Re: [GHC] #12419: Scheduling bug with forkOS + MVar

#12419: Scheduling bug with forkOS + MVar -------------------------------------+------------------------------------- Reporter: luisgabriel | Owner: Type: bug | Status: merge Priority: normal | Milestone: 8.0.2 Component: Runtime System | Version: 8.0.1 Resolution: | Keywords: forkOS; | scheduler Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2430, Wiki Page: | Phab:D2441 -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"9f1b6de8b3f788730fa5e2206fb709400299be7c/ghc" 9f1b6de8/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="9f1b6de8b3f788730fa5e2206fb709400299be7c" Fix to thread migration Summary: If we had 2 threads on the run queue, say [A,B], and B is bound to the current Task, then we would fail to migrate any threads. This fixes it so that we would migrate A in that case. This will help parallelism a bit in programs that have lots of bound threads. Test Plan: Test program in #12419, which is actually not a great program but it does behave a bit better after this change. Reviewers: ezyang, niteria, bgamari, austin, erikd Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2430 GHC Trac Issues: #12419 (cherry picked from commit 988ad8ba8e709eff3cea59728e481bb269fa6185) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12419#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler