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combine short periodic timeout functions for windows. 

Fixes excessive CPU usage (spinlock instead of sleep/WaitForSingleObject)

MS Windows has a scheduler time-slice of 15ms.
Ardour has two fast timeout functions: The FPS timeout (20-60Hz, clock
video-monitor) and a fast-screen-update (25Hz, meters etc).
They are loosely coupled (async) and scheduled from the main application
thread (gtk main).

Since they're async, gtk schedules them as needed. Even though the actual
period of the separate timeouts is larger. The effective period between
all timeout callbacks is <15ms and the main application thread never idles.
This commit is contained in:
Robin Gareus 2014-10-25 19:21:15 +02:00
parent e02efddb21
commit baea04713f
2 changed files with 19 additions and 0 deletions
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15
gtk2_ardour/ardour_ui.cc
View File

@ -1006,7 +1006,9 @@ If you still wish to quit, please use the\n\n\
second_connection.disconnect ();
point_one_second_connection.disconnect ();
#ifndef PLATFORM_WINDOWS
point_zero_something_second_connection.disconnect();
#endif
fps_connection.disconnect();
}
@ -1159,6 +1161,9 @@ gint
ARDOUR_UI::every_fps ()
{
FPSUpdate(); /* EMIT_SIGNAL */
#ifdef PLATFORM_WINDOWS
every_point_zero_something_seconds();
#endif
return TRUE;
}
@ -1178,7 +1183,17 @@ ARDOUR_UI::set_fps_timeout_connection ()
* _session->frame_rate() / _session->nominal_frame_rate()
/ _session->timecode_frames_per_second()
);
#ifdef PLATFORM_WINDOWS
// the smallest windows scheduler time-slice is ~15ms.
// periodic GUI timeouts shorter than that will cause
// WaitForSingleObject to spinlock (100% of one CPU Core)
// and gtk never enters idle mode.
// also changing timeBeginPeriod(1) does not affect that in
// any beneficial way, so we just limit the max rate for now.
interval = std::max(30u, interval); // at most ~33Hz.
#else
interval = std::max(8u, interval); // at most 120Hz.
#endif
}
fps_connection.disconnect();
fps_connection = Glib::signal_timeout().connect (sigc::mem_fun(*this, &ARDOUR_UI::every_fps), interval);

4
gtk2_ardour/ardour_ui_dialogs.cc
View File

@ -184,7 +184,9 @@ ARDOUR_UI::set_session (Session *s)
second_connection = Glib::signal_timeout().connect (sigc::mem_fun(*this, &ARDOUR_UI::every_second), 1000);
point_one_second_connection = Glib::signal_timeout().connect (sigc::mem_fun(*this, &ARDOUR_UI::every_point_one_seconds), 100);
#ifndef PLATFORM_WINDOWS
point_zero_something_second_connection = Glib::signal_timeout().connect (sigc::mem_fun(*this, &ARDOUR_UI::every_point_zero_something_seconds), 40);
#endif
set_fps_timeout_connection();
update_format ();
@ -286,7 +288,9 @@ ARDOUR_UI::unload_session (bool hide_stuff)
second_connection.disconnect ();
point_one_second_connection.disconnect ();
#ifndef PLATFORM_WINDOWS
point_zero_something_second_connection.disconnect();
#endif
fps_connection.disconnect();
if (editor_meter) {