perf: remove all cgo handles (#1073)

* Removes Cgo handles and adds phpThreads.

* Changes variable name.

* Changes variable name.

* Fixes merge error.

* Removes unnecessary 'workers are done' check.

* Removes panic.

* Replaces int with uint32_t.

* Changes index type to uintptr_t.

* simplify

---------

Co-authored-by: a.stecher <a.stecher@sportradar.com>
Co-authored-by: Kévin Dunglas <kevin@dunglas.fr>

frankenphp.c

@@ -70,14 +70,15 @@ frankenphp_config frankenphp_get_config() {
 }
 
 typedef struct frankenphp_server_context {
-  uintptr_t current_request;
-  uintptr_t main_request;
+  bool has_main_request;
+  bool has_active_request;
   bool worker_ready;
   char *cookie_data;
   bool finished;
 } frankenphp_server_context;
 
 __thread frankenphp_server_context *local_ctx = NULL;
+__thread uintptr_t thread_index;
 
 static void frankenphp_free_request_context() {
   frankenphp_server_context *ctx = SG(server_context);
@@ -231,9 +232,8 @@ PHP_FUNCTION(frankenphp_finish_request) { /* {{{ */
   php_output_end_all();
   php_header();
 
-  if (ctx->current_request != 0) {
-    go_frankenphp_finish_request(ctx->main_request, ctx->current_request,
-                                 false);
+  if (ctx->has_active_request) {
+    go_frankenphp_finish_request(thread_index, false);
   }
 
   ctx->finished = true;
@@ -249,7 +249,7 @@ PHP_FUNCTION(frankenphp_request_headers) {
 
   frankenphp_server_context *ctx = SG(server_context);
   struct go_apache_request_headers_return headers =
-      go_apache_request_headers(ctx->current_request, ctx->main_request);
+      go_apache_request_headers(thread_index, ctx->has_active_request);
 
   array_init_size(return_value, headers.r1);
 
@@ -260,7 +260,7 @@ PHP_FUNCTION(frankenphp_request_headers) {
     add_assoc_stringl_ex(return_value, key.data, key.len, val.data, val.len);
   }
 
-  go_apache_request_cleanup(headers.r2);
+  go_apache_request_cleanup(thread_index);
 }
 /* }}} */
 
@@ -327,7 +327,7 @@ PHP_FUNCTION(frankenphp_handle_request) {
 
   frankenphp_server_context *ctx = SG(server_context);
 
-  if (ctx->main_request == 0) {
+  if (!ctx->has_main_request) {
     /* not a worker, throw an error */
     zend_throw_exception(
         spl_ce_RuntimeException,
@@ -340,9 +340,6 @@ PHP_FUNCTION(frankenphp_handle_request) {
     frankenphp_worker_request_shutdown();
 
     ctx->worker_ready = true;
-
-    /* Mark the worker as ready to handle requests */
-    go_frankenphp_worker_ready(ctx->main_request);
   }
 
 #ifdef ZEND_MAX_EXECUTION_TIMERS
@@ -350,8 +347,7 @@ PHP_FUNCTION(frankenphp_handle_request) {
   zend_unset_timeout();
 #endif
 
-  uintptr_t request =
-      go_frankenphp_worker_handle_request_start(ctx->main_request);
+  bool request = go_frankenphp_worker_handle_request_start(thread_index);
   if (frankenphp_worker_request_startup() == FAILURE
       /* Shutting down */
       || !request) {
@@ -384,8 +380,8 @@ PHP_FUNCTION(frankenphp_handle_request) {
   }
 
   frankenphp_worker_request_shutdown();
-  ctx->current_request = 0;
-  go_frankenphp_finish_request(ctx->main_request, request, true);
+  ctx->has_active_request = false;
+  go_frankenphp_finish_request(thread_index, true);
 
   RETURN_TRUE;
 }
@@ -426,7 +422,7 @@ static zend_module_entry frankenphp_module = {
 static void frankenphp_request_shutdown() {
   frankenphp_server_context *ctx = SG(server_context);
 
-  if (ctx->main_request && ctx->current_request) {
+  if (ctx->has_main_request && ctx->has_active_request) {
     frankenphp_destroy_super_globals();
   }
 
@@ -437,7 +433,7 @@ static void frankenphp_request_shutdown() {
 }
 
 int frankenphp_update_server_context(
-    bool create, uintptr_t current_request, uintptr_t main_request,
+    bool create, bool has_main_request, bool has_active_request,
 
     const char *request_method, char *query_string, zend_long content_length,
     char *path_translated, char *request_uri, const char *content_type,
@@ -459,8 +455,8 @@ int frankenphp_update_server_context(
   // It is not reset by zend engine, set it to 200.
   SG(sapi_headers).http_response_code = 200;
 
-  ctx->main_request = main_request;
-  ctx->current_request = current_request;
+  ctx->has_main_request = has_main_request;
+  ctx->has_active_request = has_active_request;
 
   SG(request_info).auth_password = auth_password;
   SG(request_info).auth_user = auth_user;
@@ -493,9 +489,8 @@ static size_t frankenphp_ub_write(const char *str, size_t str_length) {
     return 0;
   }
 
