Android P CPU 升频

Android P CPU 升频"/>

Android P CPU 升频

CPU 升频

不经意间发现一段有趣的代码，看了注释是可以直接根据CPU群簇进行同时升频率，即例如8核，同时拉高最高频率，字符串命令格式“0:1900800/4:2500000”

/** Copyright (C) 2017 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**      .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 com.android.server.power.batterysaver;import android.util.ArrayMap;
import android.util.Slog;import com.android.internal.annotations.GuardedBy;import java.util.Map;/*** Helper to parse a list of "core-number:frequency" pairs concatenated with / as a separator,* and convert them into a map of "filename -> value" that should be written to* /sys/.../scaling_max_freq.** Example input: "0:1900800/4:2500000", which will be converted into:*   "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" "1900800"*   "/sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq" "2500000"** Test:atest $ANDROID_BUILD_TOP/frameworks/base/services/tests/servicestests/src/com/android/server/power/batterysaver/CpuFrequenciesTest.java*/
public class CpuFrequencies {private static final String TAG = "CpuFrequencies";private final Object mLock = new Object();@GuardedBy("mLock")private final ArrayMap<Integer, Long> mCoreAndFrequencies = new ArrayMap<>();public CpuFrequencies() {}/*** Parse a string.*/public CpuFrequencies parseString(String cpuNumberAndFrequencies) {synchronized (mLock) {mCoreAndFrequencies.clear();try {for (String pair : cpuNumberAndFrequencies.split("/")) {pair = pair.trim();if (pair.length() == 0) {continue;}final String[] coreAndFreq = pair.split(":", 2);if (coreAndFreq.length != 2) {throw new IllegalArgumentException("Wrong format");}final int core = Integer.parseInt(coreAndFreq[0]);final long freq = Long.parseLong(coreAndFreq[1]);mCoreAndFrequencies.put(core, freq);}} catch (IllegalArgumentException e) {Slog.wtf(TAG, "Invalid configuration: '" + cpuNumberAndFrequencies + "'");}}return this;}/*** Return a new map containing the filename-value pairs.*/public ArrayMap<String, String> toSysFileMap() {final ArrayMap<String, String> map = new ArrayMap<>();addToSysFileMap(map);return map;}/*** Add the filename-value pairs to an existing map.*/public void addToSysFileMap(Map<String, String> map) {synchronized (mLock) {final int size = mCoreAndFrequencies.size();for (int i = 0; i < size; i++) {final int core = mCoreAndFrequencies.keyAt(i);final long freq = mCoreAndFrequencies.valueAt(i);final String file = "/sys/devices/system/cpu/cpu" + Integer.toString(core) +"/cpufreq/scaling_max_freq";map.put(file, Long.toString(freq));}}}
}