Beats me! The author no longer works at Google from what I can tell—emails to him bounced.

I'd love to see 1:1 threading become competitive with M:N for the heaviest workloads. It just plays so much nicer with the outside world than M:N does.

> I'd love to see 1:1 threading become competitive with M:N for the heaviest workloads. It just plays so much nicer with the outside world than M:N does.

After working lots of years with all of the available async paradigms (eventloops, promises, async-await, observables, etc) I would tend to agree. Even though many of those things (including Rusts futures implementation) are very well-engineered, the integration problems (as e.g. outlined in the what color is your function article) are very real. And the extra amount of understanding that is required to use and implement those technologies might often not justify the gains. One basically needs to understand normal threaded-synchronization as well as async-synchronization (e.g. as with .NET Tasks or Rusts futures) to build things on top of it. Same goes for the extra level of type indirection (Task<T> vs T), or the distinction between "hot" and "cold" tasks/promises.

If it would be possible to get 1:1 threading into the same performance region for most normal applications (e.g. everything but a 1 million connection servers) it seems to very favorable.