Add smooth profiler for redraw

src/graphics.rs

@@ -1,3 +1,6 @@
+use std::collections::VecDeque;
+use std::time::Duration;
+
 use alacritty_terminal::ansi::{Color, NamedColor};
 use alacritty_terminal::term::cell::{Cell, Flags as CellFlags};
 use alacritty_terminal::term::color::{Colors, Rgb};
@@ -246,6 +249,8 @@ pub struct Graphics {
     pub colors: Colors,
     glyph_cache: GlyphCache,
     cell_cache: HashMap<Point, GlyphInfo>,
+    redraw_profiler: Profiler,
+    present_profiler: Profiler,
 }
 
 impl Graphics {
@@ -267,6 +272,8 @@ impl Graphics {
             glyph_cache,
             cell_cache,
             colors,
+            redraw_profiler: Profiler::new("redraw", 300),
+            present_profiler: Profiler::new("present", 300),
         }
     }
 
@@ -419,10 +426,40 @@ impl Graphics {
             }
         }
 
-        let copy_start = std::time::Instant::now();
-        context.set_buffer(&self.canvas.buffer, width as u16, height as u16);
-        log::debug!("buffer copy time: {:?}", copy_start.elapsed());
+        self.redraw_profiler.push(start.elapsed());
 
-        log::debug!("redraw() time: {:?}", start.elapsed());
+        let present_start = std::time::Instant::now();
+        context.set_buffer(&self.canvas.buffer, width as u16, height as u16);
+        self.present_profiler.push(present_start.elapsed());
+    }
+}
+
+pub struct Profiler {
+    name: String,
+    limit: usize,
+    sum: Duration,
+    ring: VecDeque<Duration>,
+}
+
+impl Profiler {
+    pub fn new(name: &str, limit: usize) -> Self {
+        Self {
+            name: name.to_string(),
+            limit,
+            sum: Duration::ZERO,
+            ring: VecDeque::with_capacity(limit),
+        }
+    }
+
+    pub fn push(&mut self, time: Duration) {
+        if self.ring.len() == self.limit {
+            self.sum -= self.ring.pop_front().unwrap();
+        }
+
+        self.sum += time;
+        self.ring.push_back(time);
+
+        let average = self.sum.div_f32(self.ring.len() as f32);
+        log::debug!("{} time: {:?}", self.name, average);
     }
 }