From: Christopher Baines <mail@cbaines.net>
To: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Cc: 70474@debbugs.gnu.org
Subject: bug#70474: Possible bug with `atomic-box-swap!` on OSX/M3 (?!?!)
Date: Fri, 19 Apr 2024 14:19:52 +0100 [thread overview]
Message-ID: <87o7a54hhj.fsf@cbaines.net> (raw)
In-Reply-To: <825897f1-19fa-4f6a-b459-8db93791d1c3@leastfixedpoint.com> (Tony Garnock-Jones's message of "Fri, 19 Apr 2024 12:54:32 +0200")
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Tony Garnock-Jones <tonyg@leastfixedpoint.com> writes:
> I'm seeing some very strange behaviour from `atomic-box-swap!` (but
> not `atomic-box-compare-and-swap!`) on Guile 3.0.9 from Homebrew on
> OSX Sonoma using an M3 Pro cpu. The issue does not seem to manifest on
> x86_64. Could it be some interaction between Guile and M3 CPUs?
>
> Or am I just doing something very silly that shouldn't work at all and
> just happens to look like it works on x86_64?
>
> Here's the program that fails. It will run for a few hundred million
> rounds and then yield "q null in get". Note that using CAS seems to
> work, but plain old swap doesn't.
There are known issue(s) with Guile JIT and atomics on ARM
(e.g. [1]). If the problem doesn't appear when disabling JIT, then
you're probably seeing the same issue.
1: https://github.com/wingo/fibers/issues/83
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next prev parent reply other threads:[~2024-04-19 13:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-19 10:54 bug#70474: Possible bug with `atomic-box-swap!` on OSX/M3 (?!?!) Tony Garnock-Jones
2024-04-19 12:14 ` bug#70474: Also manifests on an M1 running 14.1.1 and with newer Guile versions Tony Garnock-Jones
2024-04-19 13:19 ` Christopher Baines [this message]
2024-04-19 20:46 ` bug#70474: [PATCH 1/2] Including the cast makes Apple clang 15.0.0 happy; without it, clang is sad Tony Garnock-Jones
2024-04-19 20:48 ` bug#70474: [PATCH 2/2] Replace aarch64 CAS and atomic-swap generated JIT code with CASAL and SWPAL instructions Tony Garnock-Jones
2024-04-22 7:52 ` bug#70474: Just adding DMB doesn't help Tony Garnock-Jones
2024-04-22 8:18 ` bug#70474: [PATCH] Move the spin loop target to the LDAXR instruction Tony Garnock-Jones
2024-04-22 11:23 ` Tony Garnock-Jones
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