Optimization: Restrict signing to ACTION_UP and ACTION_DOWN while doing a motion gesture such as scrolling apps
Savings. ~2.5% of total system_server time while scrolling on apps drawer screen.
Baseline:
https://pprof.corp.google.com/?id=732307aa60aa82bf478b0c3f0e6de6be&ignore=sendMessage
https://screenshot.googleplex.com/JpWt25tXRJO
Optimized:
https://pprof.corp.google.com/?id=5040d255411f407662a7f2da0109ca48&ignore=sendMessage
https://screenshot.googleplex.com/x81k7vUUKdd
Test: atest inputflinger_tests
Change-Id: I52dd33f8203fe62bfcbde7be5a1ac45c46064585
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 26b3be6..04a47e7 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -364,18 +364,16 @@
break;
}
}
- std::vector<uint8_t> data;
const uint8_t* start = reinterpret_cast<const uint8_t*>(&event);
- data.assign(start, start + size);
- return sign(data);
+ return sign(start, size);
}
-std::array<uint8_t, 32> HmacKeyManager::sign(const std::vector<uint8_t>& data) const {
+std::array<uint8_t, 32> HmacKeyManager::sign(const uint8_t* data, size_t size) const {
// SHA256 always generates 32-bytes result
std::array<uint8_t, 32> hash;
unsigned int hashLen = 0;
- uint8_t* result = HMAC(EVP_sha256(), mHmacKey.data(), mHmacKey.size(), data.data(), data.size(),
- hash.data(), &hashLen);
+ uint8_t* result =
+ HMAC(EVP_sha256(), mHmacKey.data(), mHmacKey.size(), data, size, hash.data(), &hashLen);
if (result == nullptr) {
ALOGE("Could not sign the data using HMAC");
return INVALID_HMAC;
@@ -2444,11 +2442,8 @@
EventEntry* eventEntry = dispatchEntry->eventEntry;
switch (eventEntry->type) {
case EventEntry::Type::KEY: {
- KeyEntry* keyEntry = static_cast<KeyEntry*>(eventEntry);
- VerifiedKeyEvent verifiedEvent = verifiedKeyEventFromKeyEntry(*keyEntry);
- verifiedEvent.flags = dispatchEntry->resolvedFlags & VERIFIED_KEY_EVENT_FLAGS;
- verifiedEvent.action = dispatchEntry->resolvedAction;
- std::array<uint8_t, 32> hmac = mHmacKeyManager.sign(verifiedEvent);
+ const KeyEntry* keyEntry = static_cast<KeyEntry*>(eventEntry);
+ std::array<uint8_t, 32> hmac = getSignature(*keyEntry, *dispatchEntry);
// Publish the key event.
status =
@@ -2500,12 +2495,8 @@
usingCoords = scaledCoords;
}
}
- VerifiedMotionEvent verifiedEvent =
- verifiedMotionEventFromMotionEntry(*motionEntry);
- verifiedEvent.actionMasked =
- dispatchEntry->resolvedAction & AMOTION_EVENT_ACTION_MASK;
- verifiedEvent.flags = dispatchEntry->resolvedFlags & VERIFIED_MOTION_EVENT_FLAGS;
- std::array<uint8_t, 32> hmac = mHmacKeyManager.sign(verifiedEvent);
+
+ std::array<uint8_t, 32> hmac = getSignature(*motionEntry, *dispatchEntry);
// Publish the motion event.
status = connection->inputPublisher
@@ -2585,6 +2576,28 @@
}
}
+const std::array<uint8_t, 32> InputDispatcher::getSignature(
+ const MotionEntry& motionEntry, const DispatchEntry& dispatchEntry) const {
+ int32_t actionMasked = dispatchEntry.resolvedAction & AMOTION_EVENT_ACTION_MASK;
+ if ((actionMasked == AMOTION_EVENT_ACTION_UP) || (actionMasked == AMOTION_EVENT_ACTION_DOWN)) {
+ // Only sign events up and down events as the purely move events
+ // are tied to their up/down counterparts so signing would be redundant.
+ VerifiedMotionEvent verifiedEvent = verifiedMotionEventFromMotionEntry(motionEntry);
+ verifiedEvent.actionMasked = actionMasked;
+ verifiedEvent.flags = dispatchEntry.resolvedFlags & VERIFIED_MOTION_EVENT_FLAGS;
+ return mHmacKeyManager.sign(verifiedEvent);
+ }
+ return INVALID_HMAC;
+}
+
+const std::array<uint8_t, 32> InputDispatcher::getSignature(
+ const KeyEntry& keyEntry, const DispatchEntry& dispatchEntry) const {
+ VerifiedKeyEvent verifiedEvent = verifiedKeyEventFromKeyEntry(keyEntry);
+ verifiedEvent.flags = dispatchEntry.resolvedFlags & VERIFIED_KEY_EVENT_FLAGS;
+ verifiedEvent.action = dispatchEntry.resolvedAction;
+ return mHmacKeyManager.sign(verifiedEvent);
+}
+
void InputDispatcher::finishDispatchCycleLocked(nsecs_t currentTime,
const sp<Connection>& connection, uint32_t seq,
bool handled) {