ui/spice: Add an option to submit gl_draw requests at fixed rate

In the specific case where the display layer (virtio-gpu) is using
dmabuf, and if remote clients are enabled (-spice gl=on,port=xxxx),
it makes sense to limit the maximum (streaming) rate (refresh rate)
to a fixed value using the GUI refresh timer. Otherwise, the updates
or gl_draw requests would be sent as soon as the Guest submits a new
frame which is not optimal as it would lead to increased network
traffic and wastage of GPU cycles if the frames get dropped.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Cc: Michael Scherle <michael.scherle@rz.uni-freiburg.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Message-Id: <20250617043546.1022779-5-vivek.kasireddy@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/ui/spice-display.h b/include/ui/spice-display.h
index 6c55f38c8b..9bdde78266 100644
--- a/include/ui/spice-display.h
+++ b/include/ui/spice-display.h
@@ -152,6 +152,7 @@ struct SimpleSpiceCursor {
 
 extern bool spice_opengl;
 extern bool spice_remote_client;
+extern int spice_max_refresh_rate;
 
 int qemu_spice_rect_is_empty(const QXLRect* r);
 void qemu_spice_rect_union(QXLRect *dest, const QXLRect *r);