#9539: TQueue can lead to thread starvation -------------------------------------+------------------------------------- Reporter: jwlato | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 7.8.2 Resolution: | Keywords: stm Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by jonsterling): * cc: core-libraries-committee@… (added) Comment: We (PivotCloud) are running up against this problem currently (it is causing live-locking in our production code) and are curious if a patch would be accepted to make the change described in the ticket (i.e. change the case statement to a let binding). Incidentally, in Simon Marlowe's book, he explicitly mentions that one should use a lazy let here instead of a case statement, but somehow this did not make it into the actual implementation of TQueue. See http://chimera.labs.oreilly.com/books/1230000000929/ch10.html#CO37-2 Also, I don't know how releases for STM work---is it plausible that we could fix this quickly and get out a new version of STM, or would a better path forward for our immediate need be to just make a custom (copy-and- paste) version of TQueue with this fix? We are happy to submit a patch in either case. Thanks! Jon Sterling & Lars Kuhtz PivotCloud Inc -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9539#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler