On Mon, 12 Feb 2018 18:42:21 +0100 Christophe LEROY <christophe.le...@c-s.fr> wrote:
> Le 12/02/2018 à 16:24, Nicholas Piggin a écrit : > > On Mon, 12 Feb 2018 16:02:23 +0100 > > Christophe LEROY <christophe.le...@c-s.fr> wrote: > > > >> Le 10/02/2018 à 09:11, Nicholas Piggin a écrit : > >>> This series intends to improve performance and reduce stack > >>> consumption in the slice allocation code. It does it by keeping slice > >>> masks in the mm_context rather than compute them for each allocation, > >>> and by reducing bitmaps and slice_masks from stacks, using pointers > >>> instead where possible. > >>> > >>> checkstack.pl gives, before: > >>> 0x00000de4 slice_get_unmapped_area [slice.o]: 656 > >>> 0x00001b4c is_hugepage_only_range [slice.o]: 512 > >>> 0x0000075c slice_find_area_topdown [slice.o]: 416 > >>> 0x000004c8 slice_find_area_bottomup.isra.1 [slice.o]: 272 > >>> 0x00001aa0 slice_set_range_psize [slice.o]: 240 > >>> 0x00000a64 slice_find_area [slice.o]: 176 > >>> 0x00000174 slice_check_fit [slice.o]: 112 > >>> > >>> after: > >>> 0x00000d70 slice_get_unmapped_area [slice.o]: 320 > >>> 0x000008f8 slice_find_area [slice.o]: 144 > >>> 0x00001860 slice_set_range_psize [slice.o]: 144 > >>> 0x000018ec is_hugepage_only_range [slice.o]: 144 > >>> 0x00000750 slice_find_area_bottomup.isra.4 [slice.o]: 128 > >>> > >>> The benchmark in https://github.com/linuxppc/linux/issues/49 gives, > >>> before: > >>> $ time ./slicemask > >>> real 0m20.712s > >>> user 0m5.830s > >>> sys 0m15.105s > >>> > >>> after: > >>> $ time ./slicemask > >>> real 0m13.197s > >>> user 0m5.409s > >>> sys 0m7.779s > >> > >> Hi, > >> > >> I tested your serie on an 8xx, on top of patch > >> https://patchwork.ozlabs.org/patch/871675/ > >> > >> I don't get a result as significant as yours, but there is some > >> improvment anyway: > >> > >> ITERATION 500000 > >> > >> Before: > >> > >> root@vgoip:~# time ./slicemask > >> real 0m 33.26s > >> user 0m 1.94s > >> sys 0m 30.85s > >> > >> After: > >> root@vgoip:~# time ./slicemask > >> real 0m 29.69s > >> user 0m 2.11s > >> sys 0m 27.15s > >> > >> Most significant improvment is obtained with the first patch of your serie: > >> root@vgoip:~# time ./slicemask > >> real 0m 30.85s > >> user 0m 1.80s > >> sys 0m 28.57s > > > > Okay, thanks. Are you still spending significant time in the slice > > code? > > Do you mean am I still updating my patches ? No I hope we are at last Actually I was wondering about CPU time spent for the microbenchmark :) > run with v4 now that Aneesh has tagged all of them as reviewed-by himself. > Once the serie has been accepted, my next step will be to backport at > least the 3 first ones in kernel 4.14 > > > > >> > >> Had to modify your serie a bit, if you are interested I can post it. > >> > > > > Sure, that would be good. > > Ok, lets share it. The patch are not 100% clean. Those look pretty good, thanks for doing that work. Thanks, Nick
