From 5ced76a14350db56f1a80f00076f8be3d982c389 Mon Sep 17 00:00:00 2001 From: Jeff Brown Date: Tue, 24 May 2011 11:23:27 -0700 Subject: Coalesce input events that arrive faster than 333Hz. (DO NOT MERGE) Some drivers report individual finger updates one at a time instead of all at once. When 10 fingers are down, this can cause the framework to have to handle 10 times as many events each with 10 times as much data. Applications like PointerLocation would get significantly bogged down by all of the redundant samples. This change coalesces samples that are closely spaced in time, before they are dispatched, as part of the motion event batching protocol. Increased the size of the InputChannel shared memory buffer so that applications can catch up faster if they accumulate a backlog of samples. Change-Id: Ibc6abf8af027d9003011ac75caa12941080caba3 --- services/input/EventHub.cpp | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'services/input/EventHub.cpp') diff --git a/services/input/EventHub.cpp b/services/input/EventHub.cpp index 7625adb14108..d80abe895b5f 100644 --- a/services/input/EventHub.cpp +++ b/services/input/EventHub.cpp @@ -539,7 +539,24 @@ size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSiz (int) iev.time.tv_sec, (int) iev.time.tv_usec, iev.type, iev.code, iev.value); +#ifdef HAVE_POSIX_CLOCKS + // Use the time specified in the event instead of the current time + // so that downstream code can get more accurate estimates of + // event dispatch latency from the time the event is enqueued onto + // the evdev client buffer. + // + // The event's timestamp fortuitously uses the same monotonic clock + // time base as the rest of Android. The kernel event device driver + // (drivers/input/evdev.c) obtains timestamps using ktime_get_ts(). + // The systemTime(SYSTEM_TIME_MONOTONIC) function we use everywhere + // calls clock_gettime(CLOCK_MONOTONIC) which is implemented as a + // system call that also queries ktime_get_ts(). + event->when = nsecs_t(iev.time.tv_sec) * 1000000000LL + + nsecs_t(iev.time.tv_usec) * 1000LL; + LOGV("event time %lld, now %lld", event->when, now); +#else event->when = now; +#endif event->deviceId = deviceId; event->type = iev.type; event->scanCode = iev.code; -- cgit v1.2.3-59-g8ed1b