From 469a194051f1657b3f77ff2f5d84a60f7521faba Mon Sep 17 00:00:00 2001
From: John Reck <jreck@google.com>
Date: Thu, 26 Mar 2015 15:31:35 -0700
Subject: [PATCH] Add trace_event_clock_sync to atrace

Change-Id: I8adce15210d82df09ff3a39ddd8df617aeb16a42
---
 cmds/atrace/atrace.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/cmds/atrace/atrace.cpp b/cmds/atrace/atrace.cpp
index 8fd80cc02..515d761f4 100644
--- a/cmds/atrace/atrace.cpp
+++ b/cmds/atrace/atrace.cpp
@@ -35,6 +35,7 @@
 #include <cutils/properties.h>
 
 #include <utils/String8.h>
+#include <utils/Timers.h>
 #include <utils/Trace.h>
 
 using namespace android;
@@ -192,6 +193,9 @@ static const char* k_tracingOnPath =
 static const char* k_tracePath =
     "/sys/kernel/debug/tracing/trace";
 
+static const char* k_traceMarkerPath =
+    "/sys/kernel/debug/tracing/trace_marker";
+
 // Check whether a file exists.
 static bool fileExists(const char* filename) {
     return access(filename, F_OK) != -1;
@@ -254,6 +258,14 @@ static bool appendStr(const char* filename, const char* str)
     return _writeStr(filename, str, O_APPEND|O_WRONLY);
 }
 
+static void writeClockSyncMarker()
+{
+  char buffer[128];
+  float now_in_seconds = systemTime(CLOCK_MONOTONIC) / 1000000000.0f;
+  snprintf(buffer, 128, "trace_event_clock_sync: parent_ts=%f\n", now_in_seconds);
+  writeStr(k_traceMarkerPath, buffer);
+}
+
 // Enable or disable a kernel option by writing a "1" or a "0" into a /sys
 // file.
 static bool setKernelOptionEnable(const char* filename, bool enable)
@@ -631,6 +643,7 @@ static bool startTrace()
 // Disable tracing in the kernel.
 static void stopTrace()
 {
+    writeClockSyncMarker();
     setTracingEnabled(false);
 }