1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.internal.os; 18 19 import android.annotation.Nullable; 20 import android.os.SystemClock; 21 import android.util.Slog; 22 23 /** 24 * The base class of all KernelUidCpuTimeReaders. 25 * 26 * This class is NOT designed to be thread-safe or accessed by more than one caller (due to 27 * the nature of {@link #readDelta(Callback)}). 28 */ 29 public abstract class KernelUidCpuTimeReaderBase<T extends KernelUidCpuTimeReaderBase.Callback> { 30 protected static final boolean DEBUG = false; 31 // Throttle interval in milliseconds 32 private static final long DEFAULT_THROTTLE_INTERVAL = 10_000L; 33 34 private final String TAG = this.getClass().getSimpleName(); 35 private long mLastTimeReadMs = Long.MIN_VALUE; 36 private long mThrottleInterval = DEFAULT_THROTTLE_INTERVAL; 37 38 // A generic Callback interface (used by readDelta) to be extended by subclasses. 39 public interface Callback { 40 } 41 42 public void readDelta(@Nullable T cb) { 43 if (SystemClock.elapsedRealtime() < mLastTimeReadMs + mThrottleInterval) { 44 if (DEBUG) { 45 Slog.d(TAG, "Throttle"); 46 } 47 return; 48 } 49 readDeltaImpl(cb); 50 mLastTimeReadMs = SystemClock.elapsedRealtime(); 51 } 52 53 protected abstract void readDeltaImpl(@Nullable T cb); 54 55 public void setThrottleInterval(long throttleInterval) { 56 if (throttleInterval >= 0) { 57 mThrottleInterval = throttleInterval; 58 } 59 } 60 } 61
