Add a dual clock profiler tracing mode.

Dalvik previously supported using either the thread-cpu clock
or the real time clock as the timebase for profiler traces.
This change adds a dual clock mode where both thread-cpu time
and real time timestamps are collected.

Using dual clock mode significantly improves TraceView ability
to accurately reconstruct the global timeline of events,
particularly on SMP systems.

For now, thread-cpu mode remains the default.

Dual clock mode can be enabled by running the following command
and restarting the system server.
   adb shell setprop dalvik.vm.extra-opts -Xprofile:dualclock

Change-Id: I8c0d91a99aa6829dadea328e54dc1225d9827391

1 files changed, 34 insertions, 12 deletions

diff --git a/tools/dmtracedump/TraceDump.c b/tools/dmtracedump/TraceDump.c
index b60bbf5a9..976fe5f0e 100644
--- a/tools/dmtracedump/TraceDump.c
+++ b/tools/dmtracedump/TraceDump.c
@@ -32,8 +32,10 @@
 #include <errno.h>
 #include <assert.h>
 
-/* Version number in the key file.  Version 1 uses one byte for the thread id.
+/* Version number in the key file.
+ * Version 1 uses one byte for the thread id.
  * Version 2 uses two bytes for the thread ids.
+ * Version 3 encodes the record size and adds an optional extra timestamp field.
  */
 int versionNumber;
 
@@ -119,6 +121,7 @@ typedef struct DataHeader {
     short version;
     short offsetToData;
     long long startWhen;
+    short recordSize;
 } DataHeader;
 
 /*
@@ -1065,12 +1068,26 @@ unsigned long long read8LE(FILE* fp)
  */
 int parseDataHeader(FILE *fp, DataHeader* pHeader)
 {
+    int bytesToRead;
+
     pHeader->magic = read4LE(fp);
     pHeader->version = read2LE(fp);
     pHeader->offsetToData = read2LE(fp);
     pHeader->startWhen = read8LE(fp);
+    bytesToRead = pHeader->offsetToData - 16;
+    if (pHeader->version == 1) {
+        pHeader->recordSize = 9;
+    } else if (pHeader->version == 2) {
+        pHeader->recordSize = 10;
+    } else if (pHeader->version == 3) {
+        pHeader->recordSize = read2LE(fp);
+        bytesToRead -= 2;
+    } else {
+        fprintf(stderr, "Unsupported trace file version: %d\n", pHeader->version);
+        return -1;
+    }
 
-    if (fseek(fp, pHeader->offsetToData - 16, SEEK_CUR) != 0) {
+    if (fseek(fp, bytesToRead, SEEK_CUR) != 0) {
         return -1;
     }
 
@@ -1111,20 +1128,19 @@ MethodEntry* lookupMethod(DataKeys* pKeys, unsigned int methodId)
  * and elapsedTime are unchanged.  Returns 1 on end-of-file, otherwise
  * returns 0.
  */
-int readDataRecord(FILE *dataFp, int *threadId, unsigned int *methodVal,
-                   uint64_t *elapsedTime)
+int readDataRecord(FILE *dataFp, DataHeader* dataHeader,
+        int *threadId, unsigned int *methodVal, uint64_t *elapsedTime)
 {
     int id;
+    int bytesToRead;
 
-    /*
-     * TODO:
-     * This SHOULD NOT be keyed off of the global version number!  Use
-     * a name=value setting in the version area instead!
-     */
-    if (versionNumber == 1) {
+    bytesToRead = dataHeader->recordSize;
+    if (dataHeader->version == 1) {
         id = getc(dataFp);
+        bytesToRead -= 1;
     } else {
         id = read2LE(dataFp);
+        bytesToRead -= 2;
     }
     if (id == EOF)
         return 1;
@@ -1132,6 +1148,12 @@ int readDataRecord(FILE *dataFp, int *threadId, unsigned int *methodVal,
 
     *methodVal = read4LE(dataFp);
     *elapsedTime = read4LE(dataFp);
+    bytesToRead -= 8;
+
+    while (bytesToRead-- > 0) {
+        getc(dataFp);
+    }
+
     if (feof(dataFp)) {
         fprintf(stderr, "WARNING: hit EOF mid-record\n");
         return 1;
@@ -1189,7 +1211,7 @@ void dumpTrace()
         /*
          * Extract values from file.
          */
-        if (readDataRecord(dataFp, &threadId, &methodVal, &elapsedTime))
+        if (readDataRecord(dataFp, &dataHeader, &threadId, &methodVal, &elapsedTime))
             break;
 
         action = METHOD_ACTION(methodVal);
@@ -2301,7 +2323,7 @@ DataKeys* parseDataKeys(TraceData* traceData, const char* traceFileName, uint64_
         /*
          * Extract values from file.
          */
-        if (readDataRecord(dataFp, &threadId, &methodVal, &currentTime))
+        if (readDataRecord(dataFp, &dataHeader, &threadId, &methodVal, &currentTime))
             break;
 
         action = METHOD_ACTION(methodVal);