net: band-aid for windows network poller
Fixes performance of the current windows network poller
with the new scheduler.
Gives runtime a hint when GetQueuedCompletionStatus() will block.
Fixes #5068.
benchmark old ns/op new ns/op delta
BenchmarkTCP4Persistent 4004000 33906 -99.15%
BenchmarkTCP4Persistent-2 21790 17513 -19.63%
BenchmarkTCP4Persistent-4 44760 34270 -23.44%
BenchmarkTCP4Persistent-6 45280 43000 -5.04%
R=golang-dev, alex.brainman, coocood, rsc
CC=golang-dev
https://golang.org/cl/7612045
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 46c77e3..638acd4 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -238,6 +238,7 @@
bool ispanic;
bool issystem; // do not output in stack dump
bool isbackground; // ignore in deadlock detector
+ bool blockingsyscall; // hint that the next syscall will block
int8 raceignore; // ignore race detection events
M* m; // for debuggers, but offset not hard-coded
M* lockedm;
