On Wed, Nov 06, 2019 at 04:40:07AM -0700, Jon Derrick wrote: > In order to provide better affinity alignment along the entire storage > stack, VMD IRQ lists can be assigned to in a manner where the underlying > IRQ can be affinitized the same as the child (NVMe) device. > > This patch changes the assignment of child device vectors in IRQ lists > from a round-robin strategy to a matching-entry strategy. NVMe > affinities are deterministic in a VMD domain when these devices have the > same vector count as limited by the VMD MSI domain or cpu count. When > one or more child devices are attached on a VMD domain, this patch > aligns the NVMe submission-side affinity with the VMD completion-side > affinity as it completes through the VMD IRQ list. This really only works if the child devices have the same irq count as the vmd device. If the vmd device has more interrupts than the child devices, this will end up overloading the lower vmd interrupts without even using the higher ones.
