#15555: Finish separating the stable name and stable pointer tables -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: task | Status: new Priority: normal | Milestone: 8.8.1 Component: Runtime System | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by dfeuer: Old description:

The stable name table and stable pointer table are both implemented in `rts/Stable.c`, with their code interleaved. As far as I can tell, they basically don't share ''anything''—or at least anything that they actually ''should''. They ''do'' share a mutex, which smells like a terrible idea. Doesn't that just introduce contention between `StableName` and `StablePtr` operations in different threads? They also share an initialization function, `initStableTables`, that appears to allocate both a stable name table and a stable pointer table as soon as either of them is needed. Unless I'm missing something, there's no point whatsoever in doing that. So I think we should actually divide `Stable.c` into `StableName.c` and `StablePtr.c` and give each its own mutex.

New description: The stable name table and stable pointer table are both implemented in `rts/Stable.c`, with their code interleaved. Presumably this is for historical reasons; they were once one table, and they were split for performance reasons (see #7674). As far as I can tell, they basically don't share ''anything''—or at least anything that they actually ''should''. They ''do'' share a mutex, which smells like a terrible idea. Doesn't that just introduce contention between `StableName` and `StablePtr` operations in different threads? They also share an initialization function, `initStableTables`, that appears to allocate both a stable name table and a stable pointer table as soon as either of them is needed. Unless I'm missing something, there's no point whatsoever in doing that. So I think we should actually divide `Stable.c` into `StableName.c` and `StablePtr.c` and give each its own mutex. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15555#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15555: Finish separating the stable name and stable pointer tables -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: task | Status: patch Priority: normal | Milestone: 8.8.1 Component: Runtime System | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #7674 | Differential Rev(s): Phab:D5084 Wiki Page: | -------------------------------------+------------------------------------- Changes (by dfeuer): * related: => #7674 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15555#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#15555: Finish separating the stable name and stable pointer tables -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: task | Status: patch Priority: normal | Milestone: 8.8.1 Component: Runtime System | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #7674 | Differential Rev(s): Phab:D5084 Wiki Page: | -------------------------------------+------------------------------------- Comment (by David Feuer ): In [changeset:"f48e276a5ba68d8b6fcb4a558022581fb30f9326/ghc" f48e276a/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f48e276a5ba68d8b6fcb4a558022581fb30f9326" Finish stable split Long ago, the stable name table and stable pointer tables were one. Now, they are separate, and have significantly different implementations. I believe the time has come to finish the split that began in #7674. * Divide `rts/Stable` into `rts/StableName` and `rts/StablePtr`. * Give each table its own mutex. * Add FFI functions `hs_lock_stable_ptr_table` and `hs_unlock_stable_ptr_table` and document them. These are intended to replace the previously undocumented `hs_lock_stable_tables` and `hs_lock_stable_tables`, which are now documented as deprecated synonyms. * Make `eqStableName#` use pointer equality instead of unnecessarily comparing stable name table indices. Reviewers: simonmar, bgamari, erikd Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15555 Differential Revision: https://phabricator.haskell.org/D5084 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15555#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler