Golang atomic.LoadUint32函數代碼示例

func TestRefreshNoChange(t *testing.T) {
	var (
		addr      = &net.SRV{Target: "my-target", Port: 5678}
		addrs     = []*net.SRV{addr}
		name      = "my-name"
		ticker    = time.NewTicker(time.Second)
		lookups   = uint32(0)
		lookupSRV = func(string, string, string) (string, []*net.SRV, error) {
			atomic.AddUint32(&lookups, 1)
			return "", addrs, nil
		}
		e       = func(context.Context, interface{}) (interface{}, error) { return struct{}{}, nil }
		factory = func(string) (endpoint.Endpoint, io.Closer, error) { return e, nil, nil }
		logger  = log.NewNopLogger()
	)

	ticker.Stop()
	tickc := make(chan time.Time)
	ticker.C = tickc

	p := NewPublisherDetailed(name, ticker, lookupSRV, factory, logger)
	defer p.Stop()

	if want, have := uint32(1), atomic.LoadUint32(&lookups); want != have {
		t.Errorf("want %d, have %d", want, have)
	}

	tickc <- time.Now()

	if want, have := uint32(2), atomic.LoadUint32(&lookups); want != have {
		t.Errorf("want %d, have %d", want, have)
	}
}

func testThrottling(t *testing.T, protocol int) {
	// Create a long block chain to download and the tester
	targetBlocks := 8 * blockCacheLimit
	hashes, blocks := makeChain(targetBlocks, 0, genesis)

	tester := newTester()
	tester.newPeer("peer", protocol, hashes, blocks)

	// Wrap the importer to allow stepping
	blocked, proceed := uint32(0), make(chan struct{})
	tester.downloader.chainInsertHook = func(blocks []*Block) {
		atomic.StoreUint32(&blocked, uint32(len(blocks)))
		<-proceed
	}
	// Start a synchronisation concurrently
	errc := make(chan error)
	go func() {
		errc <- tester.sync("peer", nil)
	}()
	// Iteratively take some blocks, always checking the retrieval count
	for {
		// Check the retrieval count synchronously (! reason for this ugly block)
		tester.lock.RLock()
		retrieved := len(tester.ownBlocks)
		tester.lock.RUnlock()
		if retrieved >= targetBlocks+1 {
			break
		}
		// Wait a bit for sync to throttle itself
		var cached int
		for start := time.Now(); time.Since(start) < time.Second; {
			time.Sleep(25 * time.Millisecond)

			tester.downloader.queue.lock.RLock()
			cached = len(tester.downloader.queue.blockPool)
			tester.downloader.queue.lock.RUnlock()

			if cached == blockCacheLimit || len(tester.ownBlocks)+cached+int(atomic.LoadUint32(&blocked)) == targetBlocks+1 {
				break
			}
		}
		// Make sure we filled up the cache, then exhaust it
		time.Sleep(25 * time.Millisecond) // give it a chance to screw up
		if cached != blockCacheLimit && len(tester.ownBlocks)+cached+int(atomic.LoadUint32(&blocked)) != targetBlocks+1 {
			t.Fatalf("block count mismatch: have %v, want %v (owned %v, target %v)", cached, blockCacheLimit, len(tester.ownBlocks), targetBlocks+1)
		}
		// Permit the blocked blocks to import
		if atomic.LoadUint32(&blocked) > 0 {
			atomic.StoreUint32(&blocked, uint32(0))
			proceed <- struct{}{}
		}
	}
	// Check that we haven't pulled more blocks than available
	if len(tester.ownBlocks) > targetBlocks+1 {
		t.Fatalf("target block count mismatch: have %v, want %v", len(tester.ownBlocks), targetBlocks+1)
	}
	if err := <-errc; err != nil {
		t.Fatalf("block synchronization failed: %v", err)
	}
}

// Release the peer connection certifying that we are done with it.
func (p *PeerResponse) Release() {
	ref := atomic.LoadUint32(&p.peer.refCount)
	// Decrement ownership
	for ref > 0 && atomic.CompareAndSwapUint32(&p.peer.refCount, ref, ref-1) == false {
		ref = atomic.LoadUint32(&p.peer.refCount)
	}
}

