Merge "Don\'t assume kernel tick is 100Hz" into mnc-dr1.5-dev am: 0064c4c793 am: e8b476e8e8
am: afbf1570ac
* commit 'afbf1570acfac5dfc28196c3f4b424fdaef85508':
Don't assume kernel tick is 100Hz
diff --git a/core/java/com/android/internal/os/KernelCpuSpeedReader.java b/core/java/com/android/internal/os/KernelCpuSpeedReader.java
index 5b776ac..3f6ebb9 100644
--- a/core/java/com/android/internal/os/KernelCpuSpeedReader.java
+++ b/core/java/com/android/internal/os/KernelCpuSpeedReader.java
@@ -16,8 +16,11 @@
package com.android.internal.os;
import android.text.TextUtils;
+import android.system.OsConstants;
import android.util.Slog;
+import libcore.io.Libcore;
+
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
@@ -29,7 +32,7 @@
*
* freq time
*
- * where time is measured in 1/100 seconds.
+ * where time is measured in jiffies.
*/
public class KernelCpuSpeedReader {
private static final String TAG = "KernelCpuSpeedReader";
@@ -38,6 +41,9 @@
private final long[] mLastSpeedTimes;
private final long[] mDeltaSpeedTimes;
+ // How long a CPU jiffy is in milliseconds.
+ private final long mJiffyMillis;
+
/**
* @param cpuNumber The cpu (cpu0, cpu1, etc) whose state to read.
*/
@@ -46,6 +52,8 @@
cpuNumber);
mLastSpeedTimes = new long[numSpeedSteps];
mDeltaSpeedTimes = new long[numSpeedSteps];
+ long jiffyHz = Libcore.os.sysconf(OsConstants._SC_CLK_TCK);
+ mJiffyMillis = 1000/jiffyHz;
}
/**
@@ -62,8 +70,7 @@
splitter.setString(line);
Long.parseLong(splitter.next());
- // The proc file reports time in 1/100 sec, so convert to milliseconds.
- long time = Long.parseLong(splitter.next()) * 10;
+ long time = Long.parseLong(splitter.next()) * mJiffyMillis;
if (time < mLastSpeedTimes[speedIndex]) {
// The stats reset when the cpu hotplugged. That means that the time
// we read is offset from 0, so the time is the delta.
diff --git a/core/java/com/android/internal/os/ProcessCpuTracker.java b/core/java/com/android/internal/os/ProcessCpuTracker.java
index bf97f1f..d831902 100644
--- a/core/java/com/android/internal/os/ProcessCpuTracker.java
+++ b/core/java/com/android/internal/os/ProcessCpuTracker.java
@@ -67,10 +67,10 @@
static final int PROCESS_STAT_UTIME = 2;
static final int PROCESS_STAT_STIME = 3;
- /** Stores user time and system time in 100ths of a second. */
+ /** Stores user time and system time in jiffies. */
private final long[] mProcessStatsData = new long[4];
- /** Stores user time and system time in 100ths of a second. Used for
+ /** Stores user time and system time in jiffies. Used for
* public API to retrieve CPU use for a process. Must lock while in use. */
private final long[] mSinglePidStatsData = new long[4];