-  struct go_ub_write_return result = go_ub_write(
-      ctx->current_request ? ctx->current_request : ctx->main_request,
-      (char *)str, str_length);
+  struct go_ub_write_return result =
+      go_ub_write(thread_index, (char *)str, str_length);
 
   if (result.r1) {
     php_handle_aborted_connection();
@@ -512,7 +507,7 @@ static int frankenphp_send_headers(sapi_headers_struct *sapi_headers) {
   int status;
   frankenphp_server_context *ctx = SG(server_context);
 
-  if (ctx->current_request == 0) {
+  if (!ctx->has_active_request) {
     return SAPI_HEADER_SEND_FAILED;
   }
 
@@ -526,7 +521,7 @@ static int frankenphp_send_headers(sapi_headers_struct *sapi_headers) {
     }
   }
 
-  go_write_headers(ctx->current_request, status, &sapi_headers->headers);
+  go_write_headers(thread_index, status, &sapi_headers->headers);
 
   return SAPI_HEADER_SENT_SUCCESSFULLY;
 }
@@ -534,7 +529,7 @@ static int frankenphp_send_headers(sapi_headers_struct *sapi_headers) {
 static void frankenphp_sapi_flush(void *server_context) {
   frankenphp_server_context *ctx = (frankenphp_server_context *)server_context;
 
-  if (ctx && ctx->current_request != 0 && go_sapi_flush(ctx->current_request)) {
+  if (ctx && ctx->has_active_request && go_sapi_flush(thread_index)) {
     php_handle_aborted_connection();
   }
 }
@@ -542,19 +537,19 @@ static void frankenphp_sapi_flush(void *server_context) {
 static size_t frankenphp_read_post(char *buffer, size_t count_bytes) {
   frankenphp_server_context *ctx = SG(server_context);
 
-  return ctx->current_request
-             ? go_read_post(ctx->current_request, buffer, count_bytes)
+  return ctx->has_active_request
+             ? go_read_post(thread_index, buffer, count_bytes)
              : 0;
 }
 
 static char *frankenphp_read_cookies(void) {
   frankenphp_server_context *ctx = SG(server_context);
 
-  if (ctx->current_request == 0) {
+  if (!ctx->has_active_request) {
     return "";
   }
 
-  ctx->cookie_data = go_read_cookies(ctx->current_request);
+  ctx->cookie_data = go_read_cookies(thread_index);
 
   return ctx->cookie_data;
 }
@@ -664,16 +659,13 @@ void frankenphp_register_bulk_variables(go_string known_variables[27],
 
 static void frankenphp_register_variables(zval *track_vars_array) {
   /* https://www.php.net/manual/en/reserved.variables.server.php */
-  frankenphp_server_context *ctx = SG(server_context);
 
   /* In CGI mode, we consider the environment to be a part of the server
    * variables
    */
   php_import_environment_variables(track_vars_array);
 
-  go_register_variables(ctx->current_request ? ctx->current_request
-                                             : ctx->main_request,
-                        track_vars_array);
+  go_register_variables(thread_index, track_vars_array);
 }
 
 static void frankenphp_log_message(const char *message, int syslog_type_int) {
@@ -732,6 +724,7 @@ static void set_thread_name(char *thread_name) {
 static void *php_thread(void *arg) {
   char thread_name[16] = {0};
   snprintf(thread_name, 16, "php-%" PRIxPTR, (uintptr_t)arg);
+  thread_index = (uintptr_t)arg;
   set_thread_name(thread_name);
 
 #ifdef ZTS
@@ -744,7 +737,7 @@ static void *php_thread(void *arg) {
 
   local_ctx = malloc(sizeof(frankenphp_server_context));
 
-  while (go_handle_request()) {
+  while (go_handle_request(thread_index)) {
   }
 
 #ifdef ZTS

frankenphp.go

@@ -35,7 +35,6 @@ import (
 	"net/http"
 	"os"
 	"runtime"
-	"runtime/cgo"
 	"strconv"
 	"strings"
 	"sync"
@@ -50,10 +49,8 @@ import (
 )
 
 type contextKeyStruct struct{}
-type handleKeyStruct struct{}
 
 var contextKey = contextKeyStruct{}
-var handleKey = handleKeyStruct{}
 
 var (
 	InvalidRequestError         = errors.New("not a FrankenPHP request")
@@ -125,15 +122,11 @@ type FrankenPHPContext struct {
 	// Whether the request is already closed by us
 	closed sync.Once
 
-	// whether the context is ready to receive requests
-	ready bool
-
 	responseWriter http.ResponseWriter
 	exitStatus     C.int
 
-	done                 chan interface{}
-	currentWorkerRequest cgo.Handle
-	startedAt            time.Time
+	done      chan interface{}
+	startedAt time.Time
 }
 
 func clientHasClosed(r *http.Request) bool {
@@ -197,7 +190,6 @@ func NewRequestWithContext(r *http.Request, opts ...RequestOption) (*http.Reques
 	fc.scriptFilename = sanitizedPathJoin(fc.documentRoot, fc.scriptName)
 
 	c := context.WithValue(r.Context(), contextKey, fc)
-	c = context.WithValue(c, handleKey, Handles())
 
 	return r.WithContext(c), nil
 }
@@ -338,6 +330,7 @@ func Init(options ...Option) error {
 	shutdownWG.Add(1)
 	done = make(chan struct{})
 	requestChan = make(chan *http.Request)
+	initPHPThreads(opt.numThreads)
 
 	if C.frankenphp_init(C.int(opt.numThreads)) != 0 {
 		return MainThreadCreationError
@@ -386,6 +379,7 @@ func go_shutdown() {
 func drainThreads() {
 	close(done)
 	shutdownWG.Wait()
+	phpThreads = nil
 }
 
 func getLogger() *zap.Logger {
@@ -395,7 +389,7 @@ func getLogger() *zap.Logger {
 	return logger
 }
 
