[gegl] gegl-stats: add assigned-threads stat

[Ell <ell src gnome org>]

commit fc532f06773bd292c86abee31ac18f62e26d39df
Author: Ell <ell_se yahoo com>
Date:   Tue Jul 23 17:09:27 2019 +0300

    gegl-stats: add assigned-threads stat
    
    ... which reports the number of worker threads which currently have
    work assigned.  This can be larger than active-threads, if worker
    threads that have been assigned work had already finished it, but
    the operation as a whole is not finished yet.

 gegl/gegl-parallel-private.h |  1 +
 gegl/gegl-parallel.c         | 11 +++++++++++
 gegl/gegl-stats.c            | 12 ++++++++++++
 3 files changed, 24 insertions(+)
---
diff --git a/gegl/gegl-parallel-private.h b/gegl/gegl-parallel-private.h
index 5d5c69f50..e355959b6 100644
--- a/gegl/gegl-parallel-private.h
+++ b/gegl/gegl-parallel-private.h
@@ -34,6 +34,7 @@ gint      gegl_parallel_distribute_get_optimal_n_threads (gdouble n_elements,
 
 /*  stats  */
 
+gint      gegl_parallel_get_n_assigned_worker_threads    (void);
 gint      gegl_parallel_get_n_active_worker_threads      (void);
 
 
diff --git a/gegl/gegl-parallel.c b/gegl/gegl-parallel.c
index 9012c1c6c..8703b3de1 100644
--- a/gegl/gegl-parallel.c
+++ b/gegl/gegl-parallel.c
@@ -74,6 +74,7 @@ static GMutex                       gegl_parallel_distribute_completion_mutex;
 static GCond                        gegl_parallel_distribute_completion_cond;
 static volatile gint                gegl_parallel_distribute_completion_counter;
 static volatile gint                gegl_parallel_distribute_busy;
+static gint                         gegl_parallel_distribute_n_assigned_threads;
 
 static gdouble                      gegl_parallel_distribute_thread_time;
 
@@ -173,6 +174,8 @@ gegl_parallel_distribute (gint                       max_n,
   task.func      = func;
   task.user_data = user_data;
 
+  gegl_parallel_distribute_n_assigned_threads = task.n - 1;
+
   g_atomic_int_set (&gegl_parallel_distribute_completion_counter, task.n - 1);
 
   for (i = 0; i < task.n - 1; i++)
@@ -205,6 +208,8 @@ gegl_parallel_distribute (gint                       max_n,
       g_mutex_unlock (&gegl_parallel_distribute_completion_mutex);
     }
 
+  gegl_parallel_distribute_n_assigned_threads = 0;
+
   g_atomic_int_set (&gegl_parallel_distribute_busy, 0);
 }
 
@@ -362,6 +367,12 @@ gegl_parallel_distribute_area (const GeglRectangle            *area,
 /*  public functions (stats)  */
 
 
+gint
+gegl_parallel_get_n_assigned_worker_threads (void)
+{
+  return gegl_parallel_distribute_n_assigned_threads;
+}
+
 gint
 gegl_parallel_get_n_active_worker_threads (void)
 {
diff --git a/gegl/gegl-stats.c b/gegl/gegl-stats.c
index bad4a194b..e336ee555 100644
--- a/gegl/gegl-stats.c
+++ b/gegl/gegl-stats.c
@@ -54,6 +54,7 @@ enum
   PROP_ZOOM_TOTAL,
   PROP_TILE_ALLOC_TOTAL,
   PROP_SCRATCH_TOTAL,
+  PROP_ASSIGNED_THREADS,
   PROP_ACTIVE_THREADS
 };
 
@@ -217,6 +218,13 @@ gegl_stats_class_init (GeglStatsClass *klass)
                                                         0, G_MAXUINT64, 0,
                                                         G_PARAM_READABLE));
 
+  g_object_class_install_property (object_class, PROP_ASSIGNED_THREADS,
+                                   g_param_spec_int ("assigned-threads",
+                                                     "Assigned threads",
+                                                     "Number of assigned worker threads",
+                                                     0, G_MAXINT, 0,
+                                                     G_PARAM_READABLE));
+
   g_object_class_install_property (object_class, PROP_ACTIVE_THREADS,
                                    g_param_spec_int ("active-threads",
                                                      "Active threads",
@@ -328,6 +336,10 @@ gegl_stats_get_property (GObject    *object,
         g_value_set_uint64 (value, gegl_scratch_get_total ());
         break;
 
+      case PROP_ASSIGNED_THREADS:
+        g_value_set_int (value, gegl_parallel_get_n_assigned_worker_threads ());
+        break;
+
       case PROP_ACTIVE_THREADS:
         g_value_set_int (value, gegl_parallel_get_n_active_worker_threads ());
         break;