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runtime: convert g.waitreason from string to uint8

Every time I poke at #14921, the g.waitreason string
pointer writes show up.

They're not particularly important performance-wise,
but it'd be nice to clear the noise away.

And it does open up a few extra bytes in the g struct
for some future use.

Change-Id: I7ffbd52fbc2a286931a2218038fda52ed6473cc9
Reviewed-on: https://go-review.googlesource.com/99078
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Josh Bleecher Snyder 2018-03-06 21:28:24 -08:00
parent 025134b0d1
commit 4eea887fd4
15 changed files with 114 additions and 47 deletions

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@ -142,7 +142,7 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool {
if !block {
return false
}
gopark(nil, nil, "chan send (nil chan)", traceEvGoStop, 2)
gopark(nil, nil, waitReasonChanSendNilChan, traceEvGoStop, 2)
throw("unreachable")
}
@ -231,7 +231,7 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool {
gp.waiting = mysg
gp.param = nil
c.sendq.enqueue(mysg)
goparkunlock(&c.lock, "chan send", traceEvGoBlockSend, 3)
goparkunlock(&c.lock, waitReasonChanSend, traceEvGoBlockSend, 3)
// someone woke us up.
if mysg != gp.waiting {
@ -426,7 +426,7 @@ func chanrecv(c *hchan, ep unsafe.Pointer, block bool) (selected, received bool)
if !block {
return
}
gopark(nil, nil, "chan receive (nil chan)", traceEvGoStop, 2)
gopark(nil, nil, waitReasonChanReceiveNilChan, traceEvGoStop, 2)
throw("unreachable")
}
@ -517,7 +517,7 @@ func chanrecv(c *hchan, ep unsafe.Pointer, block bool) (selected, received bool)
mysg.c = c
gp.param = nil
c.recvq.enqueue(mysg)
goparkunlock(&c.lock, "chan receive", traceEvGoBlockRecv, 3)
goparkunlock(&c.lock, waitReasonChanReceive, traceEvGoBlockRecv, 3)
// someone woke us up
if mysg != gp.waiting {

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@ -349,7 +349,7 @@ func dumpgoroutine(gp *g) {
dumpbool(isSystemGoroutine(gp))
dumpbool(false) // isbackground
dumpint(uint64(gp.waitsince))
dumpstr(gp.waitreason)
dumpstr(gp.waitreason.String())
dumpint(uint64(uintptr(gp.sched.ctxt)))
dumpint(uint64(uintptr(unsafe.Pointer(gp.m))))
dumpint(uint64(uintptr(unsafe.Pointer(gp._defer))))
@ -658,7 +658,7 @@ func mdump() {
func writeheapdump_m(fd uintptr) {
_g_ := getg()
casgstatus(_g_.m.curg, _Grunning, _Gwaiting)
_g_.waitreason = "dumping heap"
_g_.waitreason = waitReasonDumpingHeap
// Update stats so we can dump them.
// As a side effect, flushes all the MCaches so the MSpan.freelist

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@ -172,7 +172,7 @@ func runfinq() {
gp := getg()
fing = gp
fingwait = true
goparkunlock(&finlock, "finalizer wait", traceEvGoBlock, 1)
goparkunlock(&finlock, waitReasonFinalizerWait, traceEvGoBlock, 1)
continue
}
unlock(&finlock)

