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Wen Kokke pushed to branch wip/wenkokke/trace-ipe at Glasgow Haskell Compiler / GHC

Commits:

eb922183

by Duncan Coutts at 2026-05-07T14:28:50+01:00

Add a rts posix FdWakup utility module

This will be used to implement wakeupIOManager for in-RTS I/O managers.

It provides a notification/wakeup mechanism using FDs, suitable for
situations when a thread is blocked on a set of fds anyway. It uses the
classic self-pipe trick, or equivalently eventfd on supported platforms.

This will initially be used to implement prompt interrupt or shutdown of
the posix ticker thread.

01b0e233

by Duncan Coutts at 2026-05-07T14:28:50+01:00

Add prompt shutdown to the pthread ticker implementation.

The Linux timerfd ticker monitors a pipe which is used by exitTicker to
ensure a prompt wakeup and shutdown. The pthread ticker lacked this and
so would only exit at the next ticker wakeup (10ms by default).

This patch adds the same mechanism to the pthread ticker.

This changes the pthread ticker from waiting by using nanosleep() to
waiting using either ppoll() or select(), so that it can wait on both
a time and a file descriptor. On Linux at least, a test program to
compare the timing jitter of these APIs shows that using nanpsleep,
ppoll or select makes no statistical difference to the maximum or
average jitter.

This is a step towards unifying the posix ticker implementations, so
that we can have just one portable one (albeit with some limited cpp).
It is also a step towards using the ticker as part of a more general
implementation of wakeUpRts, since this will require a method to wake
the rts from a signal handler context (ctl-c handler).

bc41d646

by Duncan Coutts at 2026-05-07T14:28:50+01:00

Update ticker header commentary

It was antique and didn't apply even to the previous implementation, and
certainly not to the updated one.

4ed9a386

by Duncan Coutts at 2026-05-07T14:28:50+01:00

Remove the timerfd-based ticker implementation

There does not appear to be any remaining advantage on Linux to using
the timerfd ticker implementation over the portable one (using ppoll on
Linux for precise timing).

The eventfd implementation was originally added at a time when Linux was
still using a signal based implementation. So it made sense at the time.
See (closed) issue #10840.

97504fa6

by Duncan Coutts at 2026-05-07T14:28:50+01:00

Consolidate to a single posix ticker implementation

Previously we had four implementations, two using signals and two using
threads. Having just one should make behaviour more consistent between
platforms, and should make maintenance easier.

1e60023b

by Facundo Domínguez at 2026-05-07T18:01:16-04:00

Generalize so_inline to specify which bindings should be preserved

This commit generalizes the so_inline option of the simple optimizer
so we can indicate with a predicate the specific bindings that should
be kept.

This feature is important for the LiquidHaskell plugin, which relies on the
simple optimizer to make core programs easier to read, but needs to preserve
bindings that are relevant for verification.

See https://gitlab.haskell.org/ghc/ghc/-/issues/24386 for the full discussion.

44cf9cd7
by Wolfgang Jeltsch at 2026-05-12T09:48:18-04:00
```
Move the `Text.Read` implementation into `base`
```

4ac3f7d6

by Vladislav Zavialov at 2026-05-12T09:49:03-04:00

EPA: Use AnnParen for tuples and sums

Summary of changes

* Do not use AnnParen in XListTy, replace it with EpToken "[" and "]"
* Specialise AnnParen to tuple/sums by dropping the AnnParensSquare
  and keeping only AnnParens and AnnParensHash
* Use AnnParen in XExplicitTuple
* Use AnnParen in XExplicitTupleTy
* Use AnnParen in XTuplePat
* Use AnnParen in XExplicitSum (via AnnExplicitSum)
* Use AnnParen in XSumPat (via EpAnnSumPat)

This is a refactoring with no user-facing changes.

1bdcddec