linux/x11: Prioritize rendering in X11 event loop (#13468)

Thorsten Ball created 2 years ago

This is a small change that aims to address frames being dropped when we
get a ton of X11 input events.

What it does, in short, is to first read all X11 input events and then
prioritize the rendering.

In my testing, it causes less frames to be dropped when the system is
under heavy load and lots of input events are being created.

Release Notes:

- N/A

Change summary

crates/gpui/src/platform/linux/x11/client.rs | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

Detailed changes

crates/gpui/src/platform/linux/x11/client.rs

@@ -1,4 +1,5 @@
 use std::cell::RefCell;
+use std::collections::HashSet;
 use std::ffi::OsString;
 use std::ops::Deref;
 use std::rc::{Rc, Weak};
@@ -298,7 +299,24 @@ impl X11Client {
                 {
                     let xcb_connection = xcb_connection.clone();
                     move |_readiness, _, client| {
+                        let mut events = Vec::new();
+                        let mut windows_to_refresh = HashSet::new();
+
                         while let Some(event) = xcb_connection.poll_for_event()? {
+                            if let Event::Expose(event) = event {
+                                windows_to_refresh.insert(event.window);
+                            } else {
+                                events.push(event);
+                            }
+                        }
+
+                        for window in windows_to_refresh.into_iter() {
+                            if let Some(window) = client.get_window(window) {
+                                window.refresh();
+                            }
+                        }
+
+                        for event in events.into_iter() {
                             let mut state = client.0.borrow_mut();
                             if state.ximc.is_none() || state.xim_handler.is_none() {
                                 drop(state);