Block the emulator thread when idle

Cargo.lock

@@ -42,9 +42,9 @@ dependencies = [
 
 [[package]]
 name = "allocator-api2"
-version = "0.2.18"
+version = "0.2.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c6cb57a04249c6480766f7f7cef5467412af1490f8d1e243141daddada3264f"
+checksum = "611cc2ae7d2e242c457e4be7f97036b8ad9ca152b499f53faf99b1ed8fc2553f"
 
 [[package]]
 name = "alsa"
@@ -106,9 +106,9 @@ dependencies = [
 
 [[package]]
 name = "anstream"
-version = "0.6.17"
+version = "0.6.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23a1e53f0f5d86382dafe1cf314783b2044280f406e7e1506368220ad11b1338"
+checksum = "8acc5369981196006228e28809f761875c0327210a891e941f4c683b3a99529b"
 dependencies = [
  "anstyle",
  "anstyle-parse",
@@ -155,9 +155,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.92"
+version = "1.0.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74f37166d7d48a0284b99dd824694c26119c700b53bf0d1540cdb147dbdaaf13"
+checksum = "4c95c10ba0b00a02636238b814946408b1322d5ac4760326e6fb8ec956d85775"
 
 [[package]]
 name = "arrayref"
@@ -324,9 +324,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.1.34"
+version = "1.1.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67b9470d453346108f93a59222a9a1a5724db32d0a4727b7ab7ace4b4d822dc9"
+checksum = "40545c26d092346d8a8dab71ee48e7685a7a9cba76e634790c215b41a4a7b4cf"
 dependencies = [
  "jobserver",
  "libc",
@@ -860,9 +860,9 @@ dependencies = [
 
 [[package]]
 name = "hashbrown"
-version = "0.15.0"
+version = "0.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e087f84d4f86bf4b218b927129862374b72199ae7d8657835f1e89000eea4fb"
+checksum = "3a9bfc1af68b1726ea47d3d5109de126281def866b33970e10fbab11b5dafab3"
 
 [[package]]
 name = "hassle-rs"
@@ -960,7 +960,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "707907fe3c25f5424cce2cb7e1cbcafee6bdbe735ca90ef77c29e84591e5b9da"
 dependencies = [
  "equivalent",
- "hashbrown 0.15.0",
+ "hashbrown 0.15.1",
 ]
 
 [[package]]
@@ -1046,9 +1046,9 @@ checksum = "e2db585e1d738fc771bf08a151420d3ed193d9d895a36df7f6f8a9456b911ddc"
 
 [[package]]
 name = "libc"
-version = "0.2.161"
+version = "0.2.162"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e9489c2807c139ffd9c1794f4af0ebe86a828db53ecdc7fea2111d0fed085d1"
+checksum = "18d287de67fe55fd7e1581fe933d965a5a9477b38e949cfa9f8574ef01506398"
 
 [[package]]
 name = "libloading"
@@ -1673,9 +1673,9 @@ checksum = "953ec861398dccce10c670dfeaf3ec4911ca479e9c02154b3a215178c5f566f2"
 
 [[package]]
 name = "polling"
-version = "3.7.3"
+version = "3.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc2790cd301dec6cd3b7a025e4815cf825724a51c98dccfe6a3e55f05ffb6511"
+checksum = "a604568c3202727d1507653cb121dbd627a58684eb09a820fd746bee38b4442f"
 dependencies = [
  "cfg-if",
  "concurrent-queue",
@@ -1881,9 +1881,9 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "0.38.38"
+version = "0.38.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa260229e6538e52293eeb577aabd09945a09d6d9cc0fc550ed7529056c2e32a"
+checksum = "99e4ea3e1cdc4b559b8e5650f9c8e5998e3e5c1343b4eaf034565f32318d63c0"
 dependencies = [
  "bitflags 2.6.0",
  "errno",
@@ -1892,6 +1892,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e819f2bc632f285be6d7cd36e25940d45b2391dd6d9b939e79de557f7014248"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -1972,8 +1978,10 @@ dependencies = [
  "pollster",
  "rtrb",
  "rubato",
+ "thread-priority",
  "wgpu",
  "winit",
+ "winver",
 ]
 
 [[package]]
@@ -2100,24 +2108,38 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.66"
+version = "1.0.69"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d171f59dbaa811dbbb1aee1e73db92ec2b122911a48e1390dfe327a821ddede"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.66"
+version = "1.0.69"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b08be0f17bd307950653ce45db00cd31200d82b624b36e181337d9c7d92765b5"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
 dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.87",
 ]
 
+[[package]]
+name = "thread-priority"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfe075d7053dae61ac5413a34ea7d4913b6e6207844fd726bdd858b37ff72bf5"
+dependencies = [
+ "bitflags 2.6.0",
+ "cfg-if",
+ "libc",
+ "log",
+ "rustversion",
+ "winapi",
+]
+
 [[package]]
 name = "tiny-skia"
 version = "0.11.4"
@@ -2615,6 +2637,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "windows"
+version = "0.48.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e686886bc078bc1b0b600cac0147aadb815089b6e4da64016cbd754b6342700f"
+dependencies = [
+ "windows-targets 0.48.5",
+]
+
 [[package]]
 name = "windows"
 version = "0.52.0"
@@ -2929,6 +2960,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "winver"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e0e7162b9e282fd75a0a832cce93994bdb21208d848a418cd05a5fdd9b9ab33"
+dependencies = [
+ "windows 0.48.0",
+]
+
 [[package]]
 name = "x11-dl"
 version = "2.21.0"
@@ -2988,9 +3028,9 @@ checksum = "b9cc00251562a284751c9973bace760d86c0276c471b4be569fe6b068ee97a56"
 
