1 /* 2 * Copyright (C) 2015 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 package com.android.internal.os; 17 18 import android.annotation.Nullable; 19 import android.os.SystemClock; 20 import android.text.TextUtils; 21 import android.util.Slog; 22 import android.util.SparseLongArray; 23 import android.util.TimeUtils; 24 25 import java.io.BufferedReader; 26 import java.io.FileReader; 27 import java.io.FileWriter; 28 import java.io.IOException; 29 30 /** 31 * Reads /proc/uid_cputime/show_uid_stat which has the line format: 32 * 33 * uid: user_time_micro_seconds system_time_micro_seconds power_in_milli-amp-micro_seconds 34 * 35 * This provides the time a UID's processes spent executing in user-space and kernel-space. 36 * The file contains a monotonically increasing count of time for a single boot. This class 37 * maintains the previous results of a call to {@link #readDelta} in order to provide a proper 38 * delta. 39 */ 40 public class KernelUidCpuTimeReader { 41 private static final String TAG = "KernelUidCpuTimeReader"; 42 private static final String sProcFile = "/proc/uid_cputime/show_uid_stat"; 43 private static final String sRemoveUidProcFile = "/proc/uid_cputime/remove_uid_range"; 44 45 /** 46 * Callback interface for processing each line of the proc file. 47 */ 48 public interface Callback { 49 /** 50 * @param uid UID of the app 51 * @param userTimeUs time spent executing in user space in microseconds 52 * @param systemTimeUs time spent executing in kernel space in microseconds 53 * @param powerMaUs power consumed executing, in milli-ampere microseconds 54 */ 55 void onUidCpuTime(int uid, long userTimeUs, long systemTimeUs, long powerMaUs); 56 } 57 58 private SparseLongArray mLastUserTimeUs = new SparseLongArray(); 59 private SparseLongArray mLastSystemTimeUs = new SparseLongArray(); 60 private SparseLongArray mLastPowerMaUs = new SparseLongArray(); 61 private long mLastTimeReadUs = 0; 62 63 /** 64 * Reads the proc file, calling into the callback with a delta of time for each UID. 65 * @param callback The callback to invoke for each line of the proc file. If null, 66 * the data is consumed and subsequent calls to readDelta will provide 67 * a fresh delta. 68 */ 69 public void readDelta(@Nullable Callback callback) { 70 long nowUs = SystemClock.elapsedRealtime() * 1000; 71 try (BufferedReader reader = new BufferedReader(new FileReader(sProcFile))) { 72 TextUtils.SimpleStringSplitter splitter = new TextUtils.SimpleStringSplitter(' '); 73 String line; 74 while ((line = reader.readLine()) != null) { 75 splitter.setString(line); 76 final String uidStr = splitter.next(); 77 final int uid = Integer.parseInt(uidStr.substring(0, uidStr.length() - 1), 10); 78 final long userTimeUs = Long.parseLong(splitter.next(), 10); 79 final long systemTimeUs = Long.parseLong(splitter.next(), 10); 80 final long powerMaUs; 81 if (splitter.hasNext()) { 82 powerMaUs = Long.parseLong(splitter.next(), 10) / 1000; 83 } else { 84 powerMaUs = 0; 85 } 86 87 // Only report if there is a callback and if this is not the first read. 88 if (callback != null && mLastTimeReadUs != 0) { 89 long userTimeDeltaUs = userTimeUs; 90 long systemTimeDeltaUs = systemTimeUs; 91 long powerDeltaMaUs = powerMaUs; 92 int index = mLastUserTimeUs.indexOfKey(uid); 93 if (index >= 0) { 94 userTimeDeltaUs -= mLastUserTimeUs.valueAt(index); 95 systemTimeDeltaUs -= mLastSystemTimeUs.valueAt(index); 96 powerDeltaMaUs -= mLastPowerMaUs.valueAt(index); 97 98 final long timeDiffUs = nowUs - mLastTimeReadUs; 99 if (userTimeDeltaUs < 0 || systemTimeDeltaUs < 0 || powerDeltaMaUs < 0) { 100 StringBuilder sb = new StringBuilder("Malformed cpu data for UID="); 101 sb.append(uid).append("!\n"); 102 sb.append("Time between reads: "); 103 TimeUtils.formatDuration(timeDiffUs / 1000, sb); 104 sb.append("\n"); 105 sb.append("Previous times: u="); 106 TimeUtils.formatDuration(mLastUserTimeUs.valueAt(index) / 1000, sb); 107 sb.append(" s="); 108 TimeUtils.formatDuration(mLastSystemTimeUs.valueAt(index) / 1000, sb); 109 sb.append(" p=").append(mLastPowerMaUs.valueAt(index) / 1000); 110 sb.append("mAms\n"); 111 112 sb.append("Current times: u="); 113 TimeUtils.formatDuration(userTimeUs / 1000, sb); 114 sb.append(" s="); 115 TimeUtils.formatDuration(systemTimeUs / 1000, sb); 116 sb.append(" p=").append(powerMaUs / 1000); 117 sb.append("mAms\n"); 118 sb.append("Delta: u="); 119 TimeUtils.formatDuration(userTimeDeltaUs / 1000, sb); 120 sb.append(" s="); 121 TimeUtils.formatDuration(systemTimeDeltaUs / 1000, sb); 122 sb.append(" p=").append(powerDeltaMaUs / 1000).append("mAms"); 123 Slog.e(TAG, sb.toString()); 124 125 userTimeDeltaUs = 0; 126 systemTimeDeltaUs = 0; 127 powerDeltaMaUs = 0; 128 } 129 } 130 131 if (userTimeDeltaUs != 0 || systemTimeDeltaUs != 0 || powerDeltaMaUs != 0) { 132 callback.onUidCpuTime(uid, userTimeDeltaUs, systemTimeDeltaUs, 133 powerDeltaMaUs); 134 } 135 } 136 mLastUserTimeUs.put(uid, userTimeUs); 137 mLastSystemTimeUs.put(uid, systemTimeUs); 138 mLastPowerMaUs.put(uid, powerMaUs); 139 } 140 } catch (IOException e) { 141 Slog.e(TAG, "Failed to read uid_cputime: " + e.getMessage()); 142 } 143 mLastTimeReadUs = nowUs; 144 } 145 146 /** 147 * Removes the UID from the kernel module and from internal accounting data. 148 * @param uid The UID to remove. 149 */ 150 public void removeUid(int uid) { 151 int index = mLastUserTimeUs.indexOfKey(uid); 152 if (index >= 0) { 153 mLastUserTimeUs.removeAt(index); 154 mLastSystemTimeUs.removeAt(index); 155 mLastPowerMaUs.removeAt(index); 156 } 157 158 try (FileWriter writer = new FileWriter(sRemoveUidProcFile)) { 159 writer.write(Integer.toString(uid) + "-" + Integer.toString(uid)); 160 writer.flush(); 161 } catch (IOException e) { 162 Slog.e(TAG, "failed to remove uid from uid_cputime module", e); 163 } 164 } 165 } 166