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@ -241,7 +241,7 @@ func setGCPercent(in int32) (out int32) {
gp := getg()
gp.schedlink = work.sweepWaiters.head
work.sweepWaiters.head.set(gp)
goparkunlock(&work.sweepWaiters.lock, "wait for GC cycle", traceEvGoBlock, 1)
goparkunlock(&work.sweepWaiters.lock, waitReasonWaitForGCCycle, traceEvGoBlock, 1)
} else {
// GC isn't active.
unlock(&work.sweepWaiters.lock)
@ -1100,7 +1100,7 @@ func GC() {
// termination of cycle N complete.
gp.schedlink = work.sweepWaiters.head
work.sweepWaiters.head.set(gp)
goparkunlock(&work.sweepWaiters.lock, "wait for GC cycle", traceEvGoBlock, 1)
goparkunlock(&work.sweepWaiters.lock, waitReasonWaitForGCCycle, traceEvGoBlock, 1)
} else {
// We're in sweep N already.
unlock(&work.sweepWaiters.lock)
@ -1116,7 +1116,7 @@ func GC() {
if gcphase == _GCmark && atomic.Load(&work.cycles) == n+1 {
gp.schedlink = work.sweepWaiters.head
work.sweepWaiters.head.set(gp)
goparkunlock(&work.sweepWaiters.lock, "wait for GC cycle", traceEvGoBlock, 1)
goparkunlock(&work.sweepWaiters.lock, waitReasonWaitForGCCycle, traceEvGoBlock, 1)
} else {
unlock(&work.sweepWaiters.lock)
}
@ -1530,7 +1530,7 @@ func gcMarkTermination(nextTriggerRatio float64) {
_g_.m.traceback = 2
gp := _g_.m.curg
casgstatus(gp, _Grunning, _Gwaiting)
gp.waitreason = "garbage collection"
gp.waitreason = waitReasonGarbageCollection
// Run gc on the g0 stack. We do this so that the g stack
// we're currently running on will no longer change. Cuts
@ -1799,7 +1799,7 @@ func gcBgMarkWorker(_p_ *p) {
}
}
return true
}, unsafe.Pointer(park), "GC worker (idle)", traceEvGoBlock, 0)
}, unsafe.Pointer(park), waitReasonGCWorkerIdle, traceEvGoBlock, 0)
// Loop until the P dies and disassociates this
// worker (the P may later be reused, in which case

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@ -251,7 +251,7 @@ func markroot(gcw *gcWork, i uint32) {
selfScan := gp == userG && readgstatus(userG) == _Grunning
if selfScan {
casgstatus(userG, _Grunning, _Gwaiting)
userG.waitreason = "garbage collection scan"
userG.waitreason = waitReasonGarbageCollectionScan
}
// TODO: scang blocks until gp's stack has
@ -549,7 +549,7 @@ func gcAssistAlloc1(gp *g, scanWork int64) {
// gcDrainN requires the caller to be preemptible.
casgstatus(gp, _Grunning, _Gwaiting)
gp.waitreason = "GC assist marking"
gp.waitreason = waitReasonGCAssistMarking
// drain own cached work first in the hopes that it
// will be more cache friendly.
@ -648,7 +648,7 @@ func gcParkAssist() bool {
return false
}
// Park.
goparkunlock(&work.assistQueue.lock, "GC assist wait", traceEvGoBlockGC, 2)
goparkunlock(&work.assistQueue.lock, waitReasonGCAssistWait, traceEvGoBlockGC, 2)
return true
}

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@ -49,7 +49,7 @@ func bgsweep(c chan int) {
lock(&sweep.lock)
sweep.parked = true
c <- 1
goparkunlock(&sweep.lock, "GC sweep wait", traceEvGoBlock, 1)
goparkunlock(&sweep.lock, waitReasonGCSweepWait, traceEvGoBlock, 1)
for {
for gosweepone() != ^uintptr(0) {
@ -68,7 +68,7 @@ func bgsweep(c chan int) {
continue
}
sweep.parked = true
goparkunlock(&sweep.lock, "GC sweep wait", traceEvGoBlock, 1)
goparkunlock(&sweep.lock, waitReasonGCSweepWait, traceEvGoBlock, 1)
}
}

