fix error in lpt rebalancing

xtreemfs_client/dataDistribution.py

@@ -190,14 +190,17 @@ class DataDistribution(object):
         return maximum_osd, maximum_processing_time
 
     def get_lower_bound_on_makespan(self):
+        return self.compute_relaxed_assignment().get_maximum_processing_time()[1]
+
+    def compute_relaxed_assignment(self):
         total_remaining_file_size = self.get_total_folder_size()
-        artificial_data_distribution = copy.deepcopy(self)
-        for tmp_osd in artificial_data_distribution.OSDs.values():
+        relaxed_assignment = copy.deepcopy(self)
+        for tmp_osd in relaxed_assignment.OSDs.values():
             for a_folder in list(tmp_osd.folders.keys()):
                 tmp_osd.remove_folder(a_folder)
 
         while total_remaining_file_size > 0:
-            free_OSDs = list(filter(lambda x: x.get_free_capacity() > 0, artificial_data_distribution.OSDs.values()))
+            free_OSDs = list(filter(lambda x: x.get_free_capacity() > 0, relaxed_assignment.OSDs.values()))
             total_bandwidth = sum(list(map(lambda x: x.bandwidth, free_OSDs)))
             assigned_file_size = 0
             for free_OSD in free_OSDs:
@@ -207,7 +210,7 @@ class DataDistribution(object):
                 assigned_file_size += assignable_share
             total_remaining_file_size -= assigned_file_size
 
-        return artificial_data_distribution.get_maximum_processing_time()[1]
+        return relaxed_assignment
 
     def add_folders(self, folders,
                     ignore_osd_capacities=True,
@@ -315,10 +318,12 @@ class DataDistribution(object):
 
         # for each OSD, remove the smallest folder until its total_folder_size does not exceed the reassignment_limit
         # unrolling
+        relaxed_assignment = self.compute_relaxed_assignment()
         for osd in self.OSDs.values():
             # self.get_total_folder_size / self.get_total_bandwidth() is the optimal processing time for each OSD:
             # this value is a lower bound for the makespan
-            reassignment_limit = self.get_rebalance_limit(rebalance_factor, total_folder_size)
+            # reassignment_limit = self.get_rebalance_limit(rebalance_factor, total_folder_size)
+            reassignment_limit = relaxed_assignment.OSDs[osd.uuid].get_processing_time() * rebalance_factor
             while osd.get_processing_time() > reassignment_limit:
                 folder_id, folder_size = osd.get_smallest_folder()
                 folders_to_be_reassigned.append(folder.Folder(folder_id, folder_size, None))