from Hacker News

Green Tea Garbage Collector

by cirwin on 6/14/25, 4:10 AM with 11 comments

• by brianolson on 6/14/25, 11:03 AM

  "In select GC-heavy microbenchmarks ... we observed anywhere from a 10–50% reduction in GC CPU costs"

  - Yay!

  "The Go compiler benchmarks appear to inconsistently show a very slight regression (0.5%)"

  - Boo

  "Green Tea is available as an experiment at tip-of-tree and is planned as to be available as an opt-in experiment in Go 1.25"

  I definitely know some application code that spends 30% of CPU time in GC that needs to try this.

• by Imustaskforhelp on 6/14/25, 12:53 PM

  This is fantastic if I am reading it correctly. Making go even faster.

• by silisili on 6/14/25, 7:30 AM

  Well, I don't love that reported performance regressions are handwaved away as not the new gc, but doing something wrong or abnormal.

  Will wait for more real world cases showing substantial improvements, but existing(and possibly bad) code exists and it shouldn't be blamed for regressions.

• by rurban on 6/14/25, 6:23 PM

  So still an extremely slow mark & sweep with stop the world. No compaction, not moving.

  Mark & sweep is only really useful for external references, but golang has not many, much less than lisp.

• by rastignack on 6/15/25, 10:46 AM

  Austin Clements at it again…