diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index 1310b83..9d6aef6 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -922,6 +922,7 @@
         int samplingInterval;
         boolean autoStopProfiler;
         boolean streamingOutput;
+        int mClockType;
         boolean profiling;
         boolean handlingProfiling;
         public void setProfiler(ProfilerInfo profilerInfo) {
@@ -948,6 +949,7 @@
             samplingInterval = profilerInfo.samplingInterval;
             autoStopProfiler = profilerInfo.autoStopProfiler;
             streamingOutput = profilerInfo.streamingOutput;
+            mClockType = profilerInfo.clockType;
         }
         public void startProfiling() {
             if (profileFd == null || profiling) {
@@ -956,8 +958,8 @@
             try {
                 int bufferSize = SystemProperties.getInt("debug.traceview-buffer-size-mb", 8);
                 VMDebug.startMethodTracing(profileFile, profileFd.getFileDescriptor(),
-                        bufferSize * 1024 * 1024, 0, samplingInterval != 0, samplingInterval,
-                        streamingOutput);
+                        bufferSize * 1024 * 1024, mClockType, samplingInterval != 0,
+                        samplingInterval, streamingOutput);
                 profiling = true;
             } catch (RuntimeException e) {
                 Slog.w(TAG, "Profiling failed on path " + profileFile, e);
@@ -6479,6 +6481,7 @@
             mProfiler.samplingInterval = data.initProfilerInfo.samplingInterval;
             mProfiler.autoStopProfiler = data.initProfilerInfo.autoStopProfiler;
             mProfiler.streamingOutput = data.initProfilerInfo.streamingOutput;
+            mProfiler.mClockType = data.initProfilerInfo.clockType;
             if (data.initProfilerInfo.attachAgentDuringBind) {
                 agent = data.initProfilerInfo.agent;
             }
diff --git a/core/java/android/app/ProfilerInfo.java b/core/java/android/app/ProfilerInfo.java
index 854406c..f7a3d78 100644
--- a/core/java/android/app/ProfilerInfo.java
+++ b/core/java/android/app/ProfilerInfo.java
@@ -33,6 +33,17 @@
  */
 public class ProfilerInfo implements Parcelable {
 
+    // CLOCK_TYPE_DEFAULT chooses the default used by ART. ART uses CLOCK_TYPE_DUAL by default (see
+    // kDefaultTraceClockSource in art/runtime/runtime_globals.h).
+    public static final int CLOCK_TYPE_DEFAULT = 0x000;
+    // The values of these constants are chosen such that they correspond to the flags passed to
+    // VMDebug.startMethodTracing to choose the corresponding clock type (see
+    // core/java/android/app/ActivityThread.java).
+    // The flag values are defined in ART (see TraceFlag in art/runtime/trace.h).
+    public static final int CLOCK_TYPE_WALL = 0x010;
+    public static final int CLOCK_TYPE_THREAD_CPU = 0x100;
+    public static final int CLOCK_TYPE_DUAL = 0x110;
+
     private static final String TAG = "ProfilerInfo";
 
     /* Name of profile output file. */
@@ -66,13 +77,20 @@
      */
     public final boolean attachAgentDuringBind;
 