// Test that Pool does not hold pointers to previously cached
// resources
func TestPoolGC(t *testing.T) {
	var p Pool
	var fin uint32
	const N = 100
	for i := 0; i < N; i++ {
		v := new(int)
		runtime.SetFinalizer(v, func(vv *int) {
			atomic.AddUint32(&fin, 1)
		})
		p.Put(v)
	}
	for i := 0; i < N; i++ {
		p.Get()
	}
	for i := 0; i < 5; i++ {
		runtime.GC()
		time.Sleep(time.Millisecond)
		// 2 pointers can remain on stack or elsewhere
		if atomic.LoadUint32(&fin) >= N-2 {
			return
		}
	}
	t.Fatalf("only %v out of %v resources are finalized",
		atomic.LoadUint32(&fin), N)
}

// save stat
func (p *Whisper) doCheckpoint() {
	updateOperations := atomic.LoadUint32(&p.updateOperations)
	commitedPoints := atomic.LoadUint32(&p.commitedPoints)
	atomic.AddUint32(&p.updateOperations, -updateOperations)
	atomic.AddUint32(&p.commitedPoints, -commitedPoints)

	created := atomic.LoadUint32(&p.created)
	atomic.AddUint32(&p.created, -created)

	logrus.WithFields(logrus.Fields{
		"updateOperations": int(updateOperations),
		"commitedPoints":   int(commitedPoints),
		"created":          int(created),
	}).Info("[persister] doCheckpoint()")

	p.Stat("updateOperations", float64(updateOperations))
	p.Stat("commitedPoints", float64(commitedPoints))
	if updateOperations > 0 {
		p.Stat("pointsPerUpdate", float64(commitedPoints)/float64(updateOperations))
	} else {
		p.Stat("pointsPerUpdate", 0.0)
	}

	p.Stat("created", float64(created))

}

func (c *LRUCache) gc() {
	time.Sleep(30 * time.Second)
	ms := new(runtime.MemStats)
	var gcFactor uint32 = 0
	for {
		runtime.ReadMemStats(ms)

		// update gc factor
		if ms.HeapAlloc < c.configuration.size {
			// stop gc only when cache < 90% of cache limit.
			if gcFactor != 0 && ms.HeapAlloc < uint64(0.9*float64(c.configuration.size)) {
				c.setGcFactor(0)
				gcFactor = 0
			}
		} else {
			if gcFactor == 0 || gcFactor != atomic.LoadUint32(&c.gcFactorCfg) {
				gcFactor = atomic.LoadUint32(&c.gcFactorCfg)
				c.setGcFactor(gcFactor)
			}
		}

		// notify gcing
		if gcFactor != 0 && c.configuration.callback != nil {
			c.configuration.callback()
		}

		time.Sleep(10 * time.Second)
	}
}

func (s *IDGenerator) GetStream() (int, bool) {
	// based closely on the java-driver stream ID generator
	// avoid false sharing subsequent requests.
	offset := atomic.LoadUint32(&s.offset)
	for !atomic.CompareAndSwapUint32(&s.offset, offset, (offset+1)%s.numBuckets) {
		offset = atomic.LoadUint32(&s.offset)
	}
	offset = (offset + 1) % s.numBuckets

	for i := uint32(0); i < s.numBuckets; i++ {
		pos := int((i + offset) % s.numBuckets)

		bucket := atomic.LoadUint64(&s.streams[pos])
		if bucket == math.MaxUint64 {
			// all streams in use
			continue
		}

		for j := 0; j < bucketBits; j++ {
			mask := uint64(1 << streamOffset(j))
			if bucket&mask == 0 {
				if atomic.CompareAndSwapUint64(&s.streams[pos], bucket, bucket|mask) {
					atomic.AddInt32(&s.inuseStreams, 1)
					return streamFromBucket(int(pos), j), true
				}
				bucket = atomic.LoadUint64(&s.streams[offset])
			}
		}
	}

	return 0, false
}

func (t *lockstepBusySim) loop(e *entity) {
	lastnotify := t.notify
	t.wg.Done()
	runtime.Gosched()
	for {
		notify := atomic.LoadUint32(&t.notify)
		backoff := 0
		for notify == lastnotify {
			if backoff < 5 {
				runtime.Gosched()
			} else {
				time.Sleep(1000)
			}
			backoff++
			notify = atomic.LoadUint32(&t.notify)
		}
		lastnotify = notify
		fn := t.state
		if fn == nil {
			t.wg.Done()
			break
		}
		fn(e)
		t.wg.Done()
	}
}

