diff --git a/src/log.py b/src/log.py
index 4f50046741320c1d79b9f82b0f352cd4c151d634..f0639895fd4fe9630d3c9aa7699f7f5794d137ce 100644
--- a/src/log.py
+++ b/src/log.py
@@ -96,14 +96,16 @@ class LogManager:
                 raise IOError, "cowardly refusing to overwrite '%s'" % self.filename
 
         from time import time
-        self.last_checkpoint = time()
+        self.start_time = time()
 
         self.mpi_comm = mpi_comm
         if mpi_comm is None:
             self.rank = 0
+            self.last_checkpoint = self.start_time
         else:
             self.rank = mpi_comm.rank
-            self.last_sync = self.last_checkpoint
+            self.next_sync = 10
+            self.head_rank = 0
 
         self.t_log = 0
 
@@ -124,15 +126,26 @@ class LogManager:
 
         # synchronize logs with parallel peers, if necessary
         if self.mpi_comm is not None:
-            if end_time - self.last_sync > 10:
-                self.synchronize_logs()
-                self.last_sync = end_time
+            # parallel-case : sync, then checkpoint
+            if self.tick_count == self.next_sync:
 
-        # checkpoint log to disk, if necessary
-        if self.filename is not None:
-            if end_time - self.last_checkpoint > 10:
-                self.save()
-                self.last_checkpoint = end_time
+                if self.filename is not None:
+                    # implicitly synchronizes
+                    self.save()
+                else:
+                    self.synchronize_logs()
+
+                # figure out next sync tick
+                ticks_per_20_sec = 20*self.tick_count/max(1, end_time-self.start_time)
+                self.next_sync = self.tick_count + min(10, ticks_per_20_sec)
+                from boost.mpi import broadcast
+                self.next_sync = broadcast(self.mpi_comm, self.next_sync, self.head_rank)
+        else:
+            # non-parallel-case : checkpoint log to disk, if necessary
+            if self.filename is not None:
+                if end_time - self.last_checkpoint > 10:
+                    self.save()
+                    self.last_checkpoint = end_time
 
     def synchronize_logs(self):
         """Send logs to head node."""
@@ -140,16 +153,20 @@ class LogManager:
             return
 
         from boost.mpi import gather
-        root = 0
-        if self.mpi_comm.rank == root:
-            for rank_data in gather(self.mpi_comm, None, root)[1:]:
+        if self.mpi_comm.rank == self.head_rank:
+            for rank_data in gather(self.mpi_comm, None, self.head_rank)[1:]:
                 for name, rows in rank_data:
-                    self.quantity_data[name].insert_rows(rows)
+                    self.quantity_data[name].table.insert_rows(rows)
         else:
+            # send non-head data away
             gather(self.mpi_comm, 
                     [(name, qdat.table.data)
                         for name, qdat in self.quantity_data.iteritems()], 
-                root)
+                self.head_rank)
+
+            # and erase it
+            for qdat in self.quantity_data.itervalues():
+                qdat.table.clear()
 
     def add_quantity(self, quantity, interval=1):
         """Add an object derived from L{LogQuantity} to this manager."""
@@ -185,6 +202,12 @@ class LogManager:
                 elif agg_name == "avg":
                     from pytools import average
                     agg_func = average
+                elif agg_name == "sum":
+                    agg_func = sum
+                elif agg_name == "norm2":
+                    from math import sqrt
+                    agg_func = lambda iterable: sqrt(
+                            sum(entry**2 for entry in iterable))
                 else:
                     raise ValueError, "invalid rank aggregator '%s'" % agg_name
             elif isinstance(dep, Subscript):
@@ -274,7 +297,7 @@ class LogManager:
 
     def save(self, filename=None):
         self.synchronize_logs()
-        if self.mpi_comm and not self.mpi_comm.rank != 0:
+        if self.mpi_comm and self.mpi_comm.rank != self.head_rank:
             return
 
         if filename is not None:
@@ -300,7 +323,7 @@ class LogManager:
                 open(filename, "w"), protocol=HIGHEST_PROTOCOL)
 
     def load(self, filename):
-        if self.mpi_comm and not self.mpi_comm.rank != 0:
+        if self.mpi_comm and self.mpi_comm.rank != self.head_rank:
             return
 
         from cPickle import load