unix: add Recvmmsg for linux by nickgarlis · Pull Request #276 · golang/sys

nickgarlis · 2026-05-21T07:09:43Z

Add a Recvmmsg wrapper that exposes the recvmmsg(2) system call,
allowing callers to receive multiple messages from a socket in a
single syscall.

ps and oobs are parallel slices of per-message payload and control
buffers, with vlen derived from len(ps). Each message uses a single
buffer rather than a scatter-gather vector, which should be sufficient
for the typical recvmmsg use case. The return values ns, oobns,
recvflags, and from are parallel slices of length n (the number of
messages received).

The wrapper is useful as-is and lets callers experiment with batch
receive patterns before a poller-integrated net package API is
designed.

Updates golang/go#45886

gopherbot · 2026-05-21T07:26:20Z

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gopherbot · 2026-05-21T07:41:07Z

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Patch Set 1:

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gopherbot · 2026-05-21T09:19:57Z

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Patch Set 3:

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gopherbot · 2026-05-21T10:19:33Z

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Patch Set 3:

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gopherbot · 2026-05-21T14:26:26Z

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gopherbot · 2026-05-21T14:43:04Z

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Patch Set 4:

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gopherbot · 2026-05-28T07:12:48Z

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gopherbot · 2026-05-30T11:46:17Z

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Patch Set 5:

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gopherbot · 2026-06-16T18:41:14Z

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gopherbot · 2026-06-16T20:11:12Z

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Patch Set 6:

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gopherbot · 2026-06-16T20:31:04Z

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Patch Set 6:

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gopherbot · 2026-06-16T20:31:05Z

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gopherbot · 2026-06-16T20:31:05Z

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gopherbot · 2026-06-16T20:51:08Z

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gopherbot · 2026-06-16T20:51:09Z

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Add a Recvmmsg wrapper that exposes the recvmmsg(2) system call, allowing callers to receive multiple messages from a socket in a single syscall. ps and oobs are parallel slices of per-message payload and control buffers, with vlen derived from len(ps). Each message uses a single buffer rather than a scatter-gather vector, which should be sufficient for the typical recvmmsg use case. The return values ns, oobns, recvflags, and from are parallel slices of length n (the number of messages received). This is a first step toward golang/go#45886. The wrapper is useful as-is and lets callers experiment with batch receive patterns before a poller-integrated net package API is designed.

Replace the initial Recvmmsg signature (parallel ps/oobs slices with multiple result slices) with the struct-based API discussed in golang/go#80434. RecvmmsgData holds both caller-provided input buffers (Data [][]byte for scatter/gather, OOB []byte) and per-message results (N, OOBN, Flags) written back on return. A []RecvmmsgData can be pre-allocated and reused across calls without per-call allocation. The sender address is stored directly in From RawSockaddrAny, which is zeroed before each call so struct reuse is safe; callers check From.Addr.Family != AF_UNSPEC to determine whether an address was filled in. AnyToSockaddr is exported for callers that need a parsed Sockaddr. Updates golang/go#80434

gopherbot · 2026-07-19T15:44:48Z

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nickgarlis mentioned this pull request May 26, 2026

WIP: conn_linux: add recvmmsg mdlayher/socket#30

Draft

nickgarlis force-pushed the add-recvmmsg branch from 871ed2d to 6fd57a0 Compare June 16, 2026 18:40

nickgarlis added 5 commits July 19, 2026 17:41

unix: reduce allocations for recvmmsg

90d5c28

unix: further reduce allocations for recvmmsg

3b8469f

unix: improve tests for recvmmsg

b4e9bde

nickgarlis force-pushed the add-recvmmsg branch from 6fd57a0 to f6292b0 Compare July 19, 2026 15:43

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