On Sun, Mar 21, 2021 at 01:51:56PM -0700, Shakeel Butt wrote: > We noticed that the cost of psi increases with the increase in the > levels of the cgroups. Particularly the cost of cpu_clock() sticks out > as the kernel calls it multiple times as it traverses up the cgroup > tree. This patch reduces the calls to cpu_clock(). > > Performed perf bench on Intel Broadwell with 3 levels of cgroup. > > Before the patch: > > $ perf bench sched all > # Running sched/messaging benchmark... > # 20 sender and receiver processes per group > # 10 groups == 400 processes run > > Total time: 0.747 [sec] > > # Running sched/pipe benchmark... > # Executed 1000000 pipe operations between two processes > > Total time: 3.516 [sec] > > 3.516689 usecs/op > 284358 ops/sec > > After the patch: > > $ perf bench sched all > # Running sched/messaging benchmark... > # 20 sender and receiver processes per group > # 10 groups == 400 processes run > > Total time: 0.640 [sec] > > # Running sched/pipe benchmark... > # Executed 1000000 pipe operations between two processes > > Total time: 3.329 [sec] > > 3.329820 usecs/op > 300316 ops/sec > > Signed-off-by: Shakeel Butt <shake...@google.com>
Acked-by: Johannes Weiner <han...@cmpxchg.org>
