On Tue, Feb 07, 2023 at 01:32:20PM -0700, Patel, Nirmal wrote: > On 2/6/2023 8:18 PM, Xinghui Li wrote: > > Keith Busch <kbusch@xxxxxxxxxx> 于2023年2月7日周二 02:28写道： > >> I suspect bypass is the better choice if "num_active_cpus() > pci_msix_vec_count(vmd->dev)". > > For this situation, My speculation is that the PCIE nodes are > > over-mounted and not just because of the CPU to Drive ratio. > > We considered designing online nodes, because we were concerned that > > the IO of different chunk sizes would adapt to different MSI-X modes. > > I privately think that it may be logically complicated if programmatic > > judgments are made. > > Also newer CPUs have more MSIx (128) which means we can still have > better performance without bypass. It would be better if user have > can chose module parameter based on their requirements. Thanks. So what? More vectors just pushes the threshold to when bypass becomes relevant, which is exactly why I suggested it. There has to be an empirical answer to when bypass beats muxing. Why do you want a user tunable if there's a verifiable and automated better choice?
