NIOPosix on Darwin: inherit main thread QoS #2944
Merged
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Motivation:
On Darwin, QoS (quality of service) of threads plays an important role, especially on Apple Silicon machines with P-cores and E-cores. If you spawn raw threads (like NIOPosix) and use a mechanism that doesn't support QoS propagation (like reading/writing to networks -- like NIOPosix does), it's recommended to default to the main thread's QoS.
Otherwise you'll always be at the default QoS for "legacy" threads which means bad latencies, especially on Apple Silicon machines.
In a follow-up PR #2943 we're adding better configurability for thread configuration.
Modifications:
Default to main thread QoS on Darwin.
Result:
Better latencies for applications with higher QoS classes.