+    /**
+     * Indicates the clock source to be used for profiling. The source could be wallclock, thread
+     * cpu or both
+     */
+    public final int clockType;
+
     public ProfilerInfo(String filename, ParcelFileDescriptor fd, int interval, boolean autoStop,
-            boolean streaming, String agent, boolean attachAgentDuringBind) {
+            boolean streaming, String agent, boolean attachAgentDuringBind, int clockType) {
         profileFile = filename;
         profileFd = fd;
         samplingInterval = interval;
         autoStopProfiler = autoStop;
         streamingOutput = streaming;
+        this.clockType = clockType;
         this.agent = agent;
         this.attachAgentDuringBind = attachAgentDuringBind;
     }
@@ -85,6 +103,25 @@
         streamingOutput = in.streamingOutput;
         agent = in.agent;
         attachAgentDuringBind = in.attachAgentDuringBind;
+        clockType = in.clockType;
+    }
+
+    /**
+     * Get the value for the clock type corresponding to the option string passed to the activity
+     * manager. am profile start / am start-activity start-profiler commands accept clock-type
+     * option to choose the source of timestamps when profiling. This function maps the option
+     * string to the value of flags that is used when calling VMDebug.startMethodTracing
+     */
+    public static int getClockTypeFromString(String type) {
+        if ("thread-cpu".equals(type)) {
+            return CLOCK_TYPE_THREAD_CPU;
+        } else if ("wall".equals(type)) {
+            return CLOCK_TYPE_WALL;
+        } else if ("dual".equals(type)) {
+            return CLOCK_TYPE_DUAL;
+        } else {
+            return CLOCK_TYPE_DEFAULT;
+        }
     }
 
     /**
@@ -93,7 +130,8 @@
      */
     public ProfilerInfo setAgent(String agent, boolean attachAgentDuringBind) {
         return new ProfilerInfo(this.profileFile, this.profileFd, this.samplingInterval,
-                this.autoStopProfiler, this.streamingOutput, agent, attachAgentDuringBind);
+                this.autoStopProfiler, this.streamingOutput, agent, attachAgentDuringBind,
+                this.clockType);
     }
 
     /**
@@ -133,6 +171,7 @@
         out.writeInt(streamingOutput ? 1 : 0);
         out.writeString(agent);
         out.writeBoolean(attachAgentDuringBind);
+        out.writeInt(clockType);
     }
 
     /** @hide */
@@ -146,6 +185,7 @@
         proto.write(ProfilerInfoProto.AUTO_STOP_PROFILER, autoStopProfiler);
         proto.write(ProfilerInfoProto.STREAMING_OUTPUT, streamingOutput);
         proto.write(ProfilerInfoProto.AGENT, agent);
+        proto.write(ProfilerInfoProto.CLOCK_TYPE, clockType);
         proto.end(token);
     }
 
@@ -170,6 +210,7 @@
         streamingOutput = in.readInt() != 0;
         agent = in.readString();
         attachAgentDuringBind = in.readBoolean();
+        clockType = in.readInt();
     }
 
     @Override
@@ -186,7 +227,8 @@
                 && autoStopProfiler == other.autoStopProfiler
                 && samplingInterval == other.samplingInterval
                 && streamingOutput == other.streamingOutput
-                && Objects.equals(agent, other.agent);
+                && Objects.equals(agent, other.agent)
+                && clockType == other.clockType;
     }
 
     @Override
@@ -197,6 +239,7 @@
         result = 31 * result + (autoStopProfiler ? 1 : 0);
         result = 31 * result + (streamingOutput ? 1 : 0);
         result = 31 * result + Objects.hashCode(agent);
+        result = 31 * result + clockType;
         return result;
     }
 }
diff --git a/core/proto/android/app/profilerinfo.proto b/core/proto/android/app/profilerinfo.proto
index d318533..86261ec 100644
--- a/core/proto/android/app/profilerinfo.proto
+++ b/core/proto/android/app/profilerinfo.proto
@@ -35,4 +35,5 @@
     optional bool streaming_output = 5;
     // Denotes an agent (and its parameters) to attach for profiling.
     optional string agent = 6;
+    optional int32 clock_type = 7;
 }
diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index 869c6a4..625ae58 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -90,7 +90,6 @@
 import android.os.ShellCommand;
 import android.os.StrictMode;
 import android.os.SystemClock;
-import android.os.SystemProperties;
 import android.os.Trace;
 import android.os.UserHandle;
 import android.os.UserManager;
@@ -175,6 +174,7 @@
     private boolean mStreaming;   // Streaming the profiling output to a file.
     private String mAgent;  // Agent to attach on startup.
     private boolean mAttachAgentDuringBind;  // Whether agent should be attached late.
+    private int mClockType; // Whether we need thread cpu / wall clock / both.
     private int mDisplayId;
     private int mTaskDisplayAreaFeatureId;
     private int mWindowingMode;
@@ -398,6 +398,9 @@
                     mAutoStop = false;
                 } else if (opt.equals("--sampling")) {
                     mSamplingInterval = Integer.parseInt(getNextArgRequired());
+                } else if (opt.equals("--clock-type")) {
+                    String clock_type = getNextArgRequired();
+                    mClockType = ProfilerInfo.getClockTypeFromString(clock_type);
                 } else if (opt.equals("--streaming")) {
                     mStreaming = true;
                 } else if (opt.equals("--attach-agent")) {
@@ -546,7 +549,7 @@
                     }
                 }
                 profilerInfo = new ProfilerInfo(mProfileFile, fd, mSamplingInterval, mAutoStop,
-                        mStreaming, mAgent, mAttachAgentDuringBind);
+                        mStreaming, mAgent, mAttachAgentDuringBind, mClockType);
             }
 
