Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 10b4d364 by Duncan Coutts at 2026-02-17T17:04:52-05:00 Fix errors in the documentation of the eventlog STOP_THREAD status codes Fix the code for BlockedOnMsgThrowTo. Document all the known historical warts. Fixes issue #26867 - - - - - 1 changed file: - docs/users_guide/eventlog-formats.rst Changes: ===================================== docs/users_guide/eventlog-formats.rst ===================================== @@ -221,14 +221,41 @@ Thread and scheduling events * 11: BlockedOnDelay * 12: BlockedOnSTM * 13: BlockedOnDoProc - * 16: BlockedOnMsgThrowTo + * 14--17: unused + * 18: BlockedOnMsgThrowTo + * 19: unused * 20: BlockedOnMVarRead :field ThreadId: thread id of thread being blocked on (only for some status values) The indicated thread has stopped running for the reason given by ``status``. - + + Historically, the GHC-internal status codes for the reasons why threads are + blocked were used more-or-less directly as the status codes emitted into the + eventlog. This is now recognised as a mistake and the GHC internal codes and + these eventlog stop thread codes are now independent. We are nevertheless + left with some historical warts: + + * 14,15: these correspond to GHC internal status codes `BlockedOnGA` and + `BlockedOnGA_NoSend` that are no longer used (and may never have been + used by any released version of GHC). + * 16,17: these would be used by `BlockedOnCCall` and + `BlockedOnCCall_Interruptible` which are GHC-internal status codes, but + these are never and have never been emitted into the eventlog. This has + caused confusion, and many versions of the `ghc-events` package support + these status codes. Threads blocking on foreign calls use `ForeignCall` + above. + * 19: this would be used by `ThreadMigrating` which is a GHC-internal + status code, but this is never emitted into the eventlog. Threads + migrating use a separate event `MIGRATE_THREAD`. + * `BlockedOnMsgGlobalise`: this is supported by versions of `ghc-events` as + code 18, but it appears never to have been emitted by any released version + of GHC. Most likely it was related to the local-heap GC experiment that + was never released. + + Errata: previous versions of this document stated that code 16 is + `BlockedOnMsgThrowTo`. It appears this was always incorrect. .. event-type:: MIGRATE_THREAD View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/10b4d3641f6fe7a7443bd621d62d1355... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/10b4d3641f6fe7a7443bd621d62d1355... You're receiving this email because of your account on gitlab.haskell.org.