Go 1.26's Green Tea GC Cuts Collector Overhead, Not Overall App Speed

Go 1.26, released on February 10, 2026, introduced a new garbage collection algorithm called Green Tea, enabled by default with no code changes required. The update targets a longstanding inefficiency where the collector wasted time chasing scattered object references across memory, causing frequent costly cache misses. Green Tea shifts the collector's work unit from individual objects to 8 KiB memory pages, shortening the work list and improving CPU cache utilization. Benchmarks show real performance gains, but these reflect reduced garbage collection overhead — not a blanket 40% speedup for all services. Applications with low GC pressure or bottlenecks elsewhere are unlikely to see significant improvements from the change.