             pw.println("Starting: " + intent);
@@ -876,24 +879,15 @@
         return 0;
     }
 
-    static void removeWallOption() {
-        String props = SystemProperties.get("dalvik.vm.extra-opts");
-        if (props != null && props.contains("-Xprofile:wallclock")) {
-            props = props.replace("-Xprofile:wallclock", "");
-            props = props.trim();
-            SystemProperties.set("dalvik.vm.extra-opts", props);
-        }
-    }
-
     private int runProfile(PrintWriter pw) throws RemoteException {
         final PrintWriter err = getErrPrintWriter();
         String profileFile = null;
         boolean start = false;
-        boolean wall = false;
         int userId = UserHandle.USER_CURRENT;
         int profileType = 0;
         mSamplingInterval = 0;
         mStreaming = false;
+        mClockType = ProfilerInfo.CLOCK_TYPE_DEFAULT;
 
         String process = null;
 
@@ -905,8 +899,9 @@
             while ((opt=getNextOption()) != null) {
                 if (opt.equals("--user")) {
                     userId = UserHandle.parseUserArg(getNextArgRequired());
-                } else if (opt.equals("--wall")) {
-                    wall = true;
+                } else if (opt.equals("--clock-type")) {
+                    String clock_type = getNextArgRequired();
+                    mClockType = ProfilerInfo.getClockTypeFromString(clock_type);
                 } else if (opt.equals("--streaming")) {
                     mStreaming = true;
                 } else if (opt.equals("--sampling")) {
@@ -954,29 +949,12 @@
                 return -1;
             }
             profilerInfo = new ProfilerInfo(profileFile, fd, mSamplingInterval, false, mStreaming,
-                    null, false);
+                    null, false, mClockType);
         }
 
