tree 1eaaf5f4310de7fd1af5df6107688a6df936e00b
parent 12ea156365b44222df108bc48462046bc9f727ea
author Michael Anthony Knyszek <mknyszek@google.com> 1631830465 +0000
committer Michael Knyszek <mknyszek@google.com> 1647883029 +0000

design: update gc-pacer-redesign and remove inaccuracies

This change updates the GC pacer redesign design document to remove a
few inaccuracies and update two points that became apparent after
experimentation.

Firstly, the inaccuracies were mostly around what was ignored. For
instance, goroutines already donate their debt or credit back to the
global pool on death.

Secondly, the definition of the heap goal included S_n and G_n twice
erroneously. It was written that way with _overall_ GC-work-related
memory used in mind, but the definition is _just_ for heap memory.

Lastly, it turns out that the current pacer does (in its own indirect
way) account for idle priority GC in some way, and not accounting for it
in the new pacer leads to a performance regression. This change adds a
section describing how to account for it.

For golang/go#44167.

Change-Id: I396bbcb87fc3acd84584b10769e31d7da699fdb9
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/350429
Reviewed-by: Michael Knyszek <mknyszek@google.com>