-func updateServerContext(request *http.Request, create bool, mrh C.uintptr_t) error {
+func updateServerContext(request *http.Request, create bool, isWorkerRequest bool) error {
 	fc, ok := FromContext(request.Context())
 	if !ok {
 		return InvalidRequestError
@@ -437,21 +431,12 @@ func updateServerContext(request *http.Request, create bool, mrh C.uintptr_t) er
 	}
 
 	cRequestUri := C.CString(request.URL.RequestURI())
-
-	var rh cgo.Handle
-	if fc.responseWriter == nil {
-		h := cgo.NewHandle(request)
-		request.Context().Value(handleKey).(*handleList).AddHandle(h)
-		mrh = C.uintptr_t(h)
-	} else {
-		rh = cgo.NewHandle(request)
-		request.Context().Value(handleKey).(*handleList).AddHandle(rh)
-	}
+	isBootingAWorkerScript := fc.responseWriter == nil
 
 	ret := C.frankenphp_update_server_context(
 		C.bool(create),
-		C.uintptr_t(rh),
-		mrh,
+		C.bool(isWorkerRequest || isBootingAWorkerScript),
+		C.bool(!isBootingAWorkerScript),
 
 		cMethod,
 		cQueryString,
@@ -490,10 +475,10 @@ func ServeHTTP(responseWriter http.ResponseWriter, request *http.Request) error
 	rc := requestChan
 	// Detect if a worker is available to handle this request
 	if !isWorker {
-		if v, ok := workersRequestChans.Load(fc.scriptFilename); ok {
+		if worker, ok := workers[fc.scriptFilename]; ok {
 			isWorkerRequest = true
 			metrics.StartWorkerRequest(fc.scriptFilename)
-			rc = v.(chan *http.Request)
+			rc = worker.requestChan
 		} else {
 			metrics.StartRequest()
 		}
@@ -517,14 +502,14 @@ func ServeHTTP(responseWriter http.ResponseWriter, request *http.Request) error
 }
 
 //export go_handle_request
-func go_handle_request() bool {
+func go_handle_request(threadIndex C.uintptr_t) bool {
 	select {
 	case <-done:
 		return false
 
 	case r := <-requestChan:
-		h := cgo.NewHandle(r)
-		r.Context().Value(handleKey).(*handleList).AddHandle(h)
+		thread := phpThreads[threadIndex]
+		thread.mainRequest = r
 
 		fc, ok := FromContext(r.Context())
 		if !ok {
@@ -532,10 +517,10 @@ func go_handle_request() bool {
 		}
 		defer func() {
 			maybeCloseContext(fc)
-			r.Context().Value(handleKey).(*handleList).FreeAll()
+			thread.mainRequest = nil
 		}()
 
-		if err := updateServerContext(r, true, 0); err != nil {
+		if err := updateServerContext(r, true, false); err != nil {
 			panic(err)
 		}
 
@@ -556,8 +541,8 @@ func maybeCloseContext(fc *FrankenPHPContext) {
 }
 
 //export go_ub_write
-func go_ub_write(rh C.uintptr_t, cBuf *C.char, length C.int) (C.size_t, C.bool) {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_ub_write(threadIndex C.uintptr_t, cBuf *C.char, length C.int) (C.size_t, C.bool) {
+	r := phpThreads[threadIndex].getActiveRequest()
 	fc, _ := FromContext(r.Context())
 
 	var writer io.Writer
@@ -595,12 +580,11 @@ var headerKeyCache = func() otter.Cache[string, string] {
 }()
 
 //export go_register_variables
-func go_register_variables(rh C.uintptr_t, trackVarsArray *C.zval) {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_register_variables(threadIndex C.uintptr_t, trackVarsArray *C.zval) {
+	thread := phpThreads[threadIndex]
+	r := thread.getActiveRequest()
 	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
 
-	p := &runtime.Pinner{}
-
 	dynamicVariables := make([]C.php_variable, len(fc.env)+len(r.Header))
 
 	var l int
@@ -622,8 +606,8 @@ func go_register_variables(rh C.uintptr_t, trackVarsArray *C.zval) {
 		kData := unsafe.StringData(k)
 		vData := unsafe.StringData(v)
 
-		p.Pin(kData)
-		p.Pin(vData)
+		thread.Pin(kData)
+		thread.Pin(vData)
 
 		dynamicVariables[l]._var = (*C.char)(unsafe.Pointer(kData))
 		dynamicVariables[l].data_len = C.size_t(len(v))
@@ -640,8 +624,8 @@ func go_register_variables(rh C.uintptr_t, trackVarsArray *C.zval) {
 		kData := unsafe.StringData(k)
 		vData := unsafe.Pointer(unsafe.StringData(v))
 
-		p.Pin(kData)
-		p.Pin(vData)
+		thread.Pin(kData)
+		thread.Pin(vData)
 
 		dynamicVariables[l]._var = (*C.char)(unsafe.Pointer(kData))
 		dynamicVariables[l].data_len = C.size_t(len(v))
@@ -650,45 +634,43 @@ func go_register_variables(rh C.uintptr_t, trackVarsArray *C.zval) {
 		l++
 	}
 
