Optimize EventHub reads.
Change-Id: Id7d09c0a6e5c741c1e29becd2b6560772c5ff372
diff --git a/include/ui/EventHub.h b/include/ui/EventHub.h
index dab35b3..3132941 100644
--- a/include/ui/EventHub.h
+++ b/include/ui/EventHub.h
@@ -266,6 +266,12 @@
#ifdef EV_SW
int32_t mSwitches[SW_MAX + 1];
#endif
+
+ static const int INPUT_BUFFER_SIZE = 64;
+ struct input_event mInputBufferData[INPUT_BUFFER_SIZE];
+ int32_t mInputBufferIndex;
+ int32_t mInputBufferCount;
+ int32_t mInputDeviceIndex;
};
}; // namespace android
diff --git a/libs/ui/EventHub.cpp b/libs/ui/EventHub.cpp
index 124f7b3..33393fe 100644
--- a/libs/ui/EventHub.cpp
+++ b/libs/ui/EventHub.cpp
@@ -100,6 +100,7 @@
, mDevicesById(0), mNumDevicesById(0)
, mOpeningDevices(0), mClosingDevices(0)
, mDevices(0), mFDs(0), mFDCount(0), mOpened(false)
+ , mInputBufferIndex(0), mInputBufferCount(0), mInputDeviceIndex(0)
{
acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);
#ifdef EV_SW
@@ -343,13 +344,6 @@
outEvent->value = 0;
outEvent->when = 0;
- status_t err;
-
- int i;
- int res;
- int pollres;
- struct input_event iev;
-
// Note that we only allow one caller to getEvent(), so don't need
// to do locking here... only when adding/removing devices.
@@ -358,9 +352,8 @@
mOpened = true;
}
- while(1) {
-
- // First, report any devices that had last been added/removed.
+ for (;;) {
+ // Report any devices that had last been added/removed.
if (mClosingDevices != NULL) {
device_t* device = mClosingDevices;
LOGV("Reporting device closed: id=0x%x, name=%s\n",
@@ -390,77 +383,96 @@
return true;
}
- release_wake_lock(WAKE_LOCK_ID);
+ // Grab the next input event.
+ for (;;) {
+ // Consume buffered input events, if any.
+ if (mInputBufferIndex < mInputBufferCount) {
+ const struct input_event& iev = mInputBufferData[mInputBufferIndex++];
+ const device_t* device = mDevices[mInputDeviceIndex];
- pollres = poll(mFDs, mFDCount, -1);
-
- acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);
-
- if (pollres <= 0) {
- if (errno != EINTR) {
- LOGW("select failed (errno=%d)\n", errno);
- usleep(100000);
- }
- continue;
- }
-
- //printf("poll %d, returned %d\n", mFDCount, pollres);
-
- // mFDs[0] is used for inotify, so process regular events starting at mFDs[1]
- for(i = 1; i < mFDCount; i++) {
- if(mFDs[i].revents) {
- LOGV("revents for %d = 0x%08x", i, mFDs[i].revents);
- if(mFDs[i].revents & POLLIN) {
- res = read(mFDs[i].fd, &iev, sizeof(iev));
- if (res == sizeof(iev)) {
- device_t* device = mDevices[i];
- LOGV("%s got: t0=%d, t1=%d, type=%d, code=%d, v=%d",
- device->path.string(),
- (int) iev.time.tv_sec, (int) iev.time.tv_usec,
- iev.type, iev.code, iev.value);
- if (device->id == mFirstKeyboardId) {
- outEvent->deviceId = 0;
- } else {
- outEvent->deviceId = device->id;
- }
- outEvent->type = iev.type;
- outEvent->scanCode = iev.code;
- if (iev.type == EV_KEY) {
- err = device->layoutMap->map(iev.code,
- & outEvent->keyCode, & outEvent->flags);
- LOGV("iev.code=%d keyCode=%d flags=0x%08x err=%d\n",
- iev.code, outEvent->keyCode, outEvent->flags, err);
- if (err != 0) {
- outEvent->keyCode = AKEYCODE_UNKNOWN;
- outEvent->flags = 0;
- }
- } else {
- outEvent->keyCode = iev.code;
- }
- outEvent->value = iev.value;
-
- // Use an event timestamp in the same timebase as
- // java.lang.System.nanoTime() and android.os.SystemClock.uptimeMillis()
- // as expected by the rest of the system.
