On 1/17/2023 6:37 PM, David Hildenbrand wrote: > On 17.01.23 10:19, Yin, Fengwei wrote: >> >> >> On 1/14/2023 2:13 AM, Matthew Wilcox wrote: >>> On Sat, Jan 14, 2023 at 12:35:38AM +0800, Yin Fengwei wrote: >>>> The page fault number can be reduced by batched PTEs population. >>>> The batch size of PTEs population is not allowed to cross: >>>> - page table boundaries >>>> - vma range >>>> - large folio size >>>> - fault_around_bytes >>> >>> I find this patch very interesting. But is it really worth it? Most >>> file-backed page faults are resolved through the ->map_pages() path >>> which is almost always filemap_map_pages(), which does something >>> fairly similar to this already. Do you have any performance numbers? >>> >> I tried the will-it-scale page_fault3: >> https://github.com/antonblanchard/will-it-scale/blob/master/tests/page_fault3.c >> with 96 processes on a test box with 48C/86T. >> >> The test result got about 3.75X better with 4.1X less page fault number >> with this patch. >> >> But It's a micro benchmark which shows extreme friendly case to this patch. >> >> I didn't see observed performance gain with other workloads. I suppose >> shared file write operations may not be common operations? Thanks. > > One question I have after reading "which does something fairly similar to this already", if both paths could be unified. Thanks for the suggestion. I will see what I can do for it. Regards Yin, Fengwei >
