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/*
* Copyright (C) 2015 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 com.android.internal.os;
import android.annotation.Nullable;
import android.os.SystemClock;
import android.text.TextUtils;
import android.util.Slog;
import android.util.SparseLongArray;
import android.util.TimeUtils;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
/**
* Reads /proc/uid_cputime/show_uid_stat which has the line format:
*
* uid: user_time_micro_seconds system_time_micro_seconds power_in_milli-amp-micro_seconds
*
* This provides the time a UID's processes spent executing in user-space and kernel-space.
* The file contains a monotonically increasing count of time for a single boot. This class
* maintains the previous results of a call to {@link #readDelta} in order to provide a proper
* delta.
*/
public class KernelUidCpuTimeReader {
private static final String TAG = "KernelUidCpuTimeReader";
private static final String sProcFile = "/proc/uid_cputime/show_uid_stat";
private static final String sRemoveUidProcFile = "/proc/uid_cputime/remove_uid_range";
/**
* Callback interface for processing each line of the proc file.
*/
public interface Callback {
/**
* @param uid UID of the app
* @param userTimeUs time spent executing in user space in microseconds
* @param systemTimeUs time spent executing in kernel space in microseconds
* @param powerMaUs power consumed executing, in milli-ampere microseconds
*/
void onUidCpuTime(int uid, long userTimeUs, long systemTimeUs, long powerMaUs);
}
private SparseLongArray mLastUserTimeUs = new SparseLongArray();
private SparseLongArray mLastSystemTimeUs = new SparseLongArray();
private SparseLongArray mLastPowerMaUs = new SparseLongArray();
private long mLastTimeReadUs = 0;
/**
* Reads the proc file, calling into the callback with a delta of time for each UID.
* @param callback The callback to invoke for each line of the proc file. If null,
* the data is consumed and subsequent calls to readDelta will provide
* a fresh delta.
*/
public void readDelta(@Nullable Callback callback) {
long nowUs = SystemClock.elapsedRealtime() * 1000;
try (BufferedReader reader = new BufferedReader(new FileReader(sProcFile))) {
TextUtils.SimpleStringSplitter splitter = new TextUtils.SimpleStringSplitter(' ');
String line;
while ((line = reader.readLine()) != null) {
splitter.setString(line);
final String uidStr = splitter.next();
final int uid = Integer.parseInt(uidStr.substring(0, uidStr.length() - 1), 10);
final long userTimeUs = Long.parseLong(splitter.next(), 10);
final long systemTimeUs = Long.parseLong(splitter.next(), 10);
final long powerMaUs;
if (splitter.hasNext()) {
powerMaUs = Long.parseLong(splitter.next(), 10) / 1000;
} else {
powerMaUs = 0;
}
if (callback != null) {
long userTimeDeltaUs = userTimeUs;
long systemTimeDeltaUs = systemTimeUs;
long powerDeltaMaUs = powerMaUs;
int index = mLastUserTimeUs.indexOfKey(uid);
if (index >= 0) {
userTimeDeltaUs -= mLastUserTimeUs.valueAt(index);
systemTimeDeltaUs -= mLastSystemTimeUs.valueAt(index);
powerDeltaMaUs -= mLastPowerMaUs.valueAt(index);
final long timeDiffUs = nowUs - mLastTimeReadUs;
if (userTimeDeltaUs < 0 || systemTimeDeltaUs < 0 || powerDeltaMaUs < 0) {
StringBuilder sb = new StringBuilder("Malformed cpu data for UID=");
sb.append(uid).append("!\n");
sb.append("Time between reads: ");
TimeUtils.formatDuration(timeDiffUs / 1000, sb);
sb.append("\n");
sb.append("Previous times: u=");
TimeUtils.formatDuration(mLastUserTimeUs.valueAt(index) / 1000, sb);
sb.append(" s=");
TimeUtils.formatDuration(mLastSystemTimeUs.valueAt(index) / 1000, sb);
sb.append(" p=").append(mLastPowerMaUs.valueAt(index) / 1000);
sb.append("mAms\n");
sb.append("Current times: u=");
TimeUtils.formatDuration(userTimeUs / 1000, sb);
sb.append(" s=");
TimeUtils.formatDuration(systemTimeUs / 1000, sb);
sb.append(" p=").append(powerMaUs / 1000);
sb.append("mAms\n");
sb.append("Delta: u=");
TimeUtils.formatDuration(userTimeDeltaUs / 1000, sb);
sb.append(" s=");
TimeUtils.formatDuration(systemTimeDeltaUs / 1000, sb);
sb.append(" p=").append(powerDeltaMaUs / 1000).append("mAms");
Slog.wtf(TAG, sb.toString());
userTimeDeltaUs = 0;
systemTimeDeltaUs = 0;
powerDeltaMaUs = 0;
}
}
if (userTimeDeltaUs != 0 || systemTimeDeltaUs != 0 || powerDeltaMaUs != 0) {
callback.onUidCpuTime(uid, userTimeDeltaUs, systemTimeDeltaUs,
powerDeltaMaUs);
}
}
mLastUserTimeUs.put(uid, userTimeUs);
mLastSystemTimeUs.put(uid, systemTimeUs);
mLastPowerMaUs.put(uid, powerMaUs);
}
} catch (IOException e) {
Slog.e(TAG, "Failed to read uid_cputime", e);
}
mLastTimeReadUs = nowUs;
}
/**
* Removes the UID from the kernel module and from internal accounting data.
* @param uid The UID to remove.
*/
public void removeUid(int uid) {
int index = mLastUserTimeUs.indexOfKey(uid);
if (index >= 0) {
mLastUserTimeUs.removeAt(index);
mLastSystemTimeUs.removeAt(index);
mLastPowerMaUs.removeAt(index);
}
try (FileWriter writer = new FileWriter(sRemoveUidProcFile)) {
writer.write(Integer.toString(uid) + "-" + Integer.toString(uid));
writer.flush();
} catch (IOException e) {
Slog.e(TAG, "failed to remove uid from uid_cputime module", e);
}
}
}
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