Adjusts timers and passes the main thread directly to scaling.

frankenphp.go

@@ -333,7 +333,8 @@ func Init(options ...Option) error {
 		logger.Warn(`ZTS is not enabled, only 1 thread will be available, recompile PHP using the "--enable-zts" configuration option or performance will be degraded`)
 	}
 
-	if err := initPHPThreads(totalThreadCount, maxThreadCount, opt.phpIniOverrides); err != nil {
+	mainThread, err := initPHPThreads(totalThreadCount, maxThreadCount, opt.phpIniOverrides)
+	if err != nil {
 		return err
 	}
 
@@ -348,7 +349,7 @@ func Init(options ...Option) error {
 		return err
 	}
 
-	initAutoScaling(mainThread.numThreads, mainThread.maxThreads)
+	initAutoScaling(mainThread)
 
 	if c := logger.Check(zapcore.InfoLevel, "FrankenPHP started 🐘"); c != nil {
 		c.Write(zap.String("php_version", Version().Version), zap.Int("num_threads", mainThread.numThreads), zap.Int("max_threads", mainThread.maxThreads))

internal/cpu/cpu_fallback.go

@@ -10,11 +10,10 @@ import (
 
 // The fallback always determines that the CPU limits are not reached
 func ProbeCPUs(probeTime time.Duration, maxCPUUsage float64, abort chan struct{}) bool {
-	timer := time.NewTimer(probeTime)
 	select {
 	case <-abort:
 		return false
-	case <-timer.C:
+	case <-time.After(probeTime):
 		return true
 	}
 }

internal/cpu/cpu_unix.go

@@ -23,11 +23,10 @@ func ProbeCPUs(probeTime time.Duration, maxCPUUsage float64, abort chan struct{}
 	C.clock_gettime(C.CLOCK_MONOTONIC, &start)
 	C.clock_gettime(C.CLOCK_PROCESS_CPUTIME_ID, &cpuStart)
 
-	timer := time.NewTimer(probeTime)
 	select {
 	case <-abort:
 		return false
-	case <-timer.C:
+	case <-time.After(probeTime):
 	}
 
 	C.clock_gettime(C.CLOCK_MONOTONIC, &end)

internal/memory/memory_fallback.go

@@ -4,8 +4,6 @@
 
 package memory
 
-import "syscall"
-
 // Return 0 if the total system memory cannot be determined
 func TotalSysMemory() uint64 {
 	return 0

phpmainthread.go

@@ -28,7 +28,7 @@ var (
 // start the main PHP thread
 // start a fixed number of inactive PHP threads
 // reserve a fixed number of possible PHP threads
-func initPHPThreads(numThreads int, numMaxThreads int, phpIniOverrides map[string]string) error {
+func initPHPThreads(numThreads int, numMaxThreads int, phpIniOverrides map[string]string) (*phpMainThread, error) {
 	mainThread = &phpMainThread{
 		state:           newThreadState(),
 		done:            make(chan struct{}),
@@ -45,7 +45,7 @@ func initPHPThreads(numThreads int, numMaxThreads int, phpIniOverrides map[strin
 	phpThreads = []*phpThread{initialThread}
 
 	if err := mainThread.start(); err != nil {
-		return err
+		return nil, err
 	}
 
 	// initialize all other threads
@@ -67,7 +67,7 @@ func initPHPThreads(numThreads int, numMaxThreads int, phpIniOverrides map[strin
 	}
 	ready.Wait()
 
-	return nil
+	return mainThread, nil
 }
 
 // ThreadDebugStatus prints the state of all PHP threads - debugging purposes only

phpmainthread_test.go

@@ -17,8 +17,9 @@ import (
 var testDataPath, _ = filepath.Abs("./testdata")
 
 func TestStartAndStopTheMainThreadWithOneInactiveThread(t *testing.T) {
-	logger = zap.NewNop()                        // the logger needs to not be nil
-	assert.NoError(t, initPHPThreads(1, 1, nil)) // boot 1 thread
+	logger = zap.NewNop()               // the logger needs to not be nil
+	_, err := initPHPThreads(1, 1, nil) // boot 1 thread
+	assert.NoError(t, err)
 
 	assert.Len(t, phpThreads, 1)
 	assert.Equal(t, 0, phpThreads[0].threadIndex)
@@ -30,7 +31,8 @@ func TestStartAndStopTheMainThreadWithOneInactiveThread(t *testing.T) {
 
 func TestTransitionRegularThreadToWorkerThread(t *testing.T) {
 	logger = zap.NewNop()
-	assert.NoError(t, initPHPThreads(1, 1, nil))
+	_, err := initPHPThreads(1, 1, nil)
+	assert.NoError(t, err)
 
 	// transition to regular thread
 	convertToRegularThread(phpThreads[0])
@@ -53,7 +55,8 @@ func TestTransitionRegularThreadToWorkerThread(t *testing.T) {
 
 func TestTransitionAThreadBetween2DifferentWorkers(t *testing.T) {
 	logger = zap.NewNop()
-	assert.NoError(t, initPHPThreads(1, 1, nil))
+	_, err := initPHPThreads(1, 1, nil)
+	assert.NoError(t, err)
 	firstWorker := getDummyWorker("transition-worker-1.php")
 	secondWorker := getDummyWorker("transition-worker-2.php")
 

scaling.go

@@ -42,13 +42,16 @@ var (
 	WorkerNotFoundError         = errors.New("worker not found for given filename")
 )
 
-func initAutoScaling(numThreads int, maxThreads int) {
-	if maxThreads <= numThreads {
+func initAutoScaling(mainThread *phpMainThread) {
+	if mainThread.maxThreads <= mainThread.numThreads {
 		return
 	}
 
-	maxScaledThreads := maxThreads - numThreads
+	maxScaledThreads := mainThread.maxThreads - mainThread.numThreads
+	scalingMu.Lock()
 	autoScaledThreads = make([]*phpThread, 0, maxScaledThreads)
+	scalingMu.Unlock()
+
 	go startUpscalingThreads(mainThread.done, maxScaledThreads)
 	go startDownScalingThreads(mainThread.done)
 }
@@ -197,8 +200,13 @@ func startUpscalingThreads(done chan struct{}, maxScaledThreads int) {
 		scaledThreadCount := len(autoScaledThreads)
 		scalingMu.Unlock()
 		if scaledThreadCount >= maxScaledThreads {
-			time.Sleep(upscaleCheckTime)
-			continue
+			// we have reached max_threads, check again later
+			select {
+			case <-done:
+				return
+			case <-time.After(downScaleCheckTime):
+				continue
+			}
 		}
 
 		select {
@@ -207,8 +215,12 @@ func startUpscalingThreads(done chan struct{}, maxScaledThreads int) {
 
 			// if the request has not been stalled long enough, wait and repeat
 			if timeSinceStalled < minStallTime {
-				time.Sleep(upscaleCheckTime)
-				continue
+				select {
+				case <-done:
+					return
+				case <-time.After(minStallTime - timeSinceStalled):
+					continue
+				}
 			}
 
 			// if the request has been stalled long enough, scale
@@ -224,14 +236,12 @@ func startUpscalingThreads(done chan struct{}, maxScaledThreads int) {
 }
 
 func startDownScalingThreads(done chan struct{}) {
-	timer := time.NewTimer(downScaleCheckTime)
 	for {
 		select {
 		case <-done:
 			return
-		case <-timer.C:
+		case <-time.After(downScaleCheckTime):
 			deactivateThreads()
-			timer.Reset(downScaleCheckTime)
 		}
 	}
 }