From: Austin Clements <austin@google.com>
Date: Tue, 18 Jul 2017 15:21:15 +0000 (-0400)
Subject: runtime: move tSweepTerm capture closer to STW
X-Git-Tag: go1.9rc1~24
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=73d02735734e1ed1e4d1f5a7c534206596f3903a;p=gostls13.git

runtime: move tSweepTerm capture closer to STW

tSweepTerm and pauseStart are supposed to be when STW was triggered,
but right now they're captured a bit before STW. Move these down to
immediately before we trigger STW.

Fixes #19590.

Change-Id: Icd48a5c4d45c9b36187ff986e4f178b5064556c1
Reviewed-on: https://go-review.googlesource.com/49612
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
---

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 705fe697bb..111fa781e1 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -1248,13 +1248,13 @@ func gcStart(mode gcMode, trigger gcTrigger) {
 
 	gcResetMarkState()
 
-	now := nanotime()
 	work.stwprocs, work.maxprocs = gcprocs(), gomaxprocs
-	work.tSweepTerm = now
 	work.heap0 = atomic.Load64(&memstats.heap_live)
 	work.pauseNS = 0
 	work.mode = mode
 
+	now := nanotime()
+	work.tSweepTerm = now
 	work.pauseStart = now
 	systemstack(stopTheWorldWithSema)
 	// Finish sweep before we start concurrent scan.