Event Loop poll with no io pending is slow on macos #61843
Description
I wrote the details of this up here.
It relates to this tweet, which some of you may have seen.
To summarise:
- We could propose a change to libuv or float some patches on top of it which removes a
~12µsdelay when we poll the event loop and there is no pending io - This results in
25x(~2mticks versus~80kticks per second) better throughput forsetImmediatein the microbench provided in the gist above and on the original tweet from Jarred Sumner
Am happy to work on a PR for node.js or libuv if folks think this is worth doing and/or likely to land.
Haven't worked out the actual logic for when to set this flag yet so would likely need some feedback on that from the libuv maintainers.