Read up to 8 InterruptMessages at a time, in unix eventhandlers.

runtime/bin/eventhandler_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/eventhandler.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 166 matching lines @@
   if (result != kInterruptMessageSize) {
     if (result == -1) {
       perror("Interrupt message failure:");
     }
     FATAL1("Interrupt message failure. Wrote %" Pd " bytes.", result);
   }
 }
 
 
 void EventHandlerImplementation::HandleInterruptFd() {
-  InterruptMessage msg;
-  intptr_t available = FDUtils::AvailableBytes(interrupt_fds_[0]);
-  for (int i = 0;
-       i + kInterruptMessageSize <= available;
-       i += kInterruptMessageSize) {
-    VOID_TEMP_FAILURE_RETRY(read(interrupt_fds_[0],
-                                 reinterpret_cast<char*>(&msg),
-                                 kInterruptMessageSize));
-    if (msg.id == kTimerId) {
-      timeout_queue_.UpdateTimeout(msg.dart_port, msg.data);
-    } else if (msg.id == kShutdownId) {
+  const intptr_t BUFFER_SIZE = 8 * kInterruptMessageSize;
+  char buffer[BUFFER_SIZE];
+  ssize_t bytes = TEMP_FAILURE_RETRY(read(interrupt_fds_[0],
+                                          buffer,
+                                          BUFFER_SIZE));
+  for (ssize_t i = 0; i < bytes / kInterruptMessageSize; i++) {
+    InterruptMessage* msg = reinterpret_cast<InterruptMessage*>(
+        buffer + i * kInterruptMessageSize);
+    if (msg->id == kTimerId) {
+      timeout_queue_.UpdateTimeout(msg->dart_port, msg->data);
+    } else if (msg->id == kShutdownId) {
       shutdown_ = true;
     } else {
-      SocketData* sd = GetSocketData(msg.id);
-      if ((msg.data & (1 << kShutdownReadCommand)) != 0) {
-        ASSERT(msg.data == (1 << kShutdownReadCommand));
+      SocketData* sd = GetSocketData(msg->id);
+      if ((msg->data & (1 << kShutdownReadCommand)) != 0) {
+        ASSERT(msg->data == (1 << kShutdownReadCommand));
         // Close the socket for reading.
         sd->ShutdownRead();
         UpdateEpollInstance(epoll_fd_, sd);
-      } else if ((msg.data & (1 << kShutdownWriteCommand)) != 0) {
-        ASSERT(msg.data == (1 << kShutdownWriteCommand));
+      } else if ((msg->data & (1 << kShutdownWriteCommand)) != 0) {
+        ASSERT(msg->data == (1 << kShutdownWriteCommand));
         // Close the socket for writing.
         sd->ShutdownWrite();
         UpdateEpollInstance(epoll_fd_, sd);
-      } else if ((msg.data & (1 << kCloseCommand)) != 0) {
-        ASSERT(msg.data == (1 << kCloseCommand));
+      } else if ((msg->data & (1 << kCloseCommand)) != 0) {
+        ASSERT(msg->data == (1 << kCloseCommand));
         // Close the socket and free system resources and move on to
         // next message.
         RemoveFromEpollInstance(epoll_fd_, sd);
         intptr_t fd = sd->fd();
         if (fd == STDOUT_FILENO) {
           // If stdout, redirect fd to /dev/null.
           int null_fd = TEMP_FAILURE_RETRY(open("/dev/null", O_WRONLY));
           ASSERT(null_fd >= 0);
           VOID_TEMP_FAILURE_RETRY(dup2(null_fd, STDOUT_FILENO));
           VOID_TEMP_FAILURE_RETRY(close(null_fd));
         } else {
           sd->Close();
         }
         socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
         delete sd;
-        DartUtils::PostInt32(msg.dart_port, 1 << kDestroyedEvent);
+        DartUtils::PostInt32(msg->dart_port, 1 << kDestroyedEvent);
       } else {
-        if ((msg.data & (1 << kInEvent)) != 0 && sd->IsClosedRead()) {
-          DartUtils::PostInt32(msg.dart_port, 1 << kCloseEvent);
+        if ((msg->data & (1 << kInEvent)) != 0 && sd->IsClosedRead()) {
+          DartUtils::PostInt32(msg->dart_port, 1 << kCloseEvent);
         } else {
           // Setup events to wait for.
-          sd->SetPortAndMask(msg.dart_port, msg.data);
+          sd->SetPortAndMask(msg->dart_port, msg->data);
           UpdateEpollInstance(epoll_fd_, sd);
         }
       }
     }
   }
 }
 
 #ifdef DEBUG_POLL
 static void PrintEventMask(intptr_t fd, intptr_t events) {
   Log::Print("%d ", fd);
@@ skipping 195 matching lines @@
 
 uint32_t EventHandlerImplementation::GetHashmapHashFromFd(intptr_t fd) {
   // The hashmap does not support keys with value 0.
   return dart::Utils::WordHash(fd + 1);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)