Why does Dagr use the physical processor count instead of logical for Macs only?

[clintval]

On my MacBook Pro with hyper-threading enabled I have 8 physical cores yet 16 addressable cores.

❯ sysctl -n hw.physicalcpu
8
❯ sysctl -n hw.logicalcpu
16

dagr/core/src/main/scala/dagr/core/execsystem/Resource.scala

Lines 33 to 38 in e2a634a

	/** Total number of cores in the system */
	val systemCores : Cores =
	if (hal.isInstanceOf[MacHardwareAbstractionLayer])
	Cores(this.hal.getProcessor.getPhysicalProcessorCount)
	else
	Cores(this.hal.getProcessor.getLogicalProcessorCount)

I may be under-utilizing my local compute resources if capped to 8 cores instead of the full 16. Here's a screenshot of when I ask Dagr to run a task with the maximum allowed system cores:

Since hyper-threading is not unique to Macs, I am wondering why this design decision was made.

[nh13]

Pinging @tfenne if he can remember as I don't. You can override this with --cores 16 in the short-term.