From 88e8d72a75b31618576039c9376150a4dbadf339 Mon Sep 17 00:00:00 2001 From: Jeff Sharkey Date: Wed, 4 Nov 2020 20:42:55 -0700 Subject: [PATCH] Double speed of Parcel.writeString(). Previous logic was using GetStringUTFChars() and GetStringCritical(), which resulted in making a new temporary heap allocation and an extra memcpy(). The new approach in this CL bypasses those operations by asking the JNI helpers to copy directly into the Parcel buffer. This does mean that the contract for writing strings (prefixed with length) is now duplicated in Parcel.cpp and android_os_Parcel.cpp, so we leave docs to ensure future maintainers keep them in sync. Benchmarking shows that this change improves performance by ~36% for UTF-8 strings and ~52% for UTF-16 strings: Before: timeWriteString8[simple]_mean: 1323 timeWriteString8[complex]_mean: 2103 timeWriteString16[simple]_mean: 1427 timeWriteString16[complex]_mean: 1368 After: timeWriteString8[simple]_mean: 846 timeWriteString8[complex]_mean: 1671 timeWriteString16[simple]_mean: 685 timeWriteString16[complex]_mean: 748 Bug: 172562452 Test: atest CorePerfTests:android.os.ParcelStringPerfTest Change-Id: Ibacce2547ecc7a050b698cee8aa5b4e3bc45956f --- .../src/android/os/ParcelStringPerfTest.java | 70 +++++++++++++++++++ core/jni/android_os_Parcel.cpp | 51 ++++++++------ 2 files changed, 100 insertions(+), 21 deletions(-) create mode 100644 apct-tests/perftests/core/src/android/os/ParcelStringPerfTest.java diff --git a/apct-tests/perftests/core/src/android/os/ParcelStringPerfTest.java b/apct-tests/perftests/core/src/android/os/ParcelStringPerfTest.java new file mode 100644 index 0000000000000..2b861cb668909 --- /dev/null +++ b/apct-tests/perftests/core/src/android/os/ParcelStringPerfTest.java @@ -0,0 +1,70 @@ +/* + * Copyright (C) 2020 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package android.os; + +import android.perftests.utils.BenchmarkState; +import android.perftests.utils.PerfStatusReporter; + +import androidx.test.filters.LargeTest; + +import org.junit.Rule; +import org.junit.Test; +import org.junit.runner.RunWith; +import org.junit.runners.Parameterized; + +import java.util.Arrays; +import java.util.Collection; + +@LargeTest +@RunWith(Parameterized.class) +public class ParcelStringPerfTest { + @Rule + public PerfStatusReporter mPerfStatusReporter = new PerfStatusReporter(); + + @Parameterized.Parameter(0) + public String mName; + @Parameterized.Parameter(1) + public String mValue; + + @Parameterized.Parameters(name = "{0}") + public static Collection getParameters() { + return Arrays.asList(new Object[][] { + { "simple", "com.example.typical_package_name" }, + { "complex", "從不喜歡孤單一個 - 蘇永康／吳雨霏" }, + }); + } + + @Test + public void timeWriteString8() { + final Parcel parcel = Parcel.obtain(); + final BenchmarkState state = mPerfStatusReporter.getBenchmarkState(); + while (state.keepRunning()) { + parcel.setDataPosition(0); + parcel.writeString8(mValue); + } + } + + @Test + public void timeWriteString16() { + final Parcel parcel = Parcel.obtain(); + final BenchmarkState state = mPerfStatusReporter.getBenchmarkState(); + while (state.keepRunning()) { + parcel.setDataPosition(0); + parcel.writeString16(mValue); + } + } +} diff --git a/core/jni/android_os_Parcel.cpp b/core/jni/android_os_Parcel.cpp index 355ef0cd6b3f9..f05c6a42c5f72 100644 --- a/core/jni/android_os_Parcel.cpp +++ b/core/jni/android_os_Parcel.cpp @@ -252,20 +252,25 @@ static void android_os_Parcel_nativeSignalExceptionForError(JNIEnv* env, jclass signalExceptionForError(env, clazz, err); } -static void android_os_Parcel_writeString8(JNIEnv* env, jclass clazz, jlong nativePtr, jstring val) -{ +static void android_os_Parcel_writeString8(JNIEnv *env, jclass clazz, jlong nativePtr, + jstring val) { Parcel* parcel = reinterpret_cast(nativePtr); - if (parcel != NULL) { - status_t err = NO_MEMORY; + if (parcel != nullptr) { + status_t err = NO_ERROR; if (val) { - const size_t len = env->GetStringUTFLength(val); - const char* str = env->GetStringUTFChars(val, 0); - if (str) { - err = parcel->writeString8(str, len); - env->ReleaseStringUTFChars(val, str); + // NOTE: Keep this logic in sync with Parcel.cpp + const size_t len = env->GetStringLength(val); + const size_t allocLen = env->GetStringUTFLength(val); + err = parcel->writeInt32(allocLen); + char *data = reinterpret_cast(parcel->writeInplace(allocLen + sizeof(char))); + if (data != nullptr) { + env->GetStringUTFRegion(val, 0, len, data); + *(data + allocLen) = 0; + } else { + err = NO_MEMORY; } } else { - err = parcel->writeString8(NULL, 0); + err = parcel->writeString8(nullptr, 0); } if (err != NO_ERROR) { signalExceptionForError(env, clazz, err); @@ -273,21 +278,25 @@ static void android_os_Parcel_writeString8(JNIEnv* env, jclass clazz, jlong nati } } -static void android_os_Parcel_writeString16(JNIEnv* env, jclass clazz, jlong nativePtr, jstring val) -{ +static void android_os_Parcel_writeString16(JNIEnv *env, jclass clazz, jlong nativePtr, + jstring val) { Parcel* parcel = reinterpret_cast(nativePtr); - if (parcel != NULL) { - status_t err = NO_MEMORY; + if (parcel != nullptr) { + status_t err = NO_ERROR; if (val) { - const jchar* str = env->GetStringCritical(val, 0); - if (str) { - err = parcel->writeString16( - reinterpret_cast(str), - env->GetStringLength(val)); - env->ReleaseStringCritical(val, str); + // NOTE: Keep this logic in sync with Parcel.cpp + const size_t len = env->GetStringLength(val); + const size_t allocLen = len * sizeof(char16_t); + err = parcel->writeInt32(len); + char *data = reinterpret_cast(parcel->writeInplace(allocLen + sizeof(char16_t))); + if (data != nullptr) { + env->GetStringRegion(val, 0, len, reinterpret_cast(data)); + *reinterpret_cast(data + allocLen) = 0; + } else { + err = NO_MEMORY; } } else { - err = parcel->writeString16(NULL, 0); + err = parcel->writeString16(nullptr, 0); } if (err != NO_ERROR) { signalExceptionForError(env, clazz, err);