Yeah, Christophe had the magic touch; that turns off RT throttling. On Thu, Oct 13, 2022 at 4:14 PM Sebastian Kuzminsky <seb@xxxxxxxxxxx> wrote: > > On 10/13/22 00:07, Christophe Blaess wrote: > > Hi > > > > On 13/10/2022 01:25, Sebastian Kuzminsky wrote: > >> Thanks for the suggestion, but it gives results that are only slightly > >> better: > > > > > > It will probably make no difference as you run your task on an isolcpu > > but did you set `sysctl kernel.sched_rt_runtime_us=-1` > > Wow, this plus Clark's suggestion to run with SCHED_FIFO priority 2 > fixed it, thank you!! > > With those two changes I now get identical, awesome results with > SCHED_OTHER:0 and SCHED_FIFO:2 (running on an isolcpu): > > > $ sudo sysctl kernel.sched_rt_runtime_us=-1 > > kernel.sched_rt_runtime_us = -1 > > $ sudo ./busy > > using PTHREAD_EXPLICT_SCHED to set SCHED_FIFO (with highest priority) > > scheduling policy: SCHED_FIFO > > scheduling parameter priority: 2 (min=1, max=99) > > cpu affinity: 3 > > after 10000 iterations: > > min=54001 cycles (1000.019 us, 1.000 ms) > > avg=54002.001 cycles (1000.037 us, 1.000 ms) > > max=54004 cycles (1000.074 us, 1.000 ms) > > OK: worst latency < 2 ms > > > > using PTHREAD_INHERIT_SCHED to keep SCHED_OTHER (with default priority) > > scheduling policy: SCHED_OTHER > > scheduling parameter priority: 0 (min=0, max=0) > > cpu affinity: 3 > > after 10000 iterations: > > min=54001 cycles (1000.019 us, 1.000 ms) > > avg=54002.001 cycles (1000.037 us, 1.000 ms) > > max=54004 cycles (1000.074 us, 1.000 ms) > > OK: worst latency < 2 ms > > Thank you Christophe and Clark! > > > -- > Sebastian Kuzminsky >
