I've come across what I think are more than one distinct bugs in running `atomic-counter`'s benchmarks. If we are able to discern them later ahead we can create a separate ticket. The easiest to reproduce is an immediate segfault on start with 9.6.1 and HEAD which doesn't occur with other versions. Simply clone `atom-counter` and run `cabal run bench -- -j1` with `9.1`. Note that any value passed with `-j` will cause the segfault. Omitting the `-j` flag will make the program no longer segfault. The other is bug seems to be related to concurrency/atomic operations. I was able to somewhat reliably reproduce by running `cabal bench` with `9.6`, and could reproduce another crash with `9.4` but less reliably. ``` $ cabal bench All Correctness: OK (3.49s) +++ OK, passed 10000 tests. Read/write contention with 10 iterations and 1 threads Counter: OK (0.45s) 18.1 μs ± 1.6 μs IORef inconsistent: OK (1.83s) 18.1 μs ± 1.7 μs, 1.00x IORef atomic: OK (1.05s) 20.1 μs ± 1.6 μs, 1.11x MVar: OK (1.00s) 18.9 μs ± 1.3 μs, 1.04x TMVar: OK (0.57s) 22.7 μs ± 1.6 μs, 1.25x TVar: OK (1.17s) 22.6 μs ± 1.8 μs, 1.25x Addr: OK (0.47s) 17.3 μs ± 1.7 μs, 0.96x Read/write contention with 100 iterations and 1 threads Counter: OK (0.66s) 26.4 μs ± 1.7 μs IORef inconsistent: OK (0.39s) 29.2 μs ± 2.4 μs, 1.11x IORef atomic: OK (1.76s) 39.1 μs ± 2.6 μs, 1.48x MVar: OK (0.43s) 32.6 μs ± 3.2 μs, 1.24x TMVar: bench: internal error: TSO object (0x16d65ee40) entered! (GHC version 9.6.1 for aarch64_apple_darwin) Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug Benchmark bench: ERROR Error: cabal: Benchmarks failed for bench:bench from atomic-counter-0.1. ``` Architecture: aarch64 (Apple Silicon)