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@ -363,7 +363,7 @@ func netpollblock(pd *pollDesc, mode int32, waitio bool) bool {
// this is necessary because runtime_pollUnblock/runtime_pollSetDeadline/deadlineimpl
// do the opposite: store to closing/rd/wd, membarrier, load of rg/wg
if waitio || netpollcheckerr(pd, mode) == 0 {
gopark(netpollblockcommit, unsafe.Pointer(gpp), "IO wait", traceEvGoBlockNet, 5)
gopark(netpollblockcommit, unsafe.Pointer(gpp), waitReasonIOWait, traceEvGoBlockNet, 5)
}
// be careful to not lose concurrent READY notification
old := atomic.Xchguintptr(gpp, 0)

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@ -214,7 +214,7 @@ func main() {
}
}
if atomic.Load(&panicking) != 0 {
gopark(nil, nil, "panicwait", traceEvGoStop, 1)
gopark(nil, nil, waitReasonPanicWait, traceEvGoStop, 1)
}
exit(0)
@ -245,7 +245,7 @@ func forcegchelper() {
throw("forcegc: phase error")
}
atomic.Store(&forcegc.idle, 1)
goparkunlock(&forcegc.lock, "force gc (idle)", traceEvGoBlock, 1)
goparkunlock(&forcegc.lock, waitReasonForceGGIdle, traceEvGoBlock, 1)
// this goroutine is explicitly resumed by sysmon
if debug.gctrace > 0 {
println("GC forced")
@ -274,7 +274,11 @@ func goschedguarded() {
// If unlockf returns false, the goroutine is resumed.
// unlockf must not access this G's stack, as it may be moved between
// the call to gopark and the call to unlockf.
func gopark(unlockf func(*g, unsafe.Pointer) bool, lock unsafe.Pointer, reason string, traceEv byte, traceskip int) {
// Reason explains why the goroutine has been parked.
// It is displayed in stack traces and heap dumps.
// Reasons should be unique and descriptive.
// Do not re-use reasons, add new ones.
func gopark(unlockf func(*g, unsafe.Pointer) bool, lock unsafe.Pointer, reason waitReason, traceEv byte, traceskip int) {
mp := acquirem()
gp := mp.curg
status := readgstatus(gp)
@ -293,7 +297,7 @@ func gopark(unlockf func(*g, unsafe.Pointer) bool, lock unsafe.Pointer, reason s
// Puts the current goroutine into a waiting state and unlocks the lock.
// The goroutine can be made runnable again by calling goready(gp).
func goparkunlock(lock *mutex, reason string, traceEv byte, traceskip int) {
func goparkunlock(lock *mutex, reason waitReason, traceEv byte, traceskip int) {
gopark(parkunlock_c, unsafe.Pointer(lock), reason, traceEv, traceskip)
}
@ -2667,7 +2671,7 @@ func goexit0(gp *g) {
gp._defer = nil // should be true already but just in case.
gp._panic = nil // non-nil for Goexit during panic. points at stack-allocated data.
gp.writebuf = nil
gp.waitreason = ""
gp.waitreason = 0
gp.param = nil
gp.labels = nil
gp.timer = nil
@ -4493,7 +4497,7 @@ func schedtrace(detailed bool) {
if lockedm != nil {
id2 = lockedm.id
}
print(" G", gp.goid, ": status=", readgstatus(gp), "(", gp.waitreason, ") m=", id1, " lockedm=", id2, "\n")
print(" G", gp.goid, ": status=", readgstatus(gp), "(", gp.waitreason.String(), ") m=", id1, " lockedm=", id2, "\n")
}
unlock(&allglock)
unlock(&sched.lock)

