Messages in this thread | | | Date | Tue, 24 Oct 2023 09:07:52 +0200 | Subject | Re: [PATCH v2 1/2] mm:vmscan: the dirty folio in folio_list skip unmap | From | David Hildenbrand <> |
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On 24.10.23 04:04, zhiguojiang wrote: > > > 在 2023/10/23 21:01, Matthew Wilcox 写道: >> On Mon, Oct 23, 2023 at 08:44:55PM +0800, zhiguojiang wrote: >>> 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? >> Something dirt simple like 'time make -j8'. > Two compilations were conducted separately, and compared to the > unmodified compilation, > the compilation time for adding modified patches had a certain > reduction, as follows: > > Compilation command: > make distclean -j8 > make ARCH=x86_64 x86_64_defconfig > time make -j8 > > 1.Unmodified Compilation time: > real 2m40.276s > user 16m2.956s > sys 2m14.738s > > real 2m40.136s > user 16m2.617s > sys 2m14.722s > > 2.[Patch v2 1/2] Modified Compilation time: > real 2m40.067s > user 16m3.164s > sys 2m14.211s > > real 2m40.123s > user 16m2.439s > sys 2m14.508s > > 3 [Patch v2 1/2] + [Patch v2 2/2] Modified Compilation time: > real 2m40.367s > user 16m3.738s > sys 2m13.662s > > real 2m40.014s > user 16m3.108s > sys 2m14.096s >
To get expressive numbers two iterations are usually not sufficient. How much memory does you system have? Does vmscan even ever get active?
-- Cheers,
David / dhildenb
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