-	knownVariables := computeKnownVariables(r, p)
+	knownVariables := computeKnownVariables(r, &thread.Pinner)
 
 	dvsd := unsafe.SliceData(dynamicVariables)
-	p.Pin(dvsd)
+	thread.Pin(dvsd)
 
 	C.frankenphp_register_bulk_variables(&knownVariables[0], dvsd, C.size_t(l), trackVarsArray)
 
-	p.Unpin()
+	thread.Unpin()
 
 	fc.env = nil
 }
 
 //export go_apache_request_headers
-func go_apache_request_headers(rh, mrh C.uintptr_t) (*C.go_string, C.size_t, C.uintptr_t) {
-	if rh == 0 {
+func go_apache_request_headers(threadIndex C.uintptr_t, hasActiveRequest bool) (*C.go_string, C.size_t) {
+	thread := phpThreads[threadIndex]
+
+	if !hasActiveRequest {
 		// worker mode, not handling a request
-		mr := cgo.Handle(mrh).Value().(*http.Request)
-		mfc := mr.Context().Value(contextKey).(*FrankenPHPContext)
+		mfc := thread.mainRequest.Context().Value(contextKey).(*FrankenPHPContext)
 
 		if c := mfc.logger.Check(zapcore.DebugLevel, "apache_request_headers() called in non-HTTP context"); c != nil {
 			c.Write(zap.String("worker", mfc.scriptFilename))
 		}
 
-		return nil, 0, 0
+		return nil, 0
 	}
-	r := cgo.Handle(rh).Value().(*http.Request)
-
-	pinner := &runtime.Pinner{}
-	pinnerHandle := C.uintptr_t(cgo.NewHandle(pinner))
+	r := thread.getActiveRequest()
 
 	headers := make([]C.go_string, 0, len(r.Header)*2)
 
 	for field, val := range r.Header {
 		fd := unsafe.StringData(field)
-		pinner.Pin(fd)
+		thread.Pin(fd)
 
 		cv := strings.Join(val, ", ")
 		vd := unsafe.StringData(cv)
-		pinner.Pin(vd)
+		thread.Pin(vd)
 
 		headers = append(
 			headers,
@@ -698,21 +680,14 @@ func go_apache_request_headers(rh, mrh C.uintptr_t) (*C.go_string, C.size_t, C.u
 	}
 
 	sd := unsafe.SliceData(headers)
-	pinner.Pin(sd)
+	thread.Pin(sd)
 
-	return sd, C.size_t(len(r.Header)), pinnerHandle
+	return sd, C.size_t(len(r.Header))
 }
 
 //export go_apache_request_cleanup
-func go_apache_request_cleanup(rh C.uintptr_t) {
-	if rh == 0 {
-		return
-	}
-
-	h := cgo.Handle(rh)
-	p := h.Value().(*runtime.Pinner)
-	p.Unpin()
-	h.Delete()
+func go_apache_request_cleanup(threadIndex C.uintptr_t) {
+	phpThreads[threadIndex].Unpin()
 }
 
 func addHeader(fc *FrankenPHPContext, cString *C.char, length C.int) {
@@ -729,8 +704,8 @@ func addHeader(fc *FrankenPHPContext, cString *C.char, length C.int) {
 }
 
 //export go_write_headers
-func go_write_headers(rh C.uintptr_t, status C.int, headers *C.zend_llist) {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_write_headers(threadIndex C.uintptr_t, status C.int, headers *C.zend_llist) {
+	r := phpThreads[threadIndex].getActiveRequest()
 	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
 
 	if fc.responseWriter == nil {
@@ -757,8 +732,8 @@ func go_write_headers(rh C.uintptr_t, status C.int, headers *C.zend_llist) {
 }
 
 //export go_sapi_flush
-func go_sapi_flush(rh C.uintptr_t) bool {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_sapi_flush(threadIndex C.uintptr_t) bool {
+	r := phpThreads[threadIndex].getActiveRequest()
 	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
 
 	if fc.responseWriter == nil || clientHasClosed(r) {
@@ -775,8 +750,8 @@ func go_sapi_flush(rh C.uintptr_t) bool {
 }
 
 //export go_read_post
-func go_read_post(rh C.uintptr_t, cBuf *C.char, countBytes C.size_t) (readBytes C.size_t) {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_read_post(threadIndex C.uintptr_t, cBuf *C.char, countBytes C.size_t) (readBytes C.size_t) {
+	r := phpThreads[threadIndex].getActiveRequest()
 
 	p := unsafe.Slice((*byte)(unsafe.Pointer(cBuf)), countBytes)
 	var err error
@@ -790,8 +765,8 @@ func go_read_post(rh C.uintptr_t, cBuf *C.char, countBytes C.size_t) (readBytes
 }
 
