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A processor could use that as a hint to optimize based > on the full extent size. AMD Zen uarchs, as an example, elide > allocation of cachelines for regions larger than L3-size. > > Demand faulting a 64GB region shows good performance improvements: > > $ perf bench mem map -p $page-size -f demand -s 64GB -l 5 > > mm/folio_zero_user x86/folio_zero_user change > (GB/s +- %stdev) (GB/s +- %stdev) > > pg-sz=2MB 11.82 +- 0.67% 16.48 +- 0.30% + 39.4% > pg-sz=1GB 17.51 +- 1.19% 40.03 +- 7.26% [#] +129.9% > > [#] Only with preempt=full|lazy because cooperatively preempted models > need regular invocations of cond_resched(). This limits the extent > sizes that can be cleared as a unit. > > Raghavendra also tested on AMD Genoa and that shows similar > improvements [1]. > [...] Sorry for coming back late on this: It was nice to have it integrated to perf bench mem (easy to test :)). I do see similar (almost same) improvement again with the rebased kernel and patchset. Tested only preempt=lazy and boost=1 base 6.16-rc4 + 1-9 patches of this series patched = 6.16-rc4 + all patches SUT: Genoa+ AMD EPYC 9B24 $ perf bench mem map -p $page-size -f populate -s 64GB -l 10 base patched change pg-sz=2MB 12.731939 GB/sec 26.304263 GB/sec 106.6% pg-sz=1GB 26.232423 GB/sec 61.174836 GB/sec 133.2% for 4kb page size there is a slight improvement (mostly a noise). Thanks and Regards - Raghu