From 8471af5a7d092c9280cba5427f3a550bf0b4de32 Mon Sep 17 00:00:00 2001
From: Mikayla Maki <mikayla.c.maki@icloud.com>
Date: Thu, 28 Jul 2022 16:03:00 -0700
Subject: [PATCH] Improved render performance implementation to use a fork of
 alacritty which includes the last # of bytes processed as a way of estimating
 throughput in cases where the terminal output is chanegd in place

---
 Cargo.lock                      |  4 ++--
 crates/terminal/Cargo.toml      |  2 +-
 crates/terminal/src/terminal.rs | 19 +++++++++----------
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 2c2f71b544..d6310d76db 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -62,7 +62,7 @@ dependencies = [
 [[package]]
 name = "alacritty_config_derive"
 version = "0.1.0"
-source = "git+https://github.com/zed-industries/alacritty?rev=382e1892c4eaae7d45ec6ea580db47242ec66e31#382e1892c4eaae7d45ec6ea580db47242ec66e31"
+source = "git+https://github.com/zed-industries/alacritty?rev=ba56f545e3e3606af0112c6bdfe998baf7faab50#ba56f545e3e3606af0112c6bdfe998baf7faab50"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -72,7 +72,7 @@ dependencies = [
 [[package]]
 name = "alacritty_terminal"
 version = "0.17.0-dev"
-source = "git+https://github.com/zed-industries/alacritty?rev=382e1892c4eaae7d45ec6ea580db47242ec66e31#382e1892c4eaae7d45ec6ea580db47242ec66e31"
+source = "git+https://github.com/zed-industries/alacritty?rev=ba56f545e3e3606af0112c6bdfe998baf7faab50#ba56f545e3e3606af0112c6bdfe998baf7faab50"
 dependencies = [
  "alacritty_config_derive",
  "base64 0.13.0",
diff --git a/crates/terminal/Cargo.toml b/crates/terminal/Cargo.toml
index e6d25f495b..354952481b 100644
--- a/crates/terminal/Cargo.toml
+++ b/crates/terminal/Cargo.toml
@@ -8,7 +8,7 @@ path = "src/terminal.rs"
 doctest = false
 
 [dependencies]
-alacritty_terminal = { git = "https://github.com/zed-industries/alacritty", rev = "382e1892c4eaae7d45ec6ea580db47242ec66e31"}
+alacritty_terminal = { git = "https://github.com/zed-industries/alacritty", rev = "ba56f545e3e3606af0112c6bdfe998baf7faab50"}
 editor = { path = "../editor" }
 util = { path = "../util" }
 gpui = { path = "../gpui" }
diff --git a/crates/terminal/src/terminal.rs b/crates/terminal/src/terminal.rs
index d7efecc486..d26f694abf 100644
--- a/crates/terminal/src/terminal.rs
+++ b/crates/terminal/src/terminal.rs
@@ -13,7 +13,7 @@ use alacritty_terminal::{
     ansi::{ClearMode, Handler},
     config::{Config, Program, PtyConfig, Scrolling},
     event::{Event as AlacTermEvent, EventListener, Notify, WindowSize},
-    event_loop::{EventLoop, Msg, Notifier},
+    event_loop::{EventLoop, Msg, Notifier, READ_BUFFER_SIZE},
     grid::{Dimensions, Scroll},
     index::{Direction, Point},
     selection::{Selection, SelectionType},
@@ -55,7 +55,7 @@ const DEBUG_TERMINAL_WIDTH: f32 = 500.;
 const DEBUG_TERMINAL_HEIGHT: f32 = 30.; //This needs to be wide enough that the CI & a local dev's prompt can fill the whole space.
 const DEBUG_CELL_WIDTH: f32 = 5.;
 const DEBUG_LINE_HEIGHT: f32 = 5.;
-const MAX_FRAME_RATE: f32 = 120.;
+const MAX_FRAME_RATE: f32 = 60.;
 const BACK_BUFFER_SIZE: usize = 5000;
 
 ///Upward flowing events, for changing the title and such
@@ -412,7 +412,7 @@ impl Terminal {
 
     ///Tells the render loop how many frames to skip before reading from the terminal.
     fn frames_to_skip(&self) -> usize {
-        self.frames_to_skip
+        0 //self.frames_to_skip
     }
 
     fn push_events(&mut self, events: Vec<AlacTermEvent>) {
@@ -570,17 +570,16 @@ impl Terminal {
             self.process_terminal_event(&e, &mut term, cx)
         }
 
-        let buffer_velocity = term.grid().history_size().saturating_sub(BACK_BUFFER_SIZE);
-
-        let fractional_velocity = buffer_velocity as f32 / BACK_BUFFER_SIZE as f32;
+        //TODO: determine a better metric for this
+        let buffer_velocity =
+            (term.last_processed_bytes() as f32 / (READ_BUFFER_SIZE as f32 / 4.)).clamp(0., 1.);
 
         //2nd power
-        let scaled_fraction = fractional_velocity * fractional_velocity;
+        let scaled_velocity = buffer_velocity * buffer_velocity;
 
-        self.frames_to_skip = (scaled_fraction * (Self::default_fps() / 10.)).round() as usize;
+        self.frames_to_skip = (scaled_velocity * (Self::default_fps() / 10.)).round() as usize;
 
-        term.grid_mut().update_history(BACK_BUFFER_SIZE); //Clear out the measurement space
-        term.grid_mut().update_history(BACK_BUFFER_SIZE * 2); //Extra space for measuring
+        term.set_last_processed_bytes(0); //Clear it in case no reads between this lock and the next.
 
         let content = term.renderable_content();