 //export go_read_cookies
-func go_read_cookies(rh C.uintptr_t) *C.char {
-	r := cgo.Handle(rh).Value().(*http.Request)
+func go_read_cookies(threadIndex C.uintptr_t) *C.char {
+	r := phpThreads[threadIndex].getActiveRequest()
 
 	cookies := r.Cookies()
 	if len(cookies) == 0 {

frankenphp.h

@@ -43,7 +43,7 @@ frankenphp_config frankenphp_get_config();
 int frankenphp_init(int num_threads);
 
 int frankenphp_update_server_context(
-    bool create, uintptr_t current_request, uintptr_t main_request,
+    bool create, bool has_main_request, bool has_active_request,
 
     const char *request_method, char *query_string, zend_long content_length,
     char *path_translated, char *request_uri, const char *content_type,

php_thread.go

@@ -0,0 +1,33 @@
+package frankenphp
+
+// #include <stdint.h>
+import "C"
+import (
+	"net/http"
+	"runtime"
+)
+
+var phpThreads []*phpThread
+
+type phpThread struct {
+	runtime.Pinner
+
+	mainRequest   *http.Request
+	workerRequest *http.Request
+	worker        *worker
+}
+
+func initPHPThreads(numThreads int) {
+	phpThreads = make([]*phpThread, 0, numThreads)
+	for i := 0; i < numThreads; i++ {
+		phpThreads = append(phpThreads, &phpThread{})
+	}
+}
+
+func (thread phpThread) getActiveRequest() *http.Request {
+	if thread.workerRequest != nil {
+		return thread.workerRequest
+	}
+
+	return thread.mainRequest
+}

php_thread_test.go

@@ -0,0 +1,40 @@
+package frankenphp
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestInitializeTwoPhpThreadsWithoutRequests(t *testing.T) {
+	initPHPThreads(2)
+
+	assert.Len(t, phpThreads, 2)
+	assert.NotNil(t, phpThreads[0])
+	assert.NotNil(t, phpThreads[1])
+	assert.Nil(t, phpThreads[0].mainRequest)
+	assert.Nil(t, phpThreads[0].workerRequest)
+}
+
+func TestMainRequestIsActiveRequest(t *testing.T) {
+	mainRequest := &http.Request{}
+	initPHPThreads(1)
+	thread := phpThreads[0]
+
+	thread.mainRequest = mainRequest
+
+	assert.Equal(t, mainRequest, thread.getActiveRequest())
+}
+
+func TestWorkerRequestIsActiveRequest(t *testing.T) {
+	mainRequest := &http.Request{}
+	workerRequest := &http.Request{}
+	initPHPThreads(1)
+	thread := phpThreads[0]
+
+	thread.mainRequest = mainRequest
+	thread.workerRequest = workerRequest
+
+	assert.Equal(t, workerRequest, thread.getActiveRequest())
+}

smartpointer.go

@@ -1,64 +0,0 @@
-package frankenphp
-
-// #include <stdlib.h>
-import "C"
-import (
-	"runtime/cgo"
-	"unsafe"
-)
-
-/*
-FrankenPHP is fairly complex because it shuffles handles/requests/contexts
-between C and Go. This simplifies the lifecycle management of per-request
-structures by allowing us to hold references until the end of the request
-and ensure they are always cleaned up.
-*/
-
-// PointerList A list of pointers that can be freed at a later time
-type pointerList struct {
-	Pointers []unsafe.Pointer
-}
-
-// HandleList A list of pointers that can be freed at a later time
-type handleList struct {
-	Handles []cgo.Handle
-}
-
-// AddHandle Call when registering a handle for the very first time
-func (h *handleList) AddHandle(handle cgo.Handle) {
-	h.Handles = append(h.Handles, handle)
-}
-
-// AddPointer Call when creating a request-level C pointer for the very first time
-func (p *pointerList) AddPointer(ptr unsafe.Pointer) {
-	p.Pointers = append(p.Pointers, ptr)
-}
-
-// FreeAll frees all C pointers
-func (p *pointerList) FreeAll() {
-	for _, ptr := range p.Pointers {
-		C.free(ptr)
-	}
-	p.Pointers = nil // To avoid dangling pointers
-}
-
-// FreeAll frees all handles
-func (h *handleList) FreeAll() {
-	for _, p := range h.Handles {
-		p.Delete()
-	}
-}
-
-// Pointers Get a new list of pointers
-func Pointers() *pointerList {
-	return &pointerList{
-		Pointers: make([]unsafe.Pointer, 0),
-	}
-}
-
-// Handles Get a new list of handles
-func Handles() *handleList {
-	return &handleList{
-		Handles: make([]cgo.Handle, 0, 8),
-	}
-}

worker.go

@@ -4,11 +4,9 @@ package frankenphp
 // #include "frankenphp.h"
 import "C"
 import (
-	"errors"
 	"fmt"
 	"net/http"
 	"path/filepath"
-	"runtime/cgo"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -18,194 +16,174 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
+type worker struct {
+	fileName    string
+	num         int
+	env         PreparedEnv
+	requestChan chan *http.Request
+}
+
+const maxWorkerErrorBackoff = 1 * time.Second
+const minWorkerErrorBackoff = 100 * time.Millisecond
+const maxWorkerConsecutiveFailures = 60
+
 var (
-	workersRequestChans sync.Map // map[fileName]chan *http.Request
-	workersReadyWG      sync.WaitGroup
-	workerShutdownWG    sync.WaitGroup
-	workersAreReady     atomic.Bool
-	workersAreDone      atomic.Bool
-	workersDone         chan interface{}
+	workersReadyWG   sync.WaitGroup
+	workerShutdownWG sync.WaitGroup
+	workersAreReady  atomic.Bool
+	workersAreDone   atomic.Bool
+	workersDone      chan interface{}
+	workers          map[string]*worker = make(map[string]*worker)
 )
 
