The best place to start, if you haven't read it, is the documentation here: https://golang.org/ref/mem

For more detailed information on the garbage collector improvements and roadmap for 1.5 and beyond, this document is the Roadmap and discusses improvements being made including a maximum of 10 ms STW out of every 50 ms. https://docs.google.com/document/d/16Y4IsnNRCN43Mx0NZc5YXZLo...

edit: fixed incorrect link