On Fri, 15 Apr 2016 09:58:52 +0100 Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote: > There were no further responses to the last series but I kept going and > added a few more small bits. Most are basic micro-optimisations. The last > two patches weaken debugging checks to improve performance at the cost of > delayed detection of some use-after-free and memory corruption bugs. If > they make people uncomfortable, they can be dropped and the rest of the > series stands on its own. > > Changelog since v2 > o Add more micro-optimisations > o Weak debugging checks in favor of speed > [...] > > The overall impact on a page allocator microbenchmark for a range of orders I also micro benchmarked this patchset. Avail via Mel Gorman's kernel tree: http://git.kernel.org/cgit/linux/kernel/git/mel/linux.git tested branch mm-vmscan-node-lru-v5r9 which also contain the node-lru series. Tool: https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/bench/page_bench01.c Run as: modprobe page_bench01; rmmod page_bench01 ; dmesg | tail -n40 | grep 'alloc_pages order' Results kernel 4.6.0-rc1 : alloc_pages order:0(4096B/x1) 272 cycles per-4096B 272 cycles alloc_pages order:1(8192B/x2) 395 cycles per-4096B 197 cycles alloc_pages order:2(16384B/x4) 433 cycles per-4096B 108 cycles alloc_pages order:3(32768B/x8) 503 cycles per-4096B 62 cycles alloc_pages order:4(65536B/x16) 682 cycles per-4096B 42 cycles alloc_pages order:5(131072B/x32) 910 cycles per-4096B 28 cycles alloc_pages order:6(262144B/x64) 1384 cycles per-4096B 21 cycles alloc_pages order:7(524288B/x128) 2335 cycles per-4096B 18 cycles alloc_pages order:8(1048576B/x256) 4108 cycles per-4096B 16 cycles alloc_pages order:9(2097152B/x512) 8398 cycles per-4096B 16 cycles After Mel Gorman's optimizations, results from mm-vmscan-node-lru-v5r:: alloc_pages order:0(4096B/x1) 231 cycles per-4096B 231 cycles alloc_pages order:1(8192B/x2) 351 cycles per-4096B 175 cycles alloc_pages order:2(16384B/x4) 357 cycles per-4096B 89 cycles alloc_pages order:3(32768B/x8) 397 cycles per-4096B 49 cycles alloc_pages order:4(65536B/x16) 481 cycles per-4096B 30 cycles alloc_pages order:5(131072B/x32) 652 cycles per-4096B 20 cycles alloc_pages order:6(262144B/x64) 1054 cycles per-4096B 16 cycles alloc_pages order:7(524288B/x128) 1852 cycles per-4096B 14 cycles alloc_pages order:8(1048576B/x256) 3156 cycles per-4096B 12 cycles alloc_pages order:9(2097152B/x512) 6790 cycles per-4096B 13 cycles I've also started doing some parallel concurrency testing workloads[1] [1] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/bench/page_bench03.c Order-0 pages scale nicely: Results kernel 4.6.0-rc1 : Parallel-CPUs:1 page order:0(4096B/x1) ave 274 cycles per-4096B 274 cycles Parallel-CPUs:2 page order:0(4096B/x1) ave 283 cycles per-4096B 283 cycles Parallel-CPUs:3 page order:0(4096B/x1) ave 284 cycles per-4096B 284 cycles Parallel-CPUs:4 page order:0(4096B/x1) ave 288 cycles per-4096B 288 cycles Parallel-CPUs:5 page order:0(4096B/x1) ave 417 cycles per-4096B 417 cycles Parallel-CPUs:6 page order:0(4096B/x1) ave 503 cycles per-4096B 503 cycles Parallel-CPUs:7 page order:0(4096B/x1) ave 567 cycles per-4096B 567 cycles Parallel-CPUs:8 page order:0(4096B/x1) ave 620 cycles per-4096B 620 cycles And even better with you changes! :-))) This is great work! Results from mm-vmscan-node-lru-v5r: Parallel-CPUs:1 page order:0(4096B/x1) ave 246 cycles per-4096B 246 cycles Parallel-CPUs:2 page order:0(4096B/x1) ave 251 cycles per-4096B 251 cycles Parallel-CPUs:3 page order:0(4096B/x1) ave 254 cycles per-4096B 254 cycles Parallel-CPUs:4 page order:0(4096B/x1) ave 258 cycles per-4096B 258 cycles Parallel-CPUs:5 page order:0(4096B/x1) ave 313 cycles per-4096B 313 cycles Parallel-CPUs:6 page order:0(4096B/x1) ave 369 cycles per-4096B 369 cycles Parallel-CPUs:7 page order:0(4096B/x1) ave 379 cycles per-4096B 379 cycles Parallel-CPUs:8 page order:0(4096B/x1) ave 399 cycles per-4096B 399 cycles It does not seem that higher order page scale... and your patches does not change this pattern. Example order-3 pages, which is often used in the network stack: Results kernel 4.6.0-rc1 :: Parallel-CPUs:1 page order:3(32768B/x8) ave 524 cycles per-4096B 65 cycles Parallel-CPUs:2 page order:3(32768B/x8) ave 2131 cycles per-4096B 266 cycles Parallel-CPUs:3 page order:3(32768B/x8) ave 3885 cycles per-4096B 485 cycles Parallel-CPUs:4 page order:3(32768B/x8) ave 4520 cycles per-4096B 565 cycles Parallel-CPUs:5 page order:3(32768B/x8) ave 5604 cycles per-4096B 700 cycles Parallel-CPUs:6 page order:3(32768B/x8) ave 7125 cycles per-4096B 890 cycles Parallel-CPUs:7 page order:3(32768B/x8) ave 7883 cycles per-4096B 985 cycles Parallel-CPUs:8 page order:3(32768B/x8) ave 9364 cycles per-4096B 1170 cycles Results from mm-vmscan-node-lru-v5r: Parallel-CPUs:1 page order:3(32768B/x8) ave 421 cycles per-4096B 52 cycles Parallel-CPUs:2 page order:3(32768B/x8) ave 2236 cycles per-4096B 279 cycles Parallel-CPUs:3 page order:3(32768B/x8) ave 3408 cycles per-4096B 426 cycles Parallel-CPUs:4 page order:3(32768B/x8) ave 4687 cycles per-4096B 585 cycles Parallel-CPUs:5 page order:3(32768B/x8) ave 5972 cycles per-4096B 746 cycles Parallel-CPUs:6 page order:3(32768B/x8) ave 7349 cycles per-4096B 918 cycles Parallel-CPUs:7 page order:3(32768B/x8) ave 8436 cycles per-4096B 1054 cycles Parallel-CPUs:8 page order:3(32768B/x8) ave 9589 cycles per-4096B 1198 cycles -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/bench/page_bench03.c for ORDER in $(seq 0 5) ; do \ for X in $(seq 1 8) ; do \ modprobe page_bench03 page_order=$ORDER parallel_cpus=$X run_flags=$((2#100)); \ rmmod page_bench03 ; dmesg | tail -n 3 | grep Parallel-CPUs ; \ done; \ done -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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