-// TODO: start all the worker in parallel to reduce the boot time
 func initWorkers(opt []workerOpt) error {
 	workersDone = make(chan interface{})
 	workersAreReady.Store(false)
 	workersAreDone.Store(false)
 
-	for _, w := range opt {
-		if err := startWorkers(w.fileName, w.num, w.env); err != nil {
+	for _, o := range opt {
+		worker, err := newWorker(o)
+		if err != nil {
 			return err
 		}
-	}
-
-	return nil
-}
-
-func startWorkers(fileName string, nbWorkers int, env PreparedEnv) error {
-	absFileName, err := filepath.Abs(fileName)
-	if err != nil {
-		return fmt.Errorf("workers %q: %w", fileName, err)
-	}
-
-	if _, ok := workersRequestChans.Load(absFileName); !ok {
-		workersRequestChans.Store(absFileName, make(chan *http.Request))
-	}
-
-	shutdownWG.Add(nbWorkers)
-	workerShutdownWG.Add(nbWorkers)
-	workersReadyWG.Add(nbWorkers)
-
-	var (
-		m    sync.RWMutex
-		errs []error
-	)
-
-	if env == nil {
-		env = make(PreparedEnv, 1)
-	}
-
-	env["FRANKENPHP_WORKER\x00"] = "1"
-
-	l := getLogger()
-
-	const maxBackoff = 1 * time.Second
-	const minBackoff = 10 * time.Millisecond
-	const maxConsecutiveFailures = 60
-
-	for i := 0; i < nbWorkers; i++ {
-		go func() {
-			defer shutdownWG.Done()
-			defer workerShutdownWG.Done()
-			backoff := minBackoff
-			failureCount := 0
-			backingOffLock := sync.RWMutex{}
-			for {
-				// if the worker can stay up longer than backoff*2, it is probably an application error
-				upFunc := sync.Once{}
-				go func() {
-					backingOffLock.RLock()
-					wait := backoff * 2
-					backingOffLock.RUnlock()
-					time.Sleep(wait)
-					upFunc.Do(func() {
-						backingOffLock.Lock()
-						defer backingOffLock.Unlock()
-						// if we come back to a stable state, reset the failure count
-						if backoff == minBackoff {
-							failureCount = 0
-						}
-
-						// earn back the backoff over time
-						if failureCount > 0 {
-							backoff = max(backoff/2, 100*time.Millisecond)
-						}
-					})
-				}()
-
-				// Create main dummy request
-				r, err := http.NewRequest(http.MethodGet, filepath.Base(absFileName), nil)
-
-				metrics.StartWorker(absFileName)
-
-				if err != nil {
-					panic(err)
-				}
-				r, err = NewRequestWithContext(
-					r,
-					WithRequestDocumentRoot(filepath.Dir(absFileName), false),
-					WithRequestPreparedEnv(env),
-				)
-				if err != nil {
-					panic(err)
-				}
-
-				if c := l.Check(zapcore.DebugLevel, "starting"); c != nil {
-					c.Write(zap.String("worker", absFileName), zap.Int("num", nbWorkers))
-				}
-
-				if err := ServeHTTP(nil, r); err != nil {
-					panic(err)
-				}
-
-				fc := r.Context().Value(contextKey).(*FrankenPHPContext)
-				if fc.currentWorkerRequest != 0 {
-					// Terminate the pending HTTP request handled by the worker
-					maybeCloseContext(fc.currentWorkerRequest.Value().(*http.Request).Context().Value(contextKey).(*FrankenPHPContext))
-					fc.currentWorkerRequest.Delete()
-					fc.currentWorkerRequest = 0
-				}
-
-				// TODO: make the max restart configurable
-				if !workersAreDone.Load() {
-					if fc.ready {
-						fc.ready = false
-					}
-
-					if fc.exitStatus == 0 {
-						if c := l.Check(zapcore.InfoLevel, "restarting"); c != nil {
-							c.Write(zap.String("worker", absFileName))
-						}
-
-						// a normal restart resets the backoff and failure count
-						backingOffLock.Lock()
-						backoff = minBackoff
-						failureCount = 0
-						backingOffLock.Unlock()
-						metrics.StopWorker(absFileName, StopReasonRestart)
-					} else {
-						// we will wait a few milliseconds to not overwhelm the logger in case of repeated unexpected terminations
-						if c := l.Check(zapcore.ErrorLevel, "unexpected termination, restarting"); c != nil {
-							backingOffLock.RLock()
-							c.Write(zap.String("worker", absFileName), zap.Int("failure_count", failureCount), zap.Int("exit_status", int(fc.exitStatus)), zap.Duration("waiting", backoff))
-							backingOffLock.RUnlock()
-						}
-
-						upFunc.Do(func() {
-							backingOffLock.Lock()
-							defer backingOffLock.Unlock()
-							// if we end up here, the worker has not been up for backoff*2
-							// this is probably due to a syntax error or another fatal error
-							if failureCount >= maxConsecutiveFailures {
-								panic(fmt.Errorf("workers %q: too many consecutive failures", absFileName))
-							} else {
-								failureCount += 1
-							}
-						})
-						backingOffLock.RLock()
-						wait := backoff
-						backingOffLock.RUnlock()
-						time.Sleep(wait)
-						backingOffLock.Lock()
-						backoff *= 2
-						backoff = min(backoff, maxBackoff)
-						backingOffLock.Unlock()
-						metrics.StopWorker(absFileName, StopReasonCrash)
-					}
-				} else {
-					break
-				}
-			}
-
-			metrics.StopWorker(absFileName, StopReasonShutdown)
-
-			// TODO: check if the termination is expected
-			if c := l.Check(zapcore.DebugLevel, "terminated"); c != nil {
-				c.Write(zap.String("worker", absFileName))
-			}
-		}()
+		workersReadyWG.Add(worker.num)
+		for i := 0; i < worker.num; i++ {
+			go worker.startNewWorkerThread()
+		}
 	}
 
 	workersReadyWG.Wait()
 	workersAreReady.Store(true)
-	m.Lock()
-	defer m.Unlock()
 
