Tomohiro Misono (Fujitsu) [off-list ref] writes:

quoted

Subject: [PATCH v6 00/10] Enable haltpoll on arm64

This patchset enables the cpuidle-haltpoll driver and its namesake
governor on arm64. This is specifically interesting for KVM guests by
reducing IPC latencies.

Comparing idle switching latencies on an arm64 KVM guest with
perf bench sched pipe:

                                     usecs/op       %stdev

  no haltpoll (baseline)               13.48       +-  5.19%
  with haltpoll                         6.84       +- 22.07%

I got similar results with VM on Grace machine (applied to 6.10).

Great. Thanks for testing.

[default]
# cat /sys/devices/system/cpu/cpuidle/current_driver
none
# perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes

     Total time: 23.832 [sec]

      23.832644 usecs/op
          41959 ops/sec

[With "cpuidle-haltpoll.force=1" commandline]
# cat /sys/devices/system/cpu/cpuidle/current_driver
haltpoll
# perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes

     Total time: 6.340 [sec]

       6.340116 usecs/op
         157725 ops/sec

Tested-by: Misono Tomohiro <redacted>

Thanks!

--
ankur