Fix bug in futures implementation and check for pe num in pool examples

charm4py/charm.py

@@ -1158,9 +1158,9 @@ def notify_future_deletion(self, store_id, depth):
             # if yes, remove it
             fut = charm.threadMgr.borrowed_futures[(store_id, depth)]
             refcount = ctypes.c_long.from_address(id(fut)).value
-            #print(store_id, "on pe", charm.myPe(), "depth", depth, "ref count =", refcount)
+            # print(store_id, "on pe", charm.myPe(), "depth", depth, "ref count =", refcount)
             if (fut.parent == None and refcount == 3) or (fut.parent != None and refcount == 2):
-                #print("Real deletion of", store_id, "from", charm.myPe())
+                # print("Real deletion of", store_id, "from", charm.myPe())
                 if fut.parent == None:
                     charm.threadMgr.futures.pop(fut.fid)
                 charm.threadMgr.borrowed_futures.pop((store_id, depth))

charm4py/threads.py

@@ -163,7 +163,13 @@ def __getstate__(self):
         # keep track of how many PEs this future is being sent to
         self.num_borrowers += 1
         if self.store:
-            charm.threadMgr.borrowed_futures[(self.store_id, self.borrow_depth)] = self
+            # print("Getting state for id", self.store_id, "at borrow depth", self.borrow_depth, "num borrowers", self.num_borrowers, "on pe", charm.myPe())
+            #in the case where one pe has 2 instances of futures with matching store ids and borrow depths
+            if (self.store_id, self.borrow_depth) in charm.threadMgr.borrowed_futures:
+                if charm.threadMgr.borrowed_futures[(self.store_id, self.borrow_depth)] is not self:
+                    charm.threadMgr.borrowed_futures[(self.store_id, self.borrow_depth)].num_borrowers += 1
+            else:
+                charm.threadMgr.borrowed_futures[(self.store_id, self.borrow_depth)] = self
         return (self.fid, self.src, self.store, self.borrow_depth, charm.myPe())
 
     def __setstate__(self, state):
@@ -173,18 +179,19 @@ def __setstate__(self, state):
             self.store_id = (self.src << 32) + self.fid
         else:
             self.store_id = 0
+        # print("Setting state for id", self.store_id, "on pe", charm.myPe(), "at depth", self.borrow_depth)
         self._requested = False
         self.num_borrowers = 0
 
     def __del__(self):
         if self.store:
             if self.parent == None and self.num_borrowers == 0:
                 # This is the owner, delete the object from the object store
-                #print("Deleting owner", self.store_id)
+                # print("Deleting owner", self.store_id)
                 self.delete_object()
             else:
                 # this is a borrower, notify its parent of the deletion
-                #print("Deleting", self.store_id, "from", charm.myPe(), "sending notify to", self.parent)
+                # print("Deleting", self.store_id, "from", charm.myPe(), "sending notify to", self.parent, "at depth", self.borrow_depth)
                 charm.thisProxy[self.parent].notify_future_deletion(self.store_id, self.borrow_depth - 1)
 
 

docs/pool.rst

@@ -17,7 +17,8 @@ or creating more processes than processors.
 
     ``charm.pool`` is experimental,
     the API and performance (especially at large scales) is still subject to
-    change.
+    change. Additionally, do not include any Future objects in the iterable provided
+    to map or map_async, unless you set is_ray to True.
 
 .. note::
 

examples/pool/pool_fibonacci.py

@@ -9,6 +9,9 @@ def fib(n):
     return sum(charm.pool.map(fib, [n-1, n-2]))
 
 def main(args):
+    if(charm.numPes()==1):
+        print("Error: Run with more than one PE (exiting). For documentation on using pools, see: https://charm4py.readthedocs.io/en/latest/pool.html")
+        exit()
     print('fibonacci(13)=', fib(13))
     exit()
 

examples/pool/pool_simple.py

@@ -9,8 +9,11 @@ def twice(x):
 
 def main(args):
     ray.init()
-    results = charm.pool.map_async(square, [4], chunksize=1, multi_future=True)
-    results_twice = charm.pool.map_async(twice, results, chunksize=1, multi_future=True)
+    if(charm.numPes()==1):
+        print("Error: Run with more than one PE (exiting). For documentation on using pools, see: https://charm4py.readthedocs.io/en/latest/pool.html")
+        exit()
+    results = charm.pool.map_async(square, [4], chunksize=1, multi_future=True, is_ray=True)
+    results_twice = charm.pool.map_async(twice, results, chunksize=1, multi_future=True, is_ray=True)
 
     for x in results_twice:
         print(x.get())