Messages in this thread | | | Date | Sun, 28 Jul 2019 15:31:02 +0200 | From | Pavel Machek <> | Subject | Re: [RFC v4 0/8] TurboSched: A scheduler for sustaining Turbo Frequencies for longer durations |
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Hi!
> Abstract > ======== > > The modern servers allows multiple cores to run at range of frequencies > higher than rated range of frequencies. But the power budget of the system > inhibits sustaining these higher frequencies for longer durations.
Thermal budget?
Should this go to documentation somewhere?
> Current CFS algorithm in kernel scheduler is performance oriented and hence > tries to assign any idle CPU first for the waking up of new tasks. This > policy is perfect for major categories of the workload, but for jitter > tasks, one can save energy by packing them onto the active cores and allow > those cores to run at higher frequencies. > > These patch-set tunes the task wake up logic in scheduler to pack > exclusively classified jitter tasks onto busy cores. The work involves the > jitter tasks classifications by using syscall based mechanisms. > > In brief, if we can pack jitter tasks on busy cores then we can save power > by keeping other cores idle and allow busier cores to run at turbo > frequencies, patch-set tries to meet this solution in simplest manner. > Though, there are some challenges in implementing it(like smt_capacity,
Space before (.
> These numbers are w.r.t. `turbo_bench.c` multi-threaded test benchmark > which can create two kinds of tasks: CPU bound (High Utilization) and > Jitters (Low Utilization). N in X-axis represents N-CPU bound and N-Jitter > tasks spawned.
Ok, so you have description how it causes 13% improvements. Do you also have metrics how it harms performance.. how much delay is added to unimportant tasks etc...?
Thanks, Pavel
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