[PATCH 0/3] [FHI:linux-azure] CONFIG_RT_GROUP_SCHED=y

[Tim Gardner]

BugLink: https://bugs.launchpad.net/bugs/1939024

[Impact]

Microsoft has requested that CONFIG_RT_GROUP_SCHED be enabled. This option has
no discernible runtime impact in the default case. As quoted from research
performed by Colin King, "I ran some synthetic stress-ng throughput and
latency tests with and without CONFIG_RT_GROUP_SCHED on CONFIG_RT_GROUP_SCHED.
I don't see enough variation in the throughput or latency to warrant any concern
about enabling this option. We have quite a bit of small jitter on the results,
but overall the kernel results are similar enough to make me feel OK to enable
this option for Focal."

[Fix]

CONFIG_RT_GROUP_SCHED=y

[Test Case]

Microsoft has tested this option using kernels at
https://kernel.ubuntu.com/~rtg/azure-rt-group-sched-sf00314473/. The customer
requesting this config option verified that it satisfied their requirements.
Microsft also determined that there were no performance regressions for the default
case, i.e., when no RT priority threads were created.

[Where problems could occur]

Adding options to the scheduler could impact work loads that we have yet to observe.

[Other Info]

SF: 00314473