On Wed, 2022-04-13 at 14:52 +0530, Jagdish Gediya wrote: > Sharing used_targets between multiple nodes in a single > pass limits some of the opportunities for demotion target > sharing. > > Don't share the used targets between multiple nodes in a > single pass, instead accumulate all the used targets in > source nodes shared by all pass, and reset 'used_targets' > to source nodes while finding demotion targets for any new > node. > > This results into some more opportunities to share demotion > targets between multiple source nodes, e.g. with below NUMA > topology, where node 0 & 1 are cpu + dram nodes, node 2 & 3 > are equally slower memory only nodes, and node 4 is slowest > memory only node, > > available: 5 nodes (0-4) > node 0 cpus: 0 1 > node 0 size: n MB > node 0 free: n MB > node 1 cpus: 2 3 > node 1 size: n MB > node 1 free: n MB > node 2 cpus: > node 2 size: n MB > node 2 free: n MB > node 3 cpus: > node 3 size: n MB > node 3 free: n MB > node 4 cpus: > node 4 size: n MB > node 4 free: n MB > node distances: > node 0 1 2 3 4 > 0: 10 20 40 40 80 > 1: 20 10 40 40 80 > 2: 40 40 10 40 80 > 3: 40 40 40 10 80 > 4: 80 80 80 80 10 > > The existing implementation gives below demotion targets, > > node demotion_target > 0 3, 2 > 1 4 > 2 X > 3 X > 4 X > > With this patch applied, below are the demotion targets, > > node demotion_target > 0 3, 2 > 1 3, 2 > 2 4 > 3 4 > 4 X > > e.g. with below NUMA topology, where node 0, 1 & 2 are > cpu + dram nodes and node 3 is slow memory node, > > available: 4 nodes (0-3) > node 0 cpus: 0 1 > node 0 size: n MB > node 0 free: n MB > node 1 cpus: 2 3 > node 1 size: n MB > node 1 free: n MB > node 2 cpus: 4 5 > node 2 size: n MB > node 2 free: n MB > node 3 cpus: > node 3 size: n MB > node 3 free: n MB > node distances: > node 0 1 2 3 > 0: 10 20 20 40 > 1: 20 10 20 40 > 2: 20 20 10 40 > 3: 40 40 40 10 > > The existing implementation gives below demotion targets, > > node demotion_target > 0 3 > 1 X > 2 X > 3 X > > With this patch applied, below are the demotion targets, > > node demotion_target > 0 3 > 1 3 > 2 3 > 3 X > With the [PATCH v1], you have describe the demotion order changes for the following system, I guess there's no change with [PATCH v2]? With below NUMA topology, where node 0 & 2 are cpu + dram nodes and node 1 & 3 are slow memory nodes, available: 4 nodes (0-3) node 0 cpus: 0 1 node 0 size: n MB node 0 free: n MB node 1 cpus: node 1 size: n MB node 1 free: n MB node 2 cpus: 2 3 node 2 size: n MB node 2 free: n MB node 3 cpus: node 3 size: n MB node 3 free: n MB node distances: node 0 1 2 3 0: 10 40 20 80 1: 40 10 80 80 2: 20 80 10 40 3: 80 80 40 10 And, what is the demotion order for the following system with [PATCH v2]? Node 0 & 2 are cpu + dram nodes and node 1 are slow memory node near node 0, available: 3 nodes (0-2) node 0 cpus: 0 1 node 0 size: n MB node 0 free: n MB node 1 cpus: node 1 size: n MB node 1 free: n MB node 2 cpus: 2 3 node 2 size: n MB node 2 free: n MB node distances: node 0 1 2 0: 10 40 20 1: 40 10 80 2: 20 80 10 Best Regards, Huang, Ying [snip]