- outEvent->when = systemTime(SYSTEM_TIME_MONOTONIC);
- return true;
- } else {
- if (res<0) {
- LOGW("could not get event (errno=%d)", errno);
- } else {
- LOGE("could not get event (wrong size: %d)", res);
- }
- continue;
+ LOGV("%s got: t0=%d, t1=%d, type=%d, code=%d, v=%d", device->path.string(),
+ (int) iev.time.tv_sec, (int) iev.time.tv_usec, iev.type, iev.code, iev.value);
+ if (device->id == mFirstKeyboardId) {
+ outEvent->deviceId = 0;
+ } else {
+ outEvent->deviceId = device->id;
+ }
+ outEvent->type = iev.type;
+ outEvent->scanCode = iev.code;
+ if (iev.type == EV_KEY) {
+ status_t err = device->layoutMap->map(iev.code,
+ & outEvent->keyCode, & outEvent->flags);
+ LOGV("iev.code=%d keyCode=%d flags=0x%08x err=%d\n",
+ iev.code, outEvent->keyCode, outEvent->flags, err);
+ if (err != 0) {
+ outEvent->keyCode = AKEYCODE_UNKNOWN;
+ outEvent->flags = 0;
}
+ } else {
+ outEvent->keyCode = iev.code;
+ }
+ outEvent->value = iev.value;
+
+ // Use an event timestamp in the same timebase as
+ // java.lang.System.nanoTime() and android.os.SystemClock.uptimeMillis()
+ // as expected by the rest of the system.
+ outEvent->when = systemTime(SYSTEM_TIME_MONOTONIC);
+ return true;
+ }
+
+ // Finish reading all events from devices identified in previous poll().
+ // This code assumes that mInputDeviceIndex is initially 0 and that the
+ // revents member of pollfd is initialized to 0 when the device is first added.
+ // Since mFDs[0] is used for inotify, we process regular events starting at index 1.
+ mInputDeviceIndex += 1;
+ if (mInputDeviceIndex >= mFDCount) {
+ mInputDeviceIndex = 0;
+ break;
+ }
+
+ const struct pollfd &pfd = mFDs[mInputDeviceIndex];
+ if (pfd.revents & POLLIN) {
+ int32_t readSize = read(pfd.fd, mInputBufferData,
+ sizeof(struct input_event) * INPUT_BUFFER_SIZE);
+ if (readSize < 0) {
+ if (errno != EAGAIN && errno != EINTR) {
+ LOGW("could not get event (errno=%d)", errno);
+ }
+ } else if ((readSize % sizeof(struct input_event)) != 0) {
+ LOGE("could not get event (wrong size: %d)", readSize);
+ } else {
+ mInputBufferCount = readSize / sizeof(struct input_event);
+ mInputBufferIndex = 0;
}
}
}
-
+
// read_notify() will modify mFDs and mFDCount, so this must be done after
// processing all other events.
if(mFDs[0].revents & POLLIN) {
read_notify(mFDs[0].fd);
}
+
+ // Poll for events. Mind the wake lock dance!
+ // We hold a wake lock at all times except during poll(). This works due to some
+ // subtle choreography. When a device driver has pending (unread) events, it acquires
+ // a kernel wake lock. However, once the last pending event has been read, the device
+ // driver will release the kernel wake lock. To prevent the system from going to sleep
+ // when this happens, the EventHub holds onto its own user wake lock while the client
+ // is processing events. Thus the system can only sleep if there are no events
+ // pending or currently being processed.
+ release_wake_lock(WAKE_LOCK_ID);
+
+ int pollResult = poll(mFDs, mFDCount, -1);
+
+ acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);
+
+ if (pollResult <= 0) {
+ if (errno != EINTR) {
+ LOGW("select failed (errno=%d)\n", errno);
+ usleep(100000);
+ }
+ }
}
}
@@ -478,6 +490,7 @@
mFDs = (pollfd *)calloc(1, sizeof(mFDs[0]));
mDevices = (device_t **)calloc(1, sizeof(mDevices[0]));
mFDs[0].events = POLLIN;
+ mFDs[0].revents = 0;
mDevices[0] = NULL;
#ifdef HAVE_INOTIFY
mFDs[0].fd = inotify_init();
@@ -584,6 +597,12 @@
idstr[0] = '\0';
}
+ if (fcntl(fd, F_SETFL, O_NONBLOCK)) {
+ LOGE("Error %d making device file descriptor non-blocking.", errno);
+ close(fd);
+ return -1;
+ }
+
int devid = 0;
while (devid < mNumDevicesById) {
if (mDevicesById[devid].device == NULL) {
@@ -640,6 +659,7 @@
mFDs[mFDCount].fd = fd;
mFDs[mFDCount].events = POLLIN;
+ mFDs[mFDCount].revents = 0;
// Figure out the kinds of events the device reports.
