diff -r b1a59b80e1a3 -r 5a988b3c9645 mercurial/lsprofcalltree.py
--- a/mercurial/lsprofcalltree.py	Sat Jan 02 11:40:53 2016 -0800
+++ b/mercurial/lsprofcalltree.py	Sat Jan 02 11:45:29 2016 -0800
@@ -10,7 +10,7 @@
 of the GNU General Public License, incorporated herein by reference.
 """
 
-from __future__ import absolute_import
+from __future__ import absolute_import, print_function
 
 def label(code):
     if isinstance(code, str):
@@ -27,7 +27,7 @@
 
     def output(self, out_file):
         self.out_file = out_file
-        print >> out_file, 'events: Ticks'
+        print('events: Ticks', file=out_file)
         self._print_summary()
         for entry in self.data:
             self._entry(entry)
@@ -37,24 +37,23 @@
         for entry in self.data:
             totaltime = int(entry.totaltime * 1000)
             max_cost = max(max_cost, totaltime)
-        print >> self.out_file, 'summary: %d' % (max_cost,)
+        print('summary: %d' % max_cost, file=self.out_file)
 
     def _entry(self, entry):
         out_file = self.out_file
 
         code = entry.code
-        #print >> out_file, 'ob=%s' % (code.co_filename,)
         if isinstance(code, str):
-            print >> out_file, 'fi=~'
+            print('fi=~', file=out_file)
         else:
-            print >> out_file, 'fi=%s' % (code.co_filename,)
-        print >> out_file, 'fn=%s' % (label(code),)
+            print('fi=%s' % code.co_filename, file=out_file)
+        print('fn=%s' % label(code), file=out_file)
 
         inlinetime = int(entry.inlinetime * 1000)
         if isinstance(code, str):
-            print >> out_file, '0 ', inlinetime
+            print('0 ', inlinetime, file=out_file)
         else:
-            print >> out_file, '%d %d' % (code.co_firstlineno, inlinetime)
+            print('%d %d' % (code.co_firstlineno, inlinetime), file=out_file)
 
         # recursive calls are counted in entry.calls
         if entry.calls:
@@ -69,20 +68,19 @@
 
         for subentry in calls:
             self._subentry(lineno, subentry)
-        print >> out_file
+        print(file=out_file)
 
     def _subentry(self, lineno, subentry):
         out_file = self.out_file
         code = subentry.code
-        #print >> out_file, 'cob=%s' % (code.co_filename,)
-        print >> out_file, 'cfn=%s' % (label(code),)
+        print('cfn=%s' % label(code), file=out_file)
         if isinstance(code, str):
-            print >> out_file, 'cfi=~'
-            print >> out_file, 'calls=%d 0' % (subentry.callcount,)
+            print('cfi=~', file=out_file)
+            print('calls=%d 0' % subentry.callcount, file=out_file)
         else:
-            print >> out_file, 'cfi=%s' % (code.co_filename,)
-            print >> out_file, 'calls=%d %d' % (
-                subentry.callcount, code.co_firstlineno)
+            print('cfi=%s' % code.co_filename, file=out_file)
+            print('calls=%d %d' % (
+                subentry.callcount, code.co_firstlineno), file=out_file)
 
         totaltime = int(subentry.totaltime * 1000)
-        print >> out_file, '%d %d' % (lineno, totaltime)
+        print('%d %d' % (lineno, totaltime), file=out_file)