-        try {
-            if (wall) {
-                // XXX doesn't work -- this needs to be set before booting.
-                String props = SystemProperties.get("dalvik.vm.extra-opts");
-                if (props == null || !props.contains("-Xprofile:wallclock")) {
-                    props = props + " -Xprofile:wallclock";
-                    //SystemProperties.set("dalvik.vm.extra-opts", props);
-                }
-            } else if (start) {
-                //removeWallOption();
-            }
-            if (!mInterface.profileControl(process, userId, start, profilerInfo, profileType)) {
-                wall = false;
-                err.println("PROFILE FAILED on process " + process);
-                return -1;
-            }
-        } finally {
-            if (!wall) {
-                //removeWallOption();
-            }
+        if (!mInterface.profileControl(process, userId, start, profilerInfo, profileType)) {
+            err.println("PROFILE FAILED on process " + process);
+            return -1;
         }
         return 0;
     }
@@ -3449,8 +3427,9 @@
             pw.println("  help");
             pw.println("      Print this help text.");
             pw.println("  start-activity [-D] [-N] [-W] [-P <FILE>] [--start-profiler <FILE>]");
-            pw.println("          [--sampling INTERVAL] [--streaming] [-R COUNT] [-S]");
-            pw.println("          [--track-allocation] [--user <USER_ID> | current] <INTENT>");
+            pw.println("          [--sampling INTERVAL] [--clock-type <TYPE>] [--streaming]");
+            pw.println("          [-R COUNT] [-S] [--track-allocation]");
+            pw.println("          [--user <USER_ID> | current] <INTENT>");
             pw.println("      Start an Activity.  Options are:");
             pw.println("      -D: enable debugging");
             pw.println("      -N: enable native debugging");
@@ -3458,6 +3437,9 @@
             pw.println("      --start-profiler <FILE>: start profiler and send results to <FILE>");
             pw.println("      --sampling INTERVAL: use sample profiling with INTERVAL microseconds");
             pw.println("          between samples (use with --start-profiler)");
+            pw.println("      --clock-type <TYPE>: type can be wall / thread-cpu / dual. Specify");
+            pw.println("          the clock that is used to report the timestamps when profiling");
+            pw.println("          The default value is dual. (use with --start-profiler)");
             pw.println("      --streaming: stream the profiling output to the specified file");
             pw.println("          (use with --start-profiler)");
             pw.println("      -P <FILE>: like above, but profiling stops when app goes idle");
@@ -3535,12 +3517,16 @@
             pw.println("      stop: stop tracing IPC transactions and dump the results to file.");
             pw.println("      --dump-file <FILE>: Specify the file the trace should be dumped to.");
             pw.println("  profile start [--user <USER_ID> current]");
+            pw.println("          [--clock-type <TYPE>]");
             pw.println("          [--sampling INTERVAL | --streaming] <PROCESS> <FILE>");
             pw.println("      Start profiler on a process.  The given <PROCESS> argument");
             pw.println("        may be either a process name or pid.  Options are:");
             pw.println("      --user <USER_ID> | current: When supplying a process name,");
             pw.println("          specify user of process to profile; uses current user if not");
             pw.println("          specified.");
+            pw.println("      --clock-type <TYPE>: use the specified clock to report timestamps.");
+            pw.println("          The type can be one of wall | thread-cpu | dual. The default");
+            pw.println("          value is dual.");
             pw.println("      --sampling INTERVAL: use sample profiling with INTERVAL microseconds");
             pw.println("          between samples.");
             pw.println("      --streaming: stream the profiling output to the specified file.");
diff --git a/services/core/java/com/android/server/am/AppProfiler.java b/services/core/java/com/android/server/am/AppProfiler.java
index e97654c..15efb7d 100644
--- a/services/core/java/com/android/server/am/AppProfiler.java
+++ b/services/core/java/com/android/server/am/AppProfiler.java
@@ -2043,7 +2043,7 @@
                 }
             } else if (instr != null && instr.mProfileFile != null) {
                 profilerInfo = new ProfilerInfo(instr.mProfileFile, null, 0, false, false,
-                        null, false);
+                        null, false, 0);
             }
             if (mAppAgentMap != null && mAppAgentMap.containsKey(processName)) {
                 // We need to do a debuggable check here. See setAgentApp for why the check is
@@ -2053,7 +2053,7 @@
                     // Do not overwrite already requested agent.
                     if (profilerInfo == null) {
                         profilerInfo = new ProfilerInfo(null, null, 0, false, false,
-                                mAppAgentMap.get(processName), true);
+                                mAppAgentMap.get(processName), true, 0);
                     } else if (profilerInfo.agent == null) {
                         profilerInfo = profilerInfo.setAgent(mAppAgentMap.get(processName), true);
                     }
@@ -2185,7 +2185,9 @@
                             + " mAutoStopProfiler="
                             + mProfileData.getProfilerInfo().autoStopProfiler
                             + " mStreamingOutput="
-                            + mProfileData.getProfilerInfo().streamingOutput);
+                            + mProfileData.getProfilerInfo().streamingOutput
+                            + " mClockType="
+                            + mProfileData.getProfilerInfo().clockType);
                     pw.println("  mProfileType=" + mProfileType);
                 }
             }