Messages in this thread | | | From | Aubrey Li <> | Date | Wed, 24 Apr 2019 21:13:10 +0800 | Subject | Re: [RFC PATCH v2 00/17] Core scheduling v2 |
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On Wed, Apr 24, 2019 at 12:18 AM Vineeth Remanan Pillai <vpillai@digitalocean.com> wrote: > > Second iteration of the core-scheduling feature. > > This version fixes apparent bugs and performance issues in v1. This > doesn't fully address the issue of core sharing between processes > with different tags. Core sharing still happens 1% to 5% of the time > based on the nature of workload and timing of the runnable processes. > > Changes in v2 > ------------- > - rebased on mainline commit: 6d906f99817951e2257d577656899da02bb33105
Thanks to post v2, based on this version, here is my benchmarks result.
Environment setup -------------------------- Skylake server, 2 numa nodes, 104 CPUs (HT on) cgroup1 workload, sysbench (CPU intensive non AVX workload) cgroup2 workload, gemmbench (AVX512 workload)
Case 1: task number < CPU num -------------------------------------------- 36 sysbench threads in cgroup1 36 gemmbench threads in cgroup2
core sched off: - sysbench 95th percentile latency(ms): avg = 4.952, stddev = 0.55342 core sched on: - sysbench 95th percentile latency(ms): avg = 3.549, stddev = 0.04449
Due to core cookie matching, sysbench tasks won't be affect by AVX512 tasks, latency has ~28% improvement!!!
Case 2: task number > CPU number ------------------------------------------------- 72 sysbench threads in cgroup1 72 gemmbench threads in cgroup2
core sched off: - sysbench 95th percentile latency(ms): avg = 11.914, stddev = 3.259 core sched on: - sysbench 95th percentile latency(ms): avg = 13.289, stddev = 4.863
So not only power, now security and performance is a pair of contradictions. Due to core cookie not matching and forced idle introduced, latency has ~12% regression.
Any comments?
Thanks, -Aubrey
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