRQ/CPU affinity for perf tuning, we want to allow page_pool_nid_changed() to update the pool. Is this OK? Thanks, - Haiyang
