diff --git a/crates/ptth_file_server_bin/src/main.rs b/crates/ptth_file_server_bin/src/main.rs
index a5c5554..9ae3f47 100644
--- a/crates/ptth_file_server_bin/src/main.rs
+++ b/crates/ptth_file_server_bin/src/main.rs
@@ -97,7 +97,7 @@ async fn main () -> Result <(), anyhow::Error> {
 		config_file.name.unwrap_or_else (|| "PTTH File Server".to_string ())
 	);
 	
-	let metrics_gauges = Arc::new (ArcSwap::from_pointee (None));
+	let metrics_gauges = Arc::new (ArcSwap::default ());
 	
 	let gauge_writer = Arc::clone (&metrics_gauges);
 	
diff --git a/crates/ptth_server/src/file_server/metrics.rs b/crates/ptth_server/src/file_server/metrics.rs
index 659f4e3..f5666f1 100644
--- a/crates/ptth_server/src/file_server/metrics.rs
+++ b/crates/ptth_server/src/file_server/metrics.rs
@@ -33,24 +33,57 @@ pub struct Startup {
 	pub startup_utc: DateTime <Utc>,
 }
 
+// Gauges are things we instananeously measure on a fixed interval.
+// They are not read back and accumulated like counters.
+
 #[derive (Debug, serde::Serialize)]
 pub struct Gauges {
 	pub utc: DateTime <Utc>,
 	pub rss_mib: u64,
+	
+	// What's the difference?
+	pub cpu_time_user: f64,
+	pub cpu_time_system: f64,
+	
+	#[serde (skip)]
+	pub cpu_usage: heim::process::CpuUsage,
 }
 
 impl Gauges {
 	pub async fn new () -> Result <Self, super::FileServerError> {
+		use tokio::join;
 		use heim::process;
-		use uom::si::information::mebibyte;
+		use uom::si::{
+			information::mebibyte,
+			ratio,
+			time::second,
+		};
 		
 		let our_process = process::current ().await?;
+		
+		let cpu_time = our_process.cpu_time ();
+		let cpu_usage = our_process.cpu_usage ();
+		
+		let (cpu_time, cpu_usage) = join! (
+			cpu_time,
+			cpu_usage,
+		);
+		
+		let cpu_time = cpu_time?;
+		
+		let cpu_time_user = cpu_time.user ().get::<second> ();
+		let cpu_time_system = cpu_time.system ().get::<second> ();
+		let cpu_usage = cpu_usage?;
+		
 		let mem = our_process.memory ().await?;
 		let rss_mib = mem.rss ().get::<mebibyte> ();
 		
 		let x = Gauges {
 			utc: Utc::now (),
 			rss_mib,
+			cpu_time_user,
+			cpu_time_system,
+			cpu_usage,
 		};
 		
 		debug! ("metric gauges: {:?}", x);
diff --git a/crates/ptth_server/src/lib.rs b/crates/ptth_server/src/lib.rs
index 81e619b..56eac6b 100644
--- a/crates/ptth_server/src/lib.rs
+++ b/crates/ptth_server/src/lib.rs
@@ -201,7 +201,7 @@ pub async fn run_server (
 	let handlebars = file_server::load_templates (&asset_root)?;
 	
 	let metrics_startup = file_server::metrics::Startup::new (config_file.name);
-	let metrics_gauges = Arc::new (ArcSwap::from_pointee (None));
+	let metrics_gauges = Arc::new (ArcSwap::default ());
 	
 	let state = Arc::new (State {
 		file_server: file_server::State {