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@ -358,20 +358,20 @@ type g struct {
atomicstatus uint32
stackLock uint32 // sigprof/scang lock; TODO: fold in to atomicstatus
goid int64
waitsince int64 // approx time when the g become blocked
waitreason string // if status==Gwaiting
schedlink guintptr
preempt bool // preemption signal, duplicates stackguard0 = stackpreempt
paniconfault bool // panic (instead of crash) on unexpected fault address
preemptscan bool // preempted g does scan for gc
gcscandone bool // g has scanned stack; protected by _Gscan bit in status
gcscanvalid bool // false at start of gc cycle, true if G has not run since last scan; TODO: remove?
throwsplit bool // must not split stack
raceignore int8 // ignore race detection events
sysblocktraced bool // StartTrace has emitted EvGoInSyscall about this goroutine
sysexitticks int64 // cputicks when syscall has returned (for tracing)
traceseq uint64 // trace event sequencer
tracelastp puintptr // last P emitted an event for this goroutine
waitsince int64 // approx time when the g become blocked
waitreason waitReason // if status==Gwaiting
preempt bool // preemption signal, duplicates stackguard0 = stackpreempt
paniconfault bool // panic (instead of crash) on unexpected fault address
preemptscan bool // preempted g does scan for gc
gcscandone bool // g has scanned stack; protected by _Gscan bit in status
gcscanvalid bool // false at start of gc cycle, true if G has not run since last scan; TODO: remove?
throwsplit bool // must not split stack
raceignore int8 // ignore race detection events
sysblocktraced bool // StartTrace has emitted EvGoInSyscall about this goroutine
sysexitticks int64 // cputicks when syscall has returned (for tracing)
traceseq uint64 // trace event sequencer
tracelastp puintptr // last P emitted an event for this goroutine
lockedm muintptr
sig uint32
writebuf []byte
@ -752,6 +752,69 @@ const (
// The maximum number of frames we print for a traceback
const _TracebackMaxFrames = 100
// A waitReason explains why a goroutine has been stopped.
// See gopark. Do not re-use waitReasons, add new ones.
type waitReason uint8
const (
waitReasonZero waitReason = iota // ""
waitReasonGCAssistMarking // "GC assist marking"
waitReasonIOWait // "IO wait"
waitReasonChanReceiveNilChan // "chan receive (nil chan)"
waitReasonChanSendNilChan // "chan send (nil chan)"
waitReasonDumpingHeap // "dumping heap"
waitReasonGarbageCollection // "garbage collection"
waitReasonGarbageCollectionScan // "garbage collection scan"
waitReasonPanicWait // "panicwait"
waitReasonSelect // "select"
waitReasonSelectNoCases // "select (no cases)"
waitReasonGCAssistWait // "GC assist wait"
waitReasonGCSweepWait // "GC sweep wait"
waitReasonChanReceive // "chan receive"
waitReasonChanSend // "chan send"
waitReasonFinalizerWait // "finalizer wait"
waitReasonForceGGIdle // "force gc (idle)"
waitReasonSemacquire // "semacquire"
waitReasonSleep // "sleep"
waitReasonTimerGoroutineIdle // "timer goroutine (idle)"
waitReasonTraceReaderBlocked // "trace reader (blocked)"
waitReasonWaitForGCCycle // "wait for GC cycle"
waitReasonGCWorkerIdle // "GC worker (idle)"
)
var waitReasonStrings = [...]string{
waitReasonZero: "",
waitReasonGCAssistMarking: "GC assist marking",
waitReasonIOWait: "IO wait",
waitReasonChanReceiveNilChan: "chan receive (nil chan)",
waitReasonChanSendNilChan: "chan send (nil chan)",
waitReasonDumpingHeap: "dumping heap",
waitReasonGarbageCollection: "garbage collection",
waitReasonGarbageCollectionScan: "garbage collection scan",
waitReasonPanicWait: "panicwait",
waitReasonSelect: "select",
waitReasonSelectNoCases: "select (no cases)",
waitReasonGCAssistWait: "GC assist wait",
waitReasonGCSweepWait: "GC sweep wait",
waitReasonChanReceive: "chan receive",
waitReasonChanSend: "chan send",
waitReasonFinalizerWait: "finalizer wait",
waitReasonForceGGIdle: "force gc (idle)",
waitReasonSemacquire: "semacquire",
waitReasonSleep: "sleep",
waitReasonTimerGoroutineIdle: "timer goroutine (idle)",
waitReasonTraceReaderBlocked: "trace reader (blocked)",
waitReasonWaitForGCCycle: "wait for GC cycle",
waitReasonGCWorkerIdle: "GC worker (idle)",
}
func (w waitReason) String() string {
if w < 0 || w >= waitReason(len(waitReasonStrings)) {
return "unknown wait reason"
}
return waitReasonStrings[w]
}
var (
allglen uintptr
allm *m

