runtime: dump scheduler state if GODEBUG=schedtrace is set
The schedtrace value sets dump period in milliseconds.
In default mode the trace looks as follows:
SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 [1 0 0 0]
SCHED 1001ms: gomaxprocs=4 idleprocs=3 threads=6 idlethreads=3 runqueue=0 [0 0 0 0]
SCHED 2008ms: gomaxprocs=4 idleprocs=1 threads=6 idlethreads=1 runqueue=0 [0 1 0 0]
If GODEBUG=scheddetail=1 is set as well, then the detailed trace is printed:
SCHED 0ms: gomaxprocs=4 idleprocs=0 threads=3 idlethreads=0 runqueue=0 singleproc=0 gcwaiting=1 mlocked=0 nmspinning=0 stopwait=0 sysmonwait=0
P0: status=3 tick=1 m=0 runqsize=1/128 gfreecnt=0
P1: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
P2: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
P3: status=3 tick=0 m=-1 runqsize=0/128 gfreecnt=0
M2: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1
M1: p=-1 curg=-1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=-1
M0: p=0 curg=1 mallocing=0 throwing=0 gcing=0 locks=1 dying=0 helpgc=0 spinning=0 lockedg=1
G1: status=2() m=0 lockedm=0
G2: status=1() m=-1 lockedm=-1
R=golang-dev, raggi, rsc
CC=golang-dev
https://golang.org/cl/11435044
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 89a42bb..c93a139 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -361,6 +361,7 @@
{
Lock;
+ int32 id;
uint32 status; // one of Pidle/Prunning/...
P* link;
uint32 schedtick; // incremented on every scheduler call
@@ -532,6 +533,8 @@
struct DebugVars
{
int32 gctrace;
+ int32 schedtrace;
+ int32 scheddetail;
};
/*
@@ -823,6 +826,7 @@
void runtime·breakpoint(void);
void runtime·gosched(void);
void runtime·gosched0(G*);
+void runtime·schedtrace(bool);
void runtime·park(void(*)(Lock*), Lock*, int8*);
void runtime·tsleep(int64, int8*);
M* runtime·newm(void);
