Messages in this thread | | | From | Jesper Dangaard Brouer <> | Date | Wed, 26 Jul 2023 11:22:40 +0200 | Subject | Re: [PATCH V3,net-next] net: mana: Add page pool for RX buffers |
| |
On 25/07/2023 21.02, Haiyang Zhang wrote: > >> -----Original Message----- >> From: Jesper Dangaard Brouer <jbrouer@redhat.com> >> 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? >
If I were you, I would wait with the page_pool_nid_changed() "optimization" and do a benchmark mark to see if this actually have a benefit. (You can do this in another patch). (In a Azure hypervisor environment is might not be the right choice).
This reminds me, do you have any benchmark data on the improvement this patch (using page_pool) gave?
--Jesper
| |