Merge pull request #1899 from STEllAR-GROUP/fixing_1898

Fixing a problem with credit splitting as revealed by #1898

hpx/lcos/future.hpp

@@ -127,6 +127,16 @@ namespace hpx { namespace lcos { namespace detail
 
                 ar.await_future(f);
             }
+            else
+            {
+                if(f.is_ready() && f.has_value())
+                {
+                    value_type const & value =
+                        *hpx::traits::future_access<Future>::
+                            get_shared_state(f)->get_result();
+                    ar << value;
+                }
+            }
             return;
         }
 

hpx/runtime/parcelset/parcelport_impl.hpp

@@ -200,8 +200,29 @@ namespace hpx { namespace parcelset
                     new hpx::serialization::output_archive(
                         *future_await, 0, 0, 0, 0, &future_await->new_gids_)
                 );
+
+            put_parcel_await(
+                dest, std::move(p), std::move(f), trigger, archive, future_await);
+        }
+
+        void put_parcel_await(
+            locality const & dest, parcel p, write_handler_type f, bool trigger
+          , boost::shared_ptr<hpx::serialization::output_archive> const & archive
+          , boost::shared_ptr<
+                hpx::serialization::detail::future_await_container
+            > const & future_await)
+        {
+            future_await->reset();
+
             (*archive) << p;
 
+            // We are doing a fixed point iteration until we are sure that the
+            // serialization process requires nothing more to wait on ...
+            // Things where we need waiting:
+            //  - (shared_)future<id_type>: when the future wasn't ready yet, we
+            //      need to do another await round for the id splitting
+            //  - id_type: we need to await, if and only if, the credit of the
+            //      needs to split.
             if(future_await->has_futures())
             {
                 void (parcelport_impl::*awaiter)(
@@ -210,7 +231,7 @@ namespace hpx { namespace parcelset
                   , boost::shared_ptr<
                         hpx::serialization::detail::future_await_container> const &
                 )
-                    = &parcelport_impl::put_parcel_impl;
+                    = &parcelport_impl::put_parcel_await;
                 (*future_await)(
                     util::bind(
                         util::one_shot(awaiter), this,

hpx/runtime/serialization/detail/future_await_container.hpp

@@ -49,7 +49,7 @@ namespace hpx { namespace serialization { namespace detail
             // hpx::lcos::local::promise<void>::set_value() might need to acquire
             // a lock, as such, we check the our triggering condition inside a
             // critical section and trigger the promise outside of it.
-            bool set_value = true;
+            bool set_value = false;
             {
                 boost::lock_guard<mutex_type> l(mtx_);
                 ++triggered_futures_;
@@ -75,6 +75,14 @@ namespace hpx { namespace serialization { namespace detail
             );
         }
 
+        void reset()
+        {
+            done_ = false;
+            num_futures_ = 0;
+            triggered_futures_ = 0;
+            promise_ = hpx::lcos::local::promise<void>();
+        }
+
         bool has_futures()
         {
             if(num_futures_ == 0)

tests/regressions/lcos/CMakeLists.txt

@@ -18,6 +18,7 @@ set(tests
     future_hang_on_get_629
     future_hang_on_then_629
     future_timed_wait_1025
+    future_serialization_1898
     future_unwrap_878
     future_unwrap_1182
     ignore_while_locked_1485

tests/regressions/lcos/future_serialization_1898.cpp

@@ -0,0 +1,88 @@
+//  Copyright (c) 2015 Thomas Heller
+//
+//  Distributed under the Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <hpx/hpx_main.hpp>
+#include <hpx/include/actions.hpp>
+#include <hpx/include/components.hpp>
+#include <hpx/lcos/future.hpp>
+
+#include <hpx/util/lightweight_test.hpp>
+
+struct test_server
+    : hpx::components::component_base<test_server>
+{
+    test_server() { alive++; }
+    ~test_server() { alive--; }
+
+    static boost::atomic<int> alive;
+};
+
+typedef hpx::components::component<test_server> server_type;
+HPX_REGISTER_COMPONENT(server_type, test_server);
+
+boost::atomic<int> test_server::alive(0);
+
+hpx::id_type test(hpx::future<hpx::id_type> fid)
+{
+    hpx::id_type id = fid.get();
+    HPX_TEST(hpx::naming::detail::gid_was_split(id.get_gid()));
+    return id;
+}
+
+HPX_PLAIN_ACTION(test);
+
+int main()
+{
+    hpx::id_type loc = hpx::find_here();
+    {
+        HPX_TEST(test_server::alive == 0);
+        hpx::id_type gid = hpx::new_<test_server>(loc).get();
+        HPX_TEST(test_server::alive == 1);
+//         HPX_TEST(!hpx::naming::detail::gid_was_split(gid.get_gid()));
+
+        auto remote_localities = hpx::find_remote_localities();
+        for(hpx::id_type loc : remote_localities)
+        {
+            {
+                hpx::future<hpx::id_type> test_fid = hpx::make_ready_future(gid);
+                hpx::future<hpx::id_type> fid
+                    = hpx::async(test_action(), loc, std::move(test_fid));
+                HPX_TEST(test_server::alive == 1);
+
+                hpx::id_type new_gid = fid.get();
+                HPX_TEST_NEQ(
+                    hpx::naming::detail::get_credit_from_gid(gid.get_gid())
+                  , hpx::naming::detail::get_credit_from_gid(new_gid.get_gid())
+                );
+            }
+
+            {
+                hpx::lcos::local::promise<hpx::id_type> pid;
+
+                hpx::future<hpx::id_type> test_fid = pid.get_future();
+                hpx::future<hpx::id_type> fid
+                    = hpx::async(test_action(), loc, std::move(test_fid));
+                HPX_TEST(test_server::alive == 1);
+
+                hpx::this_thread::yield();
+
+                pid.set_value(gid);
+                HPX_TEST(test_server::alive == 1);
+
+                hpx::id_type new_gid = fid.get();
+                HPX_TEST_NEQ(
+                    hpx::naming::detail::get_credit_from_gid(gid.get_gid())
+                  , hpx::naming::detail::get_credit_from_gid(new_gid.get_gid())
+                );
+            }
+
+
+            HPX_TEST(test_server::alive == 1);
+        }
+        HPX_TEST(test_server::alive == 1);
+    }
+
+    return 0;
+}