From 88c24de8b53dbd68905554a2a3b72a0eeda78a16 Mon Sep 17 00:00:00 2001 From: Michael Anthony Knyszek Date: Mon, 1 Dec 2025 18:07:50 +0000 Subject: [PATCH] doc/next: add section for Green Tea Change-Id: I420e8d673e5d34d1b09c02b8bc84b890da42e320 Reviewed-on: https://go-review.googlesource.com/c/go/+/725662 Reviewed-by: Michael Pratt Auto-Submit: Michael Knyszek LUCI-TryBot-Result: Go LUCI --- doc/next/4-runtime.md | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/doc/next/4-runtime.md b/doc/next/4-runtime.md index 1f8e445e0b..d8fcb8f9ee 100644 --- a/doc/next/4-runtime.md +++ b/doc/next/4-runtime.md @@ -1 +1,22 @@ ## Runtime {#runtime} + +### New garbage collector + +The Green Tea garbage collector, previously available as an experiment in +Go 1.25, is now enabled by default after incorporating feedback. + +This garbage collector’s design improves the performance of marking and +scanning small objects through better locality and CPU scalability. +Benchmark result vary, but we expect somewhere between a 10—40% reduction +in garbage collection overhead in real-world programs that heavily use the +garbage collector. +Further improvements, on the order of 10% in garbage collection overhead, +are expected when running on newer amd64-based CPU platforms (Intel Ice +Lake or AMD Zen 4 and newer), as the garbage collector now leverages +vector instructions for scanning small objects when possible. + +The new garbage collector may be disabled by setting +`GOEXPERIMENT=nogreenteagc` at build time. +This opt-out setting is expected to be removed in Go 1.27. +If you disable the new garbage collector for any reason related to its +performance or behavior, please [file an issue](/issue/new). -- 2.52.0