#769: gossiplb: use reduction instead for sync

DARMA-tasking · Apr 15, 2020 · 442e579 · 442e579
1 parent 0e025b0
commit 442e579
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/src/vt/vrt/collection/balance/gossiplb/gossiplb.cc b/src/vt/vrt/collection/balance/gossiplb/gossiplb.cc
@@ -183,7 +183,15 @@ void GossipLB::inform() {
     k_max_, k_cur_, is_underloaded_, is_overloaded_, this_new_load_
   );
 
-  theCollective()->barrier();
+  setup_done_ = false;
+
+  auto cb = theCB()->makeBcast<GossipLB, ReduceMsgType, &GossipLB::setupDone>(proxy_);
+  auto msg = makeMessage<ReduceMsgType>();
+  proxy_.reduce(msg.get(), cb);
+
+  while (not setup_done_) {
+    vt::runScheduler();
+  }
 
   bool inform_done = false;
   auto propagate_epoch = theTerm()->makeEpochCollective("GossipLB: inform");
@@ -207,6 +215,10 @@ void GossipLB::inform() {
   );
 }
 
+void GossipLB::setupDone(ReduceMsgType* msg) {
+  setup_done_ = true;
+}
+
 void GossipLB::propagateRound(EpochType epoch) {
   debug_print(
     gossiplb, node,

diff --git a/src/vt/vrt/collection/balance/gossiplb/gossiplb.h b/src/vt/vrt/collection/balance/gossiplb/gossiplb.h
@@ -58,9 +58,10 @@
 namespace vt { namespace vrt { namespace collection { namespace lb {
 
 struct GossipLB : BaseLB {
-  using GossipMsg   = balance::GossipMsg;
-  using NodeSetType = std::vector<NodeType>;
-  using ObjsType    = std::unordered_map<ObjIDType, LoadType>;
+  using GossipMsg     = balance::GossipMsg;
+  using NodeSetType   = std::vector<NodeType>;
+  using ObjsType      = std::unordered_map<ObjIDType, LoadType>;
+  using ReduceMsgType = vt::collective::ReduceNoneMsg;
 
   GossipLB() = default;
 
@@ -96,6 +97,8 @@ struct GossipLB : BaseLB {
   void inLazyMigrations(balance::LazyMigrationMsg* msg);
   void thunkMigrations();
 
+  void setupDone(ReduceMsgType* msg);
+
 private:
   uint8_t f_                                        = 4;
   uint8_t k_max_                                    = 4;
@@ -112,6 +115,7 @@ struct GossipLB : BaseLB {
   std::unordered_map<ObjIDType, TimeType> cur_objs_ = {};
   LoadType this_new_load_                           = 0.0;
   CriterionEnum criterion_                          = CriterionEnum::ModifiedGrapevine;
+  bool setup_done_                                  = false;
 };
 
 }}}} /* end namespace vt::vrt::collection::lb */