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@ -189,7 +189,7 @@ func selparkcommit(gp *g, _ unsafe.Pointer) bool {
}
func block() {
gopark(nil, nil, "select (no cases)", traceEvGoStop, 1) // forever
gopark(nil, nil, waitReasonSelectNoCases, traceEvGoStop, 1) // forever
}
// selectgo implements the select statement.
@ -389,7 +389,7 @@ loop:
// wait for someone to wake us up
gp.param = nil
gopark(selparkcommit, nil, "select", traceEvGoBlockSelect, 1)
gopark(selparkcommit, nil, waitReasonSelect, traceEvGoBlockSelect, 1)
sellock(scases, lockorder)

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@ -141,7 +141,7 @@ func semacquire1(addr *uint32, lifo bool, profile semaProfileFlags) {
// Any semrelease after the cansemacquire knows we're waiting
// (we set nwait above), so go to sleep.
root.queue(addr, s, lifo)
goparkunlock(&root.lock, "semacquire", traceEvGoBlockSync, 4)
goparkunlock(&root.lock, waitReasonSemacquire, traceEvGoBlockSync, 4)
if s.ticket != 0 || cansemacquire(addr) {
break
}
@ -507,7 +507,7 @@ func notifyListWait(l *notifyList, t uint32) {
l.tail.next = s
}
l.tail = s
goparkunlock(&l.lock, "semacquire", traceEvGoBlockCond, 3)
goparkunlock(&l.lock, waitReasonSemacquire, traceEvGoBlockCond, 3)
if t0 != 0 {
blockevent(s.releasetime-t0, 2)
}

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@ -23,7 +23,7 @@ func TestSizeof(t *testing.T) {
_32bit uintptr // size on 32bit platforms
_64bit uintptr // size on 64bit platforms
}{
{runtime.G{}, 216, 376}, // g, but exported for testing
{runtime.G{}, 212, 368}, // g, but exported for testing
}
for _, tt := range tests {

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@ -99,7 +99,7 @@ func timeSleep(ns int64) {
tb := t.assignBucket()
lock(&tb.lock)
tb.addtimerLocked(t)
goparkunlock(&tb.lock, "sleep", traceEvGoSleep, 2)
goparkunlock(&tb.lock, waitReasonSleep, traceEvGoSleep, 2)
}
// startTimer adds t to the timer heap.
@ -250,7 +250,7 @@ func timerproc(tb *timersBucket) {
if delta < 0 || faketime > 0 {
// No timers left - put goroutine to sleep.
tb.rescheduling = true
goparkunlock(&tb.lock, "timer goroutine (idle)", traceEvGoBlock, 1)
goparkunlock(&tb.lock, waitReasonTimerGoroutineIdle, traceEvGoBlock, 1)
continue
}
// At least one timer pending. Sleep until then.

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@ -392,7 +392,7 @@ func ReadTrace() []byte {
// Wait for new data.
if trace.fullHead == 0 && !trace.shutdown {
trace.reader.set(getg())
goparkunlock(&trace.lock, "trace reader (blocked)", traceEvGoBlock, 2)
goparkunlock(&trace.lock, waitReasonTraceReaderBlocked, traceEvGoBlock, 2)
lock(&trace.lock)
}
// Write a buffer.

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@ -827,8 +827,8 @@ func goroutineheader(gp *g) {
}
// Override.
if gpstatus == _Gwaiting && gp.waitreason != "" {
status = gp.waitreason
if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero {
status = gp.waitreason.String()
}
// approx time the G is blocked, in minutes