From 3b22ae9021117927f42e3ae0d8876933fb5239be Mon Sep 17 00:00:00 2001
From: Kevin Huck <khuck@cs.uoregon.edu>
Date: Thu, 22 Mar 2018 14:56:32 -0700
Subject: [PATCH] Adding parent dependencies for hpx threads.

---
 CMakeLists.txt                      |  2 ++
 hpx/runtime/threads/thread_data.hpp |  8 +++++++-
 hpx/util/apex.hpp                   | 16 ++++++++--------
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a66d4d69104..2056630209e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1535,6 +1535,8 @@ if(HPX_WITH_APEX_NO_UPDATE)
   set(_hpx_apex_no_update NO_UPDATE)
 endif()
 if(HPX_WITH_APEX)
+  # We want to track parent dependencies
+  hpx_add_config_define(HPX_HAVE_THREAD_PARENT_REFERENCE)
   # handle APEX library
   include(GitExternal)
   git_external(apex
diff --git a/hpx/runtime/threads/thread_data.hpp b/hpx/runtime/threads/thread_data.hpp
index 6e2a89633f6..faff986f493 100644
--- a/hpx/runtime/threads/thread_data.hpp
+++ b/hpx/runtime/threads/thread_data.hpp
@@ -604,7 +604,13 @@ namespace hpx { namespace threads
                 parent_locality_id_ = get_locality_id();
 #endif
 #if defined(HPX_HAVE_APEX)
-            set_apex_data(apex_new_task(get_description()));
+            if (parent_thread_id_) {
+                set_apex_data(apex_new_task(get_description(),
+                    parent_thread_id_.get()->get_apex_data()));
+            } else {
+                set_apex_data(apex_new_task(get_description(),
+                    nullptr));
+            }
 #endif
             HPX_ASSERT(init_data.stacksize != 0);
             HPX_ASSERT(coroutine_.is_ready());
diff --git a/hpx/util/apex.hpp b/hpx/util/apex.hpp
index 4ccdd6f72f8..571171b2ae2 100644
--- a/hpx/util/apex.hpp
+++ b/hpx/util/apex.hpp
@@ -36,21 +36,19 @@ namespace hpx { namespace util
     }
 
     inline void * apex_new_task(
-                thread_description const& description)
+                thread_description const& description,
+                void * parent_task)
     {
         if (description.kind() ==
                 thread_description::data_type_description) {
-            return (void*)apex::new_task(description.get_description());
+            return (void*)apex::new_task(description.get_description(),
+                UINTMAX_MAX, (apex::task_wrapper*)parent_task);
         } else {
-            return (void*)apex::new_task(description.get_address());
+            return (void*)apex::new_task(description.get_address(),
+                UINTMAX_MAX, (apex::task_wrapper*)parent_task);
         }
     }
 
-    inline void * apex_new_task(char const* name)
-    {
-        return (void*)apex::new_task(name);
-    }
-
     inline void * apex_update_task(void * wrapper,
                 thread_description const& description)
     {
@@ -68,6 +66,8 @@ namespace hpx { namespace util
         return (void*)apex::update_task((apex::task_wrapper*)wrapper, name);
     }
 
+    /* This is a scoped object around task scheduling to measure the time
+     * spent executing hpx threads */
     struct apex_wrapper
     {
         apex_wrapper(void* const data_ptr) : stopped(false), data_(nullptr)