// Establishes a new socket connection to the 9P server and creates
// a client object for it. Negotiates the dialect and msize for the
// connection. Returns a Clnt object, or Error.
func Connect(c net.Conn, msize uint32, dotu bool) (*Clnt, error) {
	clnt := NewClnt(c, msize, dotu)
	ver := "9P2000"
	if clnt.Dotu {
		ver = "9P2000.u"
	}

	clntmsize := atomic.LoadUint32(&clnt.Msize)
	tc := ninep.NewFcall(clntmsize)
	err := ninep.PackTversion(tc, clntmsize, ver)
	if err != nil {
		return nil, err
	}

	rc, err := clnt.Rpc(tc)
	if err != nil {
		return nil, err
	}

	if rc.Msize < atomic.LoadUint32(&clnt.Msize) {
		atomic.StoreUint32(&clnt.Msize, rc.Msize)
	}

	clnt.Dotu = rc.Version == "9P2000.u" && clnt.Dotu
	return clnt, nil
}

// Test that Pool does not hold pointers to previously cached
// resources
func TestPoolGC(t *testing.T) {
	var p Pool
	var fin uint32
	const N = 100
	for i := 0; i < N; i++ {
		v := new(string)
		runtime.SetFinalizer(v, func(vv *string) {
			atomic.AddUint32(&fin, 1)
		})
		p.Put(v)
	}
	for i := 0; i < N; i++ {
		p.Get()
	}
	for i := 0; i < 5; i++ {
		runtime.GC()
		time.Sleep(time.Millisecond)
		// 1 pointer can remain on stack or elsewhere
		if atomic.LoadUint32(&fin) >= N-1 {
			return
		}

		// gccgo has a less precise heap.
		if runtime.Compiler == "gccgo" && atomic.LoadUint32(&fin) >= N-5 {
			return
		}
	}
	t.Fatalf("only %v out of %v resources are finalized",
		atomic.LoadUint32(&fin), N)
}

// TestV2NoRetryEOF tests destructive api calls won't retry on a disconnection.
func TestV2NoRetryEOF(t *testing.T) {
	defer testutil.AfterTest(t)
	// generate an EOF response; specify address so appears first in sorted ep list
	lEOF := integration.NewListenerWithAddr(t, fmt.Sprintf("eof:123.%d.sock", os.Getpid()))
	defer lEOF.Close()
	tries := uint32(0)
	go func() {
		for {
			conn, err := lEOF.Accept()
			if err != nil {
				return
			}
			atomic.AddUint32(&tries, 1)
			conn.Close()
		}
	}()
	eofURL := integration.UrlScheme + "://" + lEOF.Addr().String()
	cli := integration.MustNewHTTPClient(t, []string{eofURL, eofURL}, nil)
	kapi := client.NewKeysAPI(cli)
	for i, f := range noRetryList(kapi) {
		startTries := atomic.LoadUint32(&tries)
		if err := f(); err == nil {
			t.Errorf("#%d: expected EOF error, got nil", i)
		}
		endTries := atomic.LoadUint32(&tries)
		if startTries+1 != endTries {
			t.Errorf("#%d: expected 1 try, got %d", i, endTries-startTries)
		}
	}
}

func getAllCallbackGauges() ([]IntMetric, []FloatMetric) {
	numIDs := int(atomic.LoadUint32(curIntCbID))
	retint := make([]IntMetric, numIDs)

