On 11/13/2025 9:38 AM, Ming Lei wrote:
On Wed, Nov 12, 2025 at 11:02:47AM +0800, Guo, Wangyang wrote:
On 11/11/2025 8:08 PM, Ming Lei wrote:
On Tue, Nov 11, 2025 at 01:31:04PM +0800, Guo, Wangyang wrote:
They still should share same L3 cache, and cpus_share_cache() should be
true when the IO completes on the CPU which belong to different L2 with the
submission CPU, and remote completion via IPI won't be triggered.
Yes, remote IPI not triggered.
OK, in my test on AMD zen4, NVMe performance can be dropped to 1/2 - 1/3 if
remote IPI is triggered in case of crossing L3, which is understandable.
I will check if topo cluster can cover L3, if yes, the patch still can be
simplified a lot by introducing sub-node spread by changing
build_node_to_cpumask()
and adding nr_sub_nodes.
Do you mean using cluster as "NUMA" nodes to spread CPU, instead of two
level NUMA-cluster spreading?
BR
Wangyang
