Hi, You should not use isolcpus, but use cpuset instead. isolcpus disables task load balancing from the scheduler on the isolated cpu, which is not the case using cpuset.
On Fri, Feb 13, 2026 at 5:18 PM r r <[email protected]> wrote: > Hi, > > let's look at the example: > > The system is running with the following kernel parameters: > > isolcpus=10, nohz_full=10, nohz=on, idle=poll, intel_pstate=disable. > > We have a thread *T* that uses Thread.onSpinWait() while polling a > lock-free shared queue. In this context, the *task interval* refers to > the time elapsed between adding consecutive tasks to the queue. > > When thread *T* is pinned to CPU #10 and the task interval is set to 1ms, > the average task execution time is *100 µs*. However, when the task > interval is increased to 40ms on the same pinned core, the average > execution time significantly degrades to *250 µs*. > > In contrast, when thread *T* is unpinned, the performance remains much > more consistent. At a 1ms task interval, the average execution time is *110 > µs*, and it only slightly increases to *120 µs* when the interval is > extended to 40ms. > > -- > You received this message because you are subscribed to the Google Groups > "mechanical-sympathy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion, visit > https://groups.google.com/d/msgid/mechanical-sympathy/4fbbd936-a784-45b2-a58e-61a292aad704n%40googlegroups.com > <https://groups.google.com/d/msgid/mechanical-sympathy/4fbbd936-a784-45b2-a58e-61a292aad704n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/mechanical-sympathy/CALrzOLsr3w%3D6T_yPwpL4j%3DJqu5ZBjmSP6cDF4ar7dnZQ0H2VfQ%40mail.gmail.com.
