Messages in this thread | | | From | Andy Lutomirski <> | Date | Thu, 25 Feb 2016 18:48:35 -0800 | Subject | Re: [PATCH 4/4] MSR: msr Batch processing feature |
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On Thu, Feb 25, 2016 at 4:02 PM, Marty McFadden <mcfadden8@llnl.gov> wrote: > Provides a new ioctl interface through /dev/cpu/msr_batch. > > This implementation will cause an Inter Processor Interrupt to be sent > to each destination processor and will wait until all processors have > finished processing their respective batch of MSR operations before > returning.
This comes up periodicially, and it needs to be benchmarked against the sane way to do it in userspace:
For each CPU: sched_setaffinity to bind to that CPU, and then a bunch of conventional MSR accesses. Optionally do all the CPUs at once using lots of threads.
Please do this benchmark on a kernel that is *not* using nohz_full. The nohz_full implementaion in current kernels has abysmal syscall performance, but that's improving rapidly.
--Andy
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