diff -r 000000000000 -r 6474c204b198 tools/profiler/merge-profiles.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/profiler/merge-profiles.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,88 @@
+#!/usr/bin/env python 
+#
+# This script takes b2g process profiles and merged them into a single profile.
+# The meta data is taken from the first profile. The startTime for each profile
+# is used to syncronized the samples. Each thread is moved into the merged
+# profile.
+#
+import json
+import re
+import sys
+
+def MergeProfiles(files):
+    threads = []
+    fileData = []
+    symTable = dict()
+    meta = None
+    libs = None
+    minStartTime = None
+
+    for fname in files:
+        match = re.match('profile_([0-9]+)_(.+)\.sym', fname)
+        if match is None:
+            raise Exception("Filename '" + fname + "' doesn't match expected pattern")
+        pid = match.groups(0)[0]
+        pname = match.groups(0)[1]
+
+        fp = open(fname, "r")
+        fileData = json.load(fp)
+        fp.close()
+
+        if meta is None:
+            meta = fileData['profileJSON']['meta'].copy()
+            libs = fileData['profileJSON']['libs']
+            minStartTime = meta['startTime']
+        else:
+            minStartTime = min(minStartTime, fileData['profileJSON']['meta']['startTime'])
+            meta['startTime'] = minStartTime
+
+        for thread in fileData['profileJSON']['threads']:
+            thread['name'] = thread['name'] + " (" + pname + ":" + pid + ")"
+            threads.append(thread)
+
+            # Note that pid + sym, pid + location could be ambigious
+            # if we had pid=11 sym=1 && pid=1 sym=11.
+            pidStr = pid + ":"
+
+            thread['startTime'] = fileData['profileJSON']['meta']['startTime']
+            samples = thread['samples']
+            for sample in thread['samples']:
+                for frame in sample['frames']:
+                    if "location" in frame and frame['location'][0:2] == '0x':
+                        oldLoc = frame['location']
+                        newLoc = pidStr + oldLoc
+                        frame['location'] = newLoc
+                        # Default to the unprefixed symbol if no translation is available
+                        symTable[newLoc] = oldLoc
+
+        filesyms = fileData['symbolicationTable']
+        for sym in filesyms.keys():
+            symTable[pidStr + sym] = filesyms[sym]
+
+    # For each thread, make the time offsets line up based on the
+    # earliest start
+    for thread in threads:
+        delta = thread['startTime'] - minStartTime
+        for sample in thread['samples']:
+            if "time" in sample:
+                sample['time'] += delta
+
+    result = dict()
+    result['profileJSON'] = dict()
+    result['profileJSON']['meta'] = meta
+    result['profileJSON']['libs'] = libs
+    result['profileJSON']['threads'] = threads
+    result['symbolicationTable'] = symTable
+    result['format'] = "profileJSONWithSymbolicationTable,1"
+
+    json.dump(result, sys.stdout)
+
+
+if len(sys.argv) > 1:
+    MergeProfiles(sys.argv[1:])
+    sys.exit(0)
+
+print "Usage: merge-profile.py profile_<pid1>_<pname1>.sym profile_<pid2>_<pname2>.sym > merged.sym"
+
+
+