Optimize Parameter Control Loop

For plugins with 10000 Control Inputs, dynamic_pointer_cast<> overhead
is significant, here ~2msec (~0.2usec per cast, optimized build, i7-5600U,
2.60GHz)

diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 983d3b9aa8ae3c411640881504c8c8ff9c16c90e..5ecf652ce37aa6393d0199b4bf690f628bae7f55 100644 (file)
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -882,29 +882,20 @@ PluginInsert::connect_and_run (BufferSet& bufs, samplepos_t start, samplepos_t e
 
                uint32_t n = 0;
 
-               for (Controls::iterator li = controls().begin(); li != controls().end(); ++li, ++n) {
-
-                       boost::shared_ptr<AutomationControl> c
-                               = boost::dynamic_pointer_cast<AutomationControl>(li->second);
-
-                       if (c->list() && c->automation_playback()) {
+               for (Controls::const_iterator li = controls().begin(); li != controls().end(); ++li, ++n) {
+
+                       /* boost::dynamic_pointer_cast<> has significant overhead, since we know that
+                        * all controls are AutomationControl and their lists - if any - are AutomationList,
+                        * we can use static_cast<>. This yields a speedup of 2.8/4.6 over to the
+                        * previous code (measuerd with VeeSeeVSTRack 10k parameters, optimized build) */
+                       AutomationControl& c = static_cast<AutomationControl&> (*(li->second));
+                       boost::shared_ptr<const Evoral::ControlList> clist (c.list());
+                       if (clist && (static_cast<AutomationList const&> (*clist)).automation_playback ()) {
                                bool valid;
-
-                               const float val = c->list()->rt_safe_eval (start, valid);
-
+                               const float val = c.list()->rt_safe_eval (start, valid);
                                if (valid) {
-                                       /* This is the ONLY place where we are
-                                        *  allowed to call
-                                        *  AutomationControl::set_value_unchecked(). We
-                                        *  know that the control is in
-                                        *  automation playback mode, so no
-                                        *  check on writable() is required
-                                        *  (which must be done in AutomationControl::set_value()
-                                        *
-                                        */
-                                       c->set_value_unchecked(val);
+                                       c.set_value_unchecked(val);
                                }
-
                        }
                }
        }