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Hi David, We met a performance regression(lmbench bw_mmap_rd/bw_mem) on our server with
patch 7fef431be9c9(mm/page_alloc: place pages to tail in __free_pages_core()), Case A. ./bw_mmap_rd -P 1 512m mmap_only out.file Case B. ./bw_mem -P 1 512m frd mode0: IMC Interleave = auto, Channel Interleave = auto, Rank Interleave = auto without with regression case A 10535.14 9645.02 8.4% case B 10526.88 9797.63 6.9% also we found different memory interleaving have different results mode1: IMC Interleave = 1-way, Channel Interleave = 2-way, Rank Interleave =2-way without with regression case A 10543.01 10643.12 -0.9% case B 10971.33 10853.99 1% The 7fef431be9c9 changes the different memory layout, it seems that the issue is related with memory interleave. But the patch does lead to performance regression. Any suggestion about this regression? thanks. Peng Liu |