-	if len(errs) == 0 {
-		return nil
+	return nil
+}
+
+func newWorker(o workerOpt) (*worker, error) {
+	absFileName, err := filepath.Abs(o.fileName)
+	if err != nil {
+		return nil, fmt.Errorf("worker filename is invalid %q: %w", o.fileName, err)
 	}
 
-	return fmt.Errorf("workers %q: error while starting: %w", fileName, errors.Join(errs...))
+	// if the worker already exists, return it
+	// it's necessary since we don't want to destroy the channels when restarting on file changes
+	if w, ok := workers[absFileName]; ok {
+		return w, nil
+	}
+
+	if o.env == nil {
+		o.env = make(PreparedEnv, 1)
+	}
+
+	o.env["FRANKENPHP_WORKER\x00"] = "1"
+	w := &worker{fileName: absFileName, num: o.num, env: o.env, requestChan: make(chan *http.Request)}
+	workers[absFileName] = w
+
+	return w, nil
+}
+
+func (worker *worker) startNewWorkerThread() {
+	workerShutdownWG.Add(1)
+	defer workerShutdownWG.Done()
+
+	backoff := minWorkerErrorBackoff
+	failureCount := 0
+	backingOffLock := sync.RWMutex{}
+
+	for {
+
+		// if the worker can stay up longer than backoff*2, it is probably an application error
+		upFunc := sync.Once{}
+		go func() {
+			backingOffLock.RLock()
+			wait := backoff * 2
+			backingOffLock.RUnlock()
+			time.Sleep(wait)
+			upFunc.Do(func() {
+				backingOffLock.Lock()
+				defer backingOffLock.Unlock()
+				// if we come back to a stable state, reset the failure count
+				if backoff == minWorkerErrorBackoff {
+					failureCount = 0
+				}
+
+				// earn back the backoff over time
+				if failureCount > 0 {
+					backoff = max(backoff/2, 100*time.Millisecond)
+				}
+			})
+		}()
+
+		metrics.StartWorker(worker.fileName)
+
+		// Create main dummy request
+		r, err := http.NewRequest(http.MethodGet, filepath.Base(worker.fileName), nil)
+		if err != nil {
+			panic(err)
+		}
+
+		r, err = NewRequestWithContext(
+			r,
+			WithRequestDocumentRoot(filepath.Dir(worker.fileName), false),
+			WithRequestPreparedEnv(worker.env),
+		)
+		if err != nil {
+			panic(err)
+		}
+
+		if c := logger.Check(zapcore.DebugLevel, "starting"); c != nil {
+			c.Write(zap.String("worker", worker.fileName), zap.Int("num", worker.num))
+		}
+
+		if err := ServeHTTP(nil, r); err != nil {
+			panic(err)
+		}
+
+		fc := r.Context().Value(contextKey).(*FrankenPHPContext)
+
+		// if we are done, exit the loop that restarts the worker script
+		if workersAreDone.Load() {
+			break
+		}
+
+		// on exit status 0 we just run the worker script again
+		if fc.exitStatus == 0 {
+			// TODO: make the max restart configurable
+			if c := logger.Check(zapcore.InfoLevel, "restarting"); c != nil {
+				c.Write(zap.String("worker", worker.fileName))
+			}
+			metrics.StopWorker(worker.fileName, StopReasonRestart)
+			continue
+		}
+
+		// on exit status 1 we log the error and apply an exponential backoff when restarting
+		upFunc.Do(func() {
+			backingOffLock.Lock()
+			defer backingOffLock.Unlock()
+			// if we end up here, the worker has not been up for backoff*2
+			// this is probably due to a syntax error or another fatal error
+			if failureCount >= maxWorkerConsecutiveFailures {
+				panic(fmt.Errorf("workers %q: too many consecutive failures", worker.fileName))
+			} else {
+				failureCount += 1
+			}
+		})
+		backingOffLock.RLock()
+		wait := backoff
+		backingOffLock.RUnlock()
+		time.Sleep(wait)
+		backingOffLock.Lock()
+		backoff *= 2
+		backoff = min(backoff, maxWorkerErrorBackoff)
+		backingOffLock.Unlock()
+		metrics.StopWorker(worker.fileName, StopReasonCrash)
+	}
+
+	metrics.StopWorker(worker.fileName, StopReasonShutdown)
+
+	// TODO: check if the termination is expected
+	if c := logger.Check(zapcore.DebugLevel, "terminated"); c != nil {
+		c.Write(zap.String("worker", worker.fileName))
+	}
 }
 
 func stopWorkers() {
@@ -217,7 +195,7 @@ func drainWorkers() {
 	watcher.DrainWatcher()
 	stopWorkers()
 	workerShutdownWG.Wait()
-	workersRequestChans = sync.Map{}
+	workers = make(map[string]*worker)
 }
 
 func restartWorkersOnFileChanges(workerOpts []workerOpt) error {
@@ -249,82 +227,78 @@ func restartWorkers(workerOpts []workerOpt) {
 	logger.Info("workers restarted successfully")
 }
 
