Dispatch multiple touch events in parallel.
This change enables the input dispatcher to send multiple touch
events to an application without waiting for them to be acknowledged.
Essentially this is a variation on the old streaming optimization
but it is much more comprehensive. Event dispatch will stall as
soon as 0.5sec of unacknowledged events are accumulated or a
focused event (such as a key event) needs to be delivered.
Streaming input events makes a tremendous difference in application
performance. The next step will be to enable batching of input
events on the client side once again.
This is part of a series of changes to improve input system pipelining.
Bug: 5963420
Change-Id: I025df90c06165d719fcca7f63eed322a5cce4a78
diff --git a/libs/ui/InputTransport.cpp b/libs/ui/InputTransport.cpp
index 7047322..f7bcb68 100644
--- a/libs/ui/InputTransport.cpp
+++ b/libs/ui/InputTransport.cpp
@@ -28,6 +28,13 @@
namespace android {
+// Socket buffer size. The default is typically about 128KB, which is much larger than
+// we really need. So we make it smaller. It just needs to be big enough to hold
+// a few dozen large multi-finger motion events in the case where an application gets
+// behind processing touches.
+static const size_t SOCKET_BUFFER_SIZE = 32 * 1024;
+
+
// --- InputMessage ---
bool InputMessage::isValid(size_t actualSize) const {
@@ -93,6 +100,12 @@
return result;
}
+ int bufferSize = SOCKET_BUFFER_SIZE;
+ setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
+ setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
+ setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
+ setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
+
String8 serverChannelName = name;
serverChannelName.append(" (server)");
outServerChannel = new InputChannel(serverChannelName, sockets[0]);