LocalServices: Replace ArrayMap with HashMap for performance

kdrag0n · kdrag0n · commit 5474e805e51f · 2021-10-16T05:58:26.000-07:00
When opening and closing activities in Settings, a significant amount of CPU time is spent looking up ArrayMap entries, as reported by simpleperf: 0.12% /system/framework/arm64/boot-framework.oat android.util.ArrayMap.binarySearchHashes LocalServices is responsible for a significant portion of the time spent in ArrayMap lookups: 0.08% 0.08% /system/framework/arm64/boot-framework.oat android.util.ArrayMap.binarySearchHashes | -- android.util.ArrayMap.binarySearchHashes | --50.00%-- android.util.ArrayMap.indexOf | |--36.71%-- android.util.ArrayMap.get | |--0.87%-- [hit in function] | | | |--6.12%-- com.android.server.LocalServices.getService | | | | | |--42.41%-- com.android.server.inputmethod.InputMethodManagerInternal.get [DEDUPED] | | | com.android.server.wm.-$$Lambda$DisplayContent$-xtu90EUfC_AM8Qe5g8vDDI07_E.run | | | android.os.Handler.dispatchMessage | | | android.os.Looper.loop | | | android.os.HandlerThread.run | | | com.android.server.ServiceThread.run | | | art_quick_invoke_stub | | | art::ArtMethod::Invoke(art::Thread*, unsigned int*, unsigned int, art::JValue*, char const*) | | | art::JValue art::InvokeVirtualOrInterfaceWithJValues<art::ArtMethod*>(art::ScopedObjectAccessAlreadyRunnable const&, _jobject*, art::ArtMethod*, jvalue const*) | | | art::Thread::CreateCallback(void*) | | | __pthread_start(void*) | | | __start_thread | | | | | |--36.66%-- com.android.server.notification.NotificationManagerService.enqueueNotificationInternal | | | com.android.server.notification.NotificationManagerService.enqueueNotificationInternal | | | com.android.server.notification.NotificationManagerService$10.enqueueNotificationWithTag | | | android.app.INotificationManager$Stub.onTransact | | | android.os.Binder.execTransactInternal | | | android.os.Binder.execTransact | | | art_quick_invoke_stub | | | art::ArtMethod::Invoke(art::Thread*, unsigned int*, unsigned int, art::JValue*, char const*) | | | art::JValue art::InvokeVirtualOrInterfaceWithVarArgs<art::ArtMethod*>(art::ScopedObjectAccessAlreadyRunnable const&, _jobject*, art::ArtMethod*, std::__va_list) | | | art::JValue art::InvokeVirtualOrInterfaceWithVarArgs<_jmethodID*>(art::ScopedObjectAccessAlreadyRunnable const&, _jobject*, _jmethodID*, std::__va_list) | | | art::JNI<false>::CallBooleanMethodV(_JNIEnv*, _jobject*, _jmethodID*, std::__va_list) | | | _JNIEnv::CallBooleanMethod(_jobject*, _jmethodID*, ...) | | | JavaBBinder::onTransact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int) | | | android::BBinder::transact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int) | | | android::IPCThreadState::executeCommand(int) | | | android::IPCThreadState::getAndExecuteCommand() | | | android::IPCThreadState::joinThreadPool(bool) | | | android::PoolThread::threadLoop() | | | android::Thread::_threadLoop(void*) | | | android::AndroidRuntime::javaThreadShell(void*) | | | thread_data_t::trampoline(thread_data_t const*) | | | __pthread_start(void*) | | | __start_thread | | | | | --20.93%-- com.android.server.oemlock.OemLockService.setPersistentDataBlockOemUnlockAllowedBit | | com.android.server.oemlock.OemLockService$2.isOemUnlockAllowed | | android.service.oemlock.IOemLockService$Stub.onTransact | | android.os.Binder.execTransactInternal | | android.os.Binder.execTransact | | art_quick_invoke_stub | | art::ArtMethod::Invoke(art::Thread*, unsigned int*, unsigned int, art::JValue*, char const*) | | art::JValue art::InvokeVirtualOrInterfaceWithVarArgs<art::ArtMethod*>(art::ScopedObjectAccessAlreadyRunnable const&, _jobject*, art::ArtMethod*, std::__va_list) | | art::JValue art::InvokeVirtualOrInterfaceWithVarArgs<_jmethodID*>(art::ScopedObjectAccessAlreadyRunnable const&, _jobject*, _jmethodID*, std::__va_list) | | art::JNI<false>::CallBooleanMethodV(_JNIEnv*, _jobject*, _jmethodID*, std::__va_list) | | _JNIEnv::CallBooleanMethod(_jobject*, _jmethodID*, ...) | | JavaBBinder::onTransact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int) | | android::BBinder::transact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int) | | android::IPCThreadState::executeCommand(int) | | android::IPCThreadState::getAndExecuteCommand() | | android::IPCThreadState::joinThreadPool(bool) | | android::PoolThread::threadLoop() | | android::Thread::_threadLoop(void*) | | android::AndroidRuntime::javaThreadShell(void*) | | thread_data_t::trampoline(thread_data_t const*) | | __pthread_start(void*) | | __start_thread Empirical testing reveals that sLocalServiceObjects usually contains 68 entries, at which HashMap is 47% faster than ArrayMap for lookups and 68% faster [1] for insertions. The increased memory usage should be negligible at this size, so we can safely convert the map to a HashMap in order to improve performance in this hotpath. [1] https://docs.google.com/spreadsheets/d/136UJS2yVlZyPx30KDNgj4AWldkp9xbzIcWkLFj9RGgk/edit Test: simpleperf record -a; verify that LocalServices no longer appears under ArrayMap.binarySearchHashes Change-Id: Ifd1f8b7940eba7723f93a73456470a84d34656ae
diff --git a/core/java/com/android/server/LocalServices.java b/core/java/com/android/server/LocalServices.java
@@ -18,7 +18,7 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 
-import android.util.ArrayMap;
+import java.util.HashMap;
 
 /**
  * This class is used in a similar way as ServiceManager, except the services registered here
@@ -32,8 +32,8 @@
 public final class LocalServices {
     private LocalServices() {}
 
-    private static final ArrayMap<Class<?>, Object> sLocalServiceObjects =
-            new ArrayMap<Class<?>, Object>();
+    private static final HashMap<Class<?>, Object> sLocalServiceObjects =
+            new HashMap<Class<?>, Object>();
 
     /**
      * Returns a local service instance that implements the specified interface.