	for i := 0; i < numIDs; i++ {
		retint[i] = IntMetric{
			Name: intcbnames[i],
			Val:  intcallbacks[i](),
			Tgs:  intcbtags[i],
		}
	}

	numIDs = int(atomic.LoadUint32(curFloatCbID))
	retfloat := make([]FloatMetric, numIDs)

	for i := 0; i < numIDs; i++ {
		retfloat[i] = FloatMetric{
			Name: floatcbnames[i],
			Val:  floatcallbacks[i](),
			Tgs:  floatcbtags[i],
		}
	}

	return retint, retfloat
}

// Tests that fast sync gets disabled as soon as a real block is successfully
// imported into the blockchain.
func TestFastSyncDisabling(t *testing.T) {
	// Create a pristine protocol manager, check that fast sync is left enabled
	pmEmpty := newTestProtocolManagerMust(t, true, 0, nil, nil)
	if atomic.LoadUint32(&pmEmpty.fastSync) == 0 {
		t.Fatalf("fast sync disabled on pristine blockchain")
	}
	// Create a full protocol manager, check that fast sync gets disabled
	pmFull := newTestProtocolManagerMust(t, true, 1024, nil, nil)
	if atomic.LoadUint32(&pmFull.fastSync) == 1 {
		t.Fatalf("fast sync not disabled on non-empty blockchain")
	}
	// Sync up the two peers
	io1, io2 := p2p.MsgPipe()

	go pmFull.handle(pmFull.newPeer(63, p2p.NewPeer(discover.NodeID{}, "empty", nil), io2))
	go pmEmpty.handle(pmEmpty.newPeer(63, p2p.NewPeer(discover.NodeID{}, "full", nil), io1))

	time.Sleep(250 * time.Millisecond)
	pmEmpty.synchronise(pmEmpty.peers.BestPeer())

	// Check that fast sync was disabled
	if atomic.LoadUint32(&pmEmpty.fastSync) == 1 {
		t.Fatalf("fast sync not disabled after successful synchronisation")
	}
}

// synchronise tries to sync up our local block chain with a remote peer.
func (pm *ProtocolManager) synchronise(peer *peer) {
	// Short circuit if no peers are available
	if peer == nil {
		return
	}
	// Make sure the peer's TD is higher than our own
	currentBlock := pm.blockchain.CurrentBlock()
	td := pm.blockchain.GetTd(currentBlock.Hash())

	pHead, pTd := peer.Head()
	if pTd.Cmp(td) <= 0 {
		return
	}
	// Otherwise try to sync with the downloader
	mode := downloader.FullSync
	if atomic.LoadUint32(&pm.fastSync) == 1 {
		mode = downloader.FastSync
	}
	if err := pm.downloader.Synchronise(peer.id, pHead, pTd, mode); err != nil {
		return
	}
	atomic.StoreUint32(&pm.synced, 1) // Mark initial sync done

	// If fast sync was enabled, and we synced up, disable it
	if atomic.LoadUint32(&pm.fastSync) == 1 {
		// Disable fast sync if we indeed have something in our chain
		if pm.blockchain.CurrentBlock().NumberU64() > 0 {
			glog.V(logger.Info).Infof("fast sync complete, auto disabling")
			atomic.StoreUint32(&pm.fastSync, 0)
		}
	}
}

// Test that Pool does not hold pointers to previously cached
// resources
func TestPoolGC(t *testing.T) {
	var p Pool
	var fin uint32
	const N = 100
	for i := 0; i < N; i++ {
		v := new(string)
		runtime.SetFinalizer(v, func(vv *string) {
			atomic.AddUint32(&fin, 1)
		})
		p.Put(uint32(i), v)
	}
	for i := 0; i < N; i++ {
		p.Get(uint32(i))
	}
	for i := 0; i < 5; i++ {
		runtime.GC()
		time.Sleep(time.Duration(i*100+10) * time.Millisecond)
		// 1 pointer can remain on stack or elsewhere
		if atomic.LoadUint32(&fin) >= N-1 {
			return
		}
	}
	t.Fatalf("only %v out of %v resources are finalized",
		atomic.LoadUint32(&fin), N)
}