 [[package]]
 name = "xml-rs"
-version = "0.8.22"
+version = "0.8.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af4e2e2f7cba5a093896c1e150fbfe177d1883e7448200efb81d40b9d339ef26"
+checksum = "af310deaae937e48a26602b730250b4949e125f468f11e6990be3e5304ddd96f"
 
 [[package]]
 name = "zerocopy"

Cargo.toml

@@ -19,9 +19,13 @@ num-traits = "0.2"
 pollster = "0.4"
 rtrb = "0.3"
 rubato = "0.16"
+thread-priority = "1"
 wgpu = "22.1"
 winit = "0.30"
 
+[target."cfg(windows)".dependencies]
+winver = "1"
+
 [build-dependencies]
 cc = "1"
 

src/app/common.rs

@@ -8,7 +8,7 @@ use imgui::{FontSource, MouseCursor, SuspendedContext, WindowToken};
 use imgui_wgpu::{Renderer, RendererConfig};
 use imgui_winit_support::WinitPlatform;
 use pollster::block_on;
-#[cfg(target_os = "windows")]
+#[cfg(windows)]
 use winit::platform::windows::{CornerPreference, WindowAttributesExtWindows as _};
 use winit::{
     dpi::{LogicalSize, PhysicalSize, Size},
@@ -23,7 +23,7 @@ pub struct WindowStateBuilder<'a> {
 impl<'a> WindowStateBuilder<'a> {
     pub fn new(event_loop: &'a ActiveEventLoop) -> Self {
         let attributes = Window::default_attributes();
-        #[cfg(target_os = "windows")]
+        #[cfg(windows)]
         let attributes = attributes.with_corner_preference(CornerPreference::DoNotRound);
         Self {
             event_loop,
@@ -63,8 +63,17 @@ pub struct WindowState {
 
 impl WindowState {
     fn new(event_loop: &ActiveEventLoop, attributes: WindowAttributes) -> Self {
+        let backends = wgpu::Backends::PRIMARY;
+        #[cfg(windows)]
+        let backends = if winver::WindowsVersion::detect().is_some_and(|v| v.major >= 10) {
+            // DX12 is faster than GL, so don't use GL on windows versions which support DX12.
+            // When wgpu switches to default to DX12, this can be removed.
+            backends - wgpu::Backends::GL
+        } else {
+            backends
+        };
         let instance = wgpu::Instance::new(wgpu::InstanceDescriptor {
-            backends: wgpu::Backends::PRIMARY,
+            backends,
             ..Default::default()
         });
 

src/emulator.rs

@@ -3,7 +3,7 @@ use std::{
     path::{Path, PathBuf},
     sync::{
         atomic::{AtomicBool, Ordering},
-        mpsc::{self, TryRecvError},
+        mpsc::{self, RecvError, TryRecvError},
         Arc,
     },
 };
@@ -94,19 +94,33 @@ impl Emulator {
         let mut eye_contents = vec![0u8; 384 * 224 * 2];
         let mut audio_samples = vec![];
         loop {
+            let mut idle = true;
             if self.running.load(Ordering::Acquire) {
+                idle = false;
                 self.sim.emulate_frame();
             }
             if let Some(renderer) = &mut self.renderer {
                 if self.sim.read_pixels(&mut eye_contents) {
+                    idle = false;
                     renderer.render(&eye_contents);
                 }
             }
             self.sim.read_samples(&mut audio_samples);
             if !audio_samples.is_empty() {
+                idle = false;
                 self.audio.update(&audio_samples);
                 audio_samples.clear();
             }
+            if idle {
+                // The game is paused, and we have output all the video/audio we have.
+                // Block the thread until a new command comes in.
+                match self.commands.recv() {
+                    Ok(command) => self.handle_command(command),
+                    Err(RecvError) => {
+                        return;
+                    }
+                }
+            }
             loop {
                 match self.commands.try_recv() {
                     Ok(command) => self.handle_command(command),

src/main.rs

@@ -1,9 +1,10 @@
-use std::{path::PathBuf, process, thread};
+use std::{path::PathBuf, process};
 
 use anyhow::Result;
 use app::App;
 use clap::Parser;
 use emulator::EmulatorBuilder;
+use thread_priority::{ThreadBuilder, ThreadPriority};
 use winit::event_loop::{ControlFlow, EventLoop};
 
 mod app;
@@ -26,16 +27,20 @@ fn main() -> Result<()> {
     if let Some(path) = args.rom {
         builder = builder.with_rom(&path);
     }
-    thread::spawn(move || {
+
-        let mut emulator = match builder.build() {
+    ThreadBuilder::default()
-            Ok(e) => e,
+        .name("Emulator".to_owned())
-            Err(err) => {
+        .priority(ThreadPriority::Max)
-                eprintln!("Error initializing emulator: {err}");
+        .spawn_careless(move || {
-                process::exit(1);
+            let mut emulator = match builder.build() {
-            }
+                Ok(e) => e,
-        };
+                Err(err) => {
-        emulator.run();
+                    eprintln!("Error initializing emulator: {err}");
-    });
+                    process::exit(1);
+                }
+            };
+            emulator.run();
+        })?;
 
     let event_loop = EventLoop::with_user_event().build().unwrap();
     event_loop.set_control_flow(ControlFlow::Poll);