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