Re: Blocking a task indefinitely in the RTS

I'm trying to model an Asynchronous I/O call/interface against a synchronous Haskell call. I want the behavior of an unsafe blocking foreign call, without blocking in the foreign call itself. On Tue, Jan 8, 2019 at 6:24 PM Carter Schonwald wrote:

What’s the underlying problem you’re trying to model?

On Tue, Jan 8, 2019 at 3:56 AM Phyx wrote:

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Oh, I see :( I guess it's not that easy of a fix then. Perhaps the RTS could use a new intrinsic for blocking on foreign state

Yeah, that's what I was/am currently working on, "IOPort" has much of the same property of MVar but doesn't have this deadlock guarantee and only supports a single put/take at a time. But debugging CMM is... not fun :( so I was wondering if I was just missing something with the existing mechanisms.

On Tue, Jan 8, 2019 at 8:23 AM Phil Ruffwind wrote:

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I did try removing this check to see, but it really didn't like that. It caused GC to be triggered over and over again as the RTS tried desperately to find something to do, doesn't seem to consider "do nothing" as a valid state.

Oh, I see :( I guess it's not that easy of a fix then. Perhaps the RTS could use a new intrinsic for blocking on foreign state.

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