-//export go_frankenphp_worker_ready
-func go_frankenphp_worker_ready(mrh C.uintptr_t) {
-	mainRequest := cgo.Handle(mrh).Value().(*http.Request)
-	fc := mainRequest.Context().Value(contextKey).(*FrankenPHPContext)
-	fc.ready = true
+func assignThreadToWorker(thread *phpThread) {
+	fc := thread.mainRequest.Context().Value(contextKey).(*FrankenPHPContext)
 	metrics.ReadyWorker(fc.scriptFilename)
+	worker, ok := workers[fc.scriptFilename]
+	if !ok {
+		panic("worker not found for script: " + fc.scriptFilename)
+	}
+	thread.worker = worker
 	if !workersAreReady.Load() {
 		workersReadyWG.Done()
 	}
+	// TODO: we can also store all threads assigned to the worker if needed
 }
 
 //export go_frankenphp_worker_handle_request_start
-func go_frankenphp_worker_handle_request_start(mrh C.uintptr_t) C.uintptr_t {
-	mainRequest := cgo.Handle(mrh).Value().(*http.Request)
-	fc := mainRequest.Context().Value(contextKey).(*FrankenPHPContext)
+func go_frankenphp_worker_handle_request_start(threadIndex C.uintptr_t) C.bool {
+	thread := phpThreads[threadIndex]
 
-	v, ok := workersRequestChans.Load(fc.scriptFilename)
-	if !ok {
-		// Probably shutting down
-		return 0
+	// we assign a worker to the thread if it doesn't have one already
+	if thread.worker == nil {
+		assignThreadToWorker(thread)
 	}
 
-	rc := v.(chan *http.Request)
-	l := getLogger()
-
-	if c := l.Check(zapcore.DebugLevel, "waiting for request"); c != nil {
-		c.Write(zap.String("worker", fc.scriptFilename))
+	if c := logger.Check(zapcore.DebugLevel, "waiting for request"); c != nil {
+		c.Write(zap.String("worker", thread.worker.fileName))
 	}
 
 	var r *http.Request
 	select {
 	case <-workersDone:
-		if c := l.Check(zapcore.DebugLevel, "shutting down"); c != nil {
-			c.Write(zap.String("worker", fc.scriptFilename))
+		if c := logger.Check(zapcore.DebugLevel, "shutting down"); c != nil {
+			c.Write(zap.String("worker", thread.worker.fileName))
 		}
+		thread.worker = nil
 		executePHPFunction("opcache_reset")
 
-		return 0
-	case r = <-rc:
+		return C.bool(false)
+	case r = <-thread.worker.requestChan:
 	}
 
-	fc.currentWorkerRequest = cgo.NewHandle(r)
-	r.Context().Value(handleKey).(*handleList).AddHandle(fc.currentWorkerRequest)
+	thread.workerRequest = r
 
-	if c := l.Check(zapcore.DebugLevel, "request handling started"); c != nil {
-		c.Write(zap.String("worker", fc.scriptFilename), zap.String("url", r.RequestURI))
+	if c := logger.Check(zapcore.DebugLevel, "request handling started"); c != nil {
+		c.Write(zap.String("worker", thread.worker.fileName), zap.String("url", r.RequestURI))
 	}
 
-	if err := updateServerContext(r, false, mrh); err != nil {
+	if err := updateServerContext(r, false, true); err != nil {
 		// Unexpected error
-		if c := l.Check(zapcore.DebugLevel, "unexpected error"); c != nil {
-			c.Write(zap.String("worker", fc.scriptFilename), zap.String("url", r.RequestURI), zap.Error(err))
+		if c := logger.Check(zapcore.DebugLevel, "unexpected error"); c != nil {
+			c.Write(zap.String("worker", thread.worker.fileName), zap.String("url", r.RequestURI), zap.Error(err))
 		}
 
-		return 0
+		return C.bool(false)
 	}
-
-	return C.uintptr_t(fc.currentWorkerRequest)
+	return C.bool(true)
 }
 
 //export go_frankenphp_finish_request
-func go_frankenphp_finish_request(mrh, rh C.uintptr_t, deleteHandle bool) {
-	rHandle := cgo.Handle(rh)
-	r := rHandle.Value().(*http.Request)
+func go_frankenphp_finish_request(threadIndex C.uintptr_t, isWorkerRequest bool) {
+	thread := phpThreads[threadIndex]
+	r := thread.getActiveRequest()
 	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
 
-	if deleteHandle {
-		r.Context().Value(handleKey).(*handleList).FreeAll()
-		cgo.Handle(mrh).Value().(*http.Request).Context().Value(contextKey).(*FrankenPHPContext).currentWorkerRequest = 0
+	if isWorkerRequest {
+		thread.workerRequest = nil
 	}
 
 	maybeCloseContext(fc)
 
 	if c := fc.logger.Check(zapcore.DebugLevel, "request handling finished"); c != nil {
 		var fields []zap.Field
-		if mrh == 0 {
+		if isWorkerRequest {
 			fields = append(fields, zap.String("worker", fc.scriptFilename), zap.String("url", r.RequestURI))
 		} else {
 			fields = append(fields, zap.String("url", r.RequestURI))