optimizations at high entity counts

2 files changed, 71 insertions, 0 deletions

diff --git a/azalea/examples/testbot/main.rs b/azalea/examples/testbot/main.rs
index c74dcee7..63d83c8a 100644
--- a/azalea/examples/testbot/main.rs
+++ b/azalea/examples/testbot/main.rs
@@ -24,6 +24,7 @@
 
 mod commands;
 pub mod killaura;
+pub mod mspt;
 
 use std::{env, process, sync::Arc, thread, time::Duration};
 
@@ -75,6 +76,7 @@ async fn main() -> AppExit {
             args,
             commands: Arc::new(commands),
         })
+        // .add_plugins(mspt::MsptPlugin)
         .start(join_address)
         .await
 }
diff --git a/azalea/examples/testbot/mspt.rs b/azalea/examples/testbot/mspt.rs
new file mode 100644
index 00000000..b4931d71
--- /dev/null
+++ b/azalea/examples/testbot/mspt.rs
@@ -0,0 +1,69 @@
+//! A debugging plugin that logs the duration of ECS `Update`s every tick.
+
+use std::time::{Duration, Instant};
+
+use azalea::prelude::Resource;
+use bevy_app::Plugin;
+use bevy_ecs::{schedule::IntoScheduleConfigs, system::ResMut};
+
+pub struct MsptPlugin;
+impl Plugin for MsptPlugin {
+    fn build(&self, app: &mut bevy_app::App) {
+        app.insert_resource(MsptData {
+            last_log_time: Instant::now(),
+            this_update_start_time: Instant::now(),
+            update_times: Vec::new(),
+        })
+        .add_systems(bevy_app::PreUpdate, on_update_start)
+        .add_systems(
+            bevy_app::PostUpdate,
+            (on_update_end, log_mspt_stats).chain(),
+        );
+    }
+}
+
+#[derive(Resource)]
+struct MsptData {
+    this_update_start_time: Instant,
+    last_log_time: Instant,
+
+    update_times: Vec<Duration>,
+}
+fn log_mspt_stats(mut stats: ResMut<MsptData>) {
+    if stats.last_log_time.elapsed() < Duration::from_secs(1) {
+        return;
+    }
+    stats.last_log_time = Instant::now();
+
+    let mut fastest_update_duration = None;
+    let mut summed_update_durations = Duration::ZERO;
+    let mut num_updates = 0;
+    for update in stats.update_times.drain(..) {
+        summed_update_durations += update;
+        num_updates += 1;
+        let Some(fastest_update) = &mut fastest_update_duration else {
+            fastest_update_duration = Some(update);
+            continue;
+        };
+        if update < *fastest_update {
+            *fastest_update = update;
+        }
+    }
+
+    if num_updates > 0
+        && let Some(fastest_update_duration) = fastest_update_duration
+    {
+        let avg_update_duration = summed_update_durations / num_updates;
+
+        println!();
+        println!("Average update duration: {avg_update_duration:?}");
+        println!("Fastest update duration: {fastest_update_duration:?}");
+    }
+}
+fn on_update_start(mut data: ResMut<MsptData>) {
+    data.this_update_start_time = Instant::now();
+}
+fn on_update_end(mut data: ResMut<MsptData>) {
+    let elapsed = data.this_update_start_time.elapsed();
+    data.update_times.push(elapsed);
+}