internal/runtime/atomic: add Cas128 primitive by mauri870 · Pull Request #79304 · golang/go

mauri870 · 2026-05-09T19:23:05Z

This is the initial work for the upcoming atomic.Uint64Pair.

amd64 uses LOCK CMPXCHG16B for v2+; arm64 uses an LDAXP/STLXP loop; all
other architectures fall back to a small fixed lock table keyed by the
16-byte-aligned pair address.

Specialization will come in at a later stage. There are no callers yet, so this is safe.

For #61236

This is the initial primitive for the upcoming atomic.Uint64Pair. amd64 uses LOCK CMPXCHG16B; arm64 uses an LDAXP/STLXP loop; all other architectures fall back to a small fixed lock table keyed by the 16-byte-aligned pair address. No GOAMD64 or GOARM64 feature gating for now. There are no callers yet, so this is safe.

gopherbot · 2026-05-09T19:39:20Z

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gopherbot · 2026-05-09T19:50:48Z

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gopherbot · 2026-05-09T20:25:32Z

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gopherbot · 2026-05-09T20:25:32Z

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Patch Set 2:

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gopherbot · 2026-05-09T20:36:56Z

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gopherbot · 2026-05-09T20:36:56Z

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Patch Set 2:

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gopherbot · 2026-05-09T20:36:57Z

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gopherbot · 2026-05-09T20:48:28Z

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gopherbot · 2026-05-09T21:34:15Z

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Patch Set 3: Commit-Queue+1

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gopherbot · 2026-05-09T21:45:32Z

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gopherbot · 2026-05-09T21:56:48Z

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gopherbot · 2026-05-09T21:56:48Z

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Patch Set 3:

This CL has failed the run. Reason:

Tryjob golang/try/gotip-windows-amd64 has failed with summary (view all results):

go on master (change 776400)

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gopherbot · 2026-05-09T21:56:49Z

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gopherbot · 2026-05-09T22:08:24Z

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Patch Set 3:

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gopherbot · 2026-05-09T22:42:35Z

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Patch Set 4:

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gopherbot · 2026-05-09T22:53:51Z

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Patch Set 4:

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gopherbot · 2026-05-09T23:28:14Z

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gopherbot · 2026-05-10T19:28:17Z

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gopherbot · 2026-05-10T19:39:58Z

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Patch Set 4:

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gopherbot · 2026-05-11T14:39:42Z

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Patch Set 5:

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gopherbot · 2026-05-11T14:39:42Z

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gopherbot · 2026-05-11T23:13:28Z

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gopherbot · 2026-05-11T23:50:36Z

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Patch Set 7: Commit-Queue+1

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gopherbot · 2026-05-11T23:50:36Z

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Patch Set 7:

Dry run: CV is trying the patch.

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gopherbot · 2026-05-12T00:27:51Z

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gopherbot · 2026-05-12T00:27:52Z

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gopherbot · 2026-05-12T00:27:52Z

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Patch Set 7: LUCI-TryBot-Result+1

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gopherbot · 2026-05-23T11:39:38Z

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gopherbot · 2026-05-25T21:58:53Z

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Patch Set 7: Code-Review+2

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gopherbot · 2026-05-27T11:41:33Z

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Patch Set 7:

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gopherbot · 2026-05-29T00:02:38Z

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gopherbot · 2026-05-29T00:15:56Z

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Patch Set 8: Commit-Queue+1

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gopherbot · 2026-05-29T00:15:57Z

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Patch Set 8:

Dry run: CV is trying the patch.

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gopherbot · 2026-05-29T00:29:46Z

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gopherbot · 2026-05-29T00:43:49Z

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Patch Set 8: -Commit-Queue

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gopherbot · 2026-05-29T00:43:50Z

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gopherbot · 2026-05-29T00:43:50Z

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gopherbot · 2026-05-29T17:14:17Z

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Patch Set 12: Auto-Submit+1 Code-Review+2 Commit-Queue+1

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gopherbot · 2026-05-29T17:14:18Z

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gopherbot · 2026-05-29T17:14:19Z

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gopherbot · 2026-05-29T17:30:58Z

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mauri870 self-assigned this May 9, 2026

fix test tripping up the race detector

12cbdb4

change signature to *[2]uint64

048049a

handle GOAMD64 for CMPXCHG16B

b9b6a71

mauri870 force-pushed the atomic-cas128 branch from 49258c2 to b9b6a71 Compare May 11, 2026 23:09

hbrooks mentioned this pull request May 28, 2026

internal/runtime/atomic: add Cas128 primitive ellipsis-dev-test/go#8

Open

mauri870 added 2 commits May 28, 2026 20:54

sync

2d75cef

Merge remote-tracking branch 'upstream/master' into atomic-cas128

ad4be03

mauri870 force-pushed the atomic-cas128 branch from 7c8f710 to b6c80ff Compare May 29, 2026 00:22

move locktab.go to native.go

07387b6

mauri870 force-pushed the atomic-cas128 branch from b6c80ff to 07387b6 Compare May 29, 2026 01:05

mauri870 added 2 commits May 28, 2026 22:19

sync

65775dc

unsync

ff23014

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