On Fri, Nov 30 2018 at 10:50am -0500, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Fri, Nov 30 2018 at 9:43am -0500, > Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > On Tue, Nov 27 2018 at 7:42pm -0500, > > Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > > > These are the patches for per-cpu in_flight counters. > > > > Do you have updated before vs after performance results for these > > changes? > > > > I'd imagine they are comparable to your previous run (though that run > > included some other DM changes that I already staged). > > Would like to see before vs after with: > > http://git.kernel.dk/cgit/linux-block/log/?h=for-4.21/block > vs > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=block-dm-4.21-inflight > > (block-dm-4.21-inflight is based on latest for-4.21/block -- and it > contains DM changes in front of the block changes from this thread; I'd > prefer Jens take the changes like this rather than leave DM in a bit of > a mess for me/us to have to cleanup later) I ran the same fio test you did (in the previous thread where you did the switch to percpu local to DM, rather than in block) _except_ I used a ramdisk-based pmem device rather than a pure ramdisk: fio --ioengine=psync --iodepth=1 --rw=read --bs=512 --direct=1 --numjobs=12 --time_based --runtime=10 --group_reporting --name=/dev/pmem0 2 6-core processors (w/ HT, so 24 logical cpus): /dev/pmem0 14.6M /dev/pmem0 with percpu counters 14.8M /dev/mapper/linear 4736k /dev/mapper/linear with percpu counters 4595k It is only after I apply this commit that I can realize a big performance win: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=block-dm-4.21-inflight&id=335b41c7513110b1519d8a93d412c138bf671263 /dev/mapper/linear with percpu + pending removed 11.2M
