在 2023/10/23 20:21, Matthew Wilcox 写道:
On Mon, Oct 23, 2023 at 04:07:28PM +0800, zhiguojiang wrote:
Are you seeing measurable changes for any workloads? It certainly seems
like you should, but it would help if you chose a test from mmtests and
showed how performance changed on your system.
In one mmtest, the max times for a invalid recyling of a folio_list dirty
folio that does not support pageout and has been activated in
shrink_folio_list() are: cost=51us, exe=2365us.
Calculate according to this formula: dirty_cost / total_cost * 100%, the
recyling efficiency of dirty folios can be improved 53.13%、82.95%.
So this patch can optimize shrink efficiency and reduce the workload of
kswapd to a certain extent.
kswapd0-96 ( 96) [005] ..... 387.218548:
mm_vmscan_lru_shrink_inactive: [Justin] nid 0 nr_scanned 32 nr_taken 32
nr_reclaimed 31 nr_dirty 1 nr_unqueued_dirty 1 nr_writeback 0
nr_activate[1] 1 nr_ref_keep 0 f RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
total_cost 96 total_exe 2365 dirty_cost 51 total_exe 2365
kswapd0-96 ( 96) [006] ..... 412.822532:
mm_vmscan_lru_shrink_inactive: [Justin] nid 0 nr_scanned 32 nr_taken 32
nr_reclaimed 0 nr_dirty 32 nr_unqueued_dirty 32 nr_writeback 0
nr_activate[1] 19 nr_ref_keep 13 f RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
total_cost 88 total_exe 605 dirty_cost 73 total_exe 605
I appreciate that you can put probes in and determine the cost, but do
you see improvements for a real workload? Like doing a kernel compile
-- does it speed up at all?
Can you help share a method for testing thread workload, like kswapd?
Thanks.
