1 files changed, 3 insertions, 86 deletions

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 910918f4b4..db6f908e8c 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -663,59 +663,6 @@ func ready(gp *g, traceskip int, next bool) {
 	}
 }
 
-func gcprocs() int32 {
-	// Figure out how many CPUs to use during GC.
-	// Limited by gomaxprocs, number of actual CPUs, and MaxGcproc.
-	lock(&sched.lock)
-	n := gomaxprocs
-	if n > ncpu {
-		n = ncpu
-	}
-	if n > _MaxGcproc {
-		n = _MaxGcproc
-	}
-	if n > sched.nmidle+1 { // one M is currently running
-		n = sched.nmidle + 1
-	}
-	unlock(&sched.lock)
-	return n
-}
-
-func needaddgcproc() bool {
-	lock(&sched.lock)
-	n := gomaxprocs
-	if n > ncpu {
-		n = ncpu
-	}
-	if n > _MaxGcproc {
-		n = _MaxGcproc
-	}
-	n -= sched.nmidle + 1 // one M is currently running
-	unlock(&sched.lock)
-	return n > 0
-}
-
-func helpgc(nproc int32) {
-	_g_ := getg()
-	lock(&sched.lock)
-	pos := 0
-	for n := int32(1); n < nproc; n++ { // one M is currently running
-		if allp[pos].mcache == _g_.m.mcache {
-			pos++
-		}
-		mp := mget()
-		if mp == nil {
-			throw("gcprocs inconsistency")
-		}
-		mp.helpgc = n
-		mp.p.set(allp[pos])
-		mp.mcache = allp[pos].mcache
-		pos++
-		notewakeup(&mp.park)
-	}
-	unlock(&sched.lock)
-}
-
 // freezeStopWait is a large value that freezetheworld sets
 // sched.stopwait to in order to request that all Gs permanently stop.
 const freezeStopWait = 0x7fffffff
@@ -1132,11 +1079,6 @@ func stopTheWorldWithSema() {
 	}
 }
 
-func mhelpgc() {
-	_g_ := getg()
-	_g_.m.helpgc = -1
-}
-
 func startTheWorldWithSema(emitTraceEvent bool) int64 {
 	_g_ := getg()
 
@@ -1145,7 +1087,6 @@ func startTheWorldWithSema(emitTraceEvent bool) int64 {
 		list := netpoll(false) // non-blocking
 		injectglist(&list)
 	}
-	add := needaddgcproc()
 	lock(&sched.lock)
 
 	procs := gomaxprocs
@@ -1175,7 +1116,6 @@ func startTheWorldWithSema(emitTraceEvent bool) int64 {
 		} else {
 			// Start M to run P.  Do not start another M below.
 			newm(nil, p)
-			add = false
 		}
 	}
 
@@ -1192,16 +1132,6 @@ func startTheWorldWithSema(emitTraceEvent bool) int64 {
 		wakep()
 	}
 
-	if add {
-		// If GC could have used another helper proc, start one now,
-		// in the hope that it will be available next time.
-		// It would have been even better to start it before the collection,
-		// but doing so requires allocating memory, so it's tricky to
-		// coordinate. This lazy approach works out in practice:
-		// we don't mind if the first couple gc rounds don't have quite
-		// the maximum number of procs.
-		newm(mhelpgc, nil)
-	}
 	_g_.m.locks--
 	if _g_.m.locks == 0 && _g_.preempt { // restore the preemption request in case we've cleared it in newstack
 		_g_.stackguard0 = stackPreempt
@@ -1276,10 +1206,7 @@ func mstart1() {
 		fn()
 	}
 
-	if _g_.m.helpgc != 0 {
-		_g_.m.helpgc = 0
-		stopm()
-	} else if _g_.m != &m0 {
+	if _g_.m != &m0 {
 		acquirep(_g_.m.nextp.ptr())
 		_g_.m.nextp = 0
 	}
@@ -2003,21 +1930,11 @@ func stopm() {
 		throw("stopm spinning")
 	}
 
-retry:
 	lock(&sched.lock)
 	mput(_g_.m)
 	unlock(&sched.lock)
 	notesleep(&_g_.m.park)
 	noteclear(&_g_.m.park)
-	if _g_.m.helpgc != 0 {
-		// helpgc() set _g_.m.p and _g_.m.mcache, so we have a P.
-		gchelper()
-		// Undo the effects of helpgc().
-		_g_.m.helpgc = 0
-		_g_.m.mcache = nil
-		_g_.m.p = 0
-		goto retry
-	}
 	acquirep(_g_.m.nextp.ptr())
 	_g_.m.nextp = 0
 }
@@ -3857,7 +3774,7 @@ func sigprof(pc, sp, lr uintptr, gp *g, mp *m) {
 				pc = funcPC(_ExternalCode) + sys.PCQuantum
 			}
 			stk[0] = pc
-			if mp.preemptoff != "" || mp.helpgc != 0 {
+			if mp.preemptoff != "" {
 				stk[1] = funcPC(_GC) + sys.PCQuantum
 			} else {
 				stk[1] = funcPC(_System) + sys.PCQuantum
@@ -4634,7 +4551,7 @@ func schedtrace(detailed bool) {
 		if lockedg != nil {
 			id3 = lockedg.goid
 		}
-		print("  M", mp.id, ": p=", id1, " curg=", id2, " mallocing=", mp.mallocing, " throwing=", mp.throwing, " preemptoff=", mp.preemptoff, ""+" locks=", mp.locks, " dying=", mp.dying, " helpgc=", mp.helpgc, " spinning=", mp.spinning, " blocked=", mp.blocked, " lockedg=", id3, "\n")
+		print("  M", mp.id, ": p=", id1, " curg=", id2, " mallocing=", mp.mallocing, " throwing=", mp.throwing, " preemptoff=", mp.preemptoff, ""+" locks=", mp.locks, " dying=", mp.dying, " spinning=", mp.spinning, " blocked=", mp.blocked, " lockedg=", id3, "\n")
 	}
 
 	lock(&allglock)