ProcessStats: Handle changes in the scaling frequnencylinaro_android_4.2.2

Switching from MP to IKS mode results increase in number of operating points
and results in bug #1183781 . The patch makes sure that whenever the available
scaling frequency changes it resets the existing values and sets them as per the
new values.

Change-Id: Ic74cdc2015f3c4ddd61cb116d1f4b4ed1204a3bf
Signed-off-by: Vishal Bhoj <vishal.bhoj@linaro.org>

1 files changed, 31 insertions, 3 deletions

diff --git a/core/java/com/android/internal/os/ProcessStats.java b/core/java/com/android/internal/os/ProcessStats.java
index f295636e3239..b1ea5c897f30 100644
--- a/core/java/com/android/internal/os/ProcessStats.java
+++ b/core/java/com/android/internal/os/ProcessStats.java
@@ -30,6 +30,7 @@ import java.io.StringWriter;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.Date;
 import java.util.StringTokenizer;
 
 public class ProcessStats {
@@ -171,6 +172,11 @@ public class ProcessStats {
      */
     private long[] mCpuSpeeds;
 
+    /**
+     * The lastmodified date of sysfs entry to detect change in available scaling frequency
+     */
+    private Date mLastModified = null;
+
     public static class Stats {
         public final int pid;
         final String statFile;
@@ -557,9 +563,25 @@ public class ProcessStats {
         long[] tempTimes = out;
         long[] tempSpeeds = mCpuSpeeds;
         final int MAX_SPEEDS = 60;
-        if (out == null || out.length == 0) {
+        Date currentModified = null;
+
+        try {
+            File file = new File("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies");
+            if (file.exists()) {
+                currentModified = new Date(file.lastModified());
+            }
+        } catch (Exception e) {
+            Slog.i(TAG, "Exception = " + e);
+            }
+        if (mLastModified == null) {
+            mLastModified = currentModified;
+        }
+        if (out == null || out.length == 0 || mLastModified != currentModified) {
             tempTimes = new long[MAX_SPEEDS]; // Hopefully no more than that
             tempSpeeds = new long[MAX_SPEEDS];
+            mLastModified = currentModified;
+            // We need to clean up previous scaling frequency since they need to be updated
+            out = null;
         }
         int speed = 0;
         String file = readFile("/sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state", '\0');
@@ -580,8 +602,14 @@ public class ProcessStats {
                         Slog.v(TAG, "First time : Speed/Time = " + tempSpeeds[speed - 1]
                               + "\t" + tempTimes[speed - 1]);
                     }
-                } catch (NumberFormatException nfe) {
-                    Slog.i(TAG, "Unable to parse time_in_state");
+               } catch (Exception e) {
+                    if (e instanceof NumberFormatException) {
+                        Slog.i(TAG, "Unable to parse time_in_state");
+                    }
+                    else if (e instanceof ArrayIndexOutOfBoundsException) {
+                        Slog.i(TAG, "Scaling frequency changed while accessing" +
+                            " the time_in_state, It will be handled when the function is called again");
+                    }
                 }
             }
         }