code optimizations to reduce cpu usage of agent on all platforms and additional unit test.

Cargo.lock

@@ -158,7 +158,7 @@ dependencies = [
  "sha1",
  "sync_wrapper",
  "tokio",
- "tokio-tungstenite",
+ "tokio-tungstenite 0.24.0",
  "tower 0.5.2",
  "tower-layer",
  "tower-service",
@@ -2181,13 +2181,13 @@ dependencies = [
  "sysinfo",
  "tempfile",
  "tokio",
- "tokio-tungstenite",
+ "tokio-tungstenite 0.24.0",
  "url",
 ]
 
 [[package]]
 name = "socktop_agent"
-version = "1.40.66"
+version = "1.40.67"
 dependencies = [
  "anyhow",
  "assert_cmd",
@@ -2210,6 +2210,7 @@ dependencies = [
  "tempfile",
  "time",
  "tokio",
+ "tokio-tungstenite 0.21.0",
  "tonic-build",
  "tracing",
  "tracing-subscriber",
@@ -2463,6 +2464,18 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "tokio-tungstenite"
+version = "0.21.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c83b561d025642014097b66e6c1bb422783339e0909e4429cde4749d1990bc38"
+dependencies = [
+ "futures-util",
+ "log",
+ "tokio",
+ "tungstenite 0.21.0",
+]
+
 [[package]]
 name = "tokio-tungstenite"
 version = "0.24.0"
@@ -2475,7 +2488,7 @@ dependencies = [
  "rustls-pki-types",
  "tokio",
  "tokio-rustls 0.26.2",
- "tungstenite",
+ "tungstenite 0.24.0",
 ]
 
 [[package]]
@@ -2608,6 +2621,25 @@ dependencies = [
  "tracing-log",
 ]
 
+[[package]]
+name = "tungstenite"
+version = "0.21.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ef1a641ea34f399a848dea702823bbecfb4c486f911735368f1f137cb8257e1"
+dependencies = [
+ "byteorder",
+ "bytes",
+ "data-encoding",
+ "http",
+ "httparse",
+ "log",
+ "rand",
+ "sha1",
+ "thiserror 1.0.69",
+ "url",
+ "utf-8",
+]
+
 [[package]]
 name = "tungstenite"
 version = "0.24.0"

socktop_agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "socktop_agent"
-version = "1.40.66"
+version = "1.40.67"
 authors = ["Jason Witty <jasonpwitty+socktop@proton.me>"]
 description = "Remote system monitor over WebSocket, TUI like top"
 edition = "2021"
@@ -36,3 +36,4 @@ protoc-bin-vendored = "3"
 [dev-dependencies]
 assert_cmd = "2.0"
 tempfile = "3.10"
+tokio-tungstenite = "0.21"

socktop_agent/src/metrics.rs

@@ -49,6 +49,15 @@ struct GpuCache {
 }
 static GPUC: OnceCell<Mutex<GpuCache>> = OnceCell::new();
 
+// Static caches for unchanging data
+static HOSTNAME: OnceCell<String> = OnceCell::new();
+struct NetworkNameCache {
+    names: Vec<String>,
+    infos: Vec<NetworkInfo>,
+}
+static NETWORK_CACHE: OnceCell<Mutex<NetworkNameCache>> = OnceCell::new();
+static CPU_VEC: OnceCell<Mutex<Vec<f32>>> = OnceCell::new();
+
 fn cached_temp() -> Option<f32> {
     if !temp_enabled() {
         return None;
@@ -121,9 +130,19 @@ pub async fn collect_fast_metrics(state: &AppState) -> Metrics {
         warn!("sysinfo selective refresh panicked: {e:?}");
     }
 
-    let hostname = state.hostname.clone();
+    // Get or initialize hostname once
+    let hostname = HOSTNAME.get_or_init(|| state.hostname.clone()).clone();
+
+    // Reuse CPU vector to avoid allocation
     let cpu_total = sys.global_cpu_usage();
-    let cpu_per_core: Vec<f32> = sys.cpus().iter().map(|c| c.cpu_usage()).collect();
+    let cpu_per_core = {
+        let vec_lock = CPU_VEC.get_or_init(|| Mutex::new(Vec::with_capacity(32)));
+        let mut vec = vec_lock.lock().unwrap();
+        vec.clear();
+        vec.extend(sys.cpus().iter().map(|c| c.cpu_usage()));
+        vec.clone() // Still need to clone but the allocation is reused
+    };
+
     let mem_total = sys.total_memory();
     let mem_used = mem_total.saturating_sub(sys.available_memory());
     let swap_total = sys.total_swap();
@@ -156,17 +175,38 @@ pub async fn collect_fast_metrics(state: &AppState) -> Metrics {
         None
     };
 
-    // Networks
+    // Networks with reusable name cache
-    let networks: Vec<NetworkInfo> = {
+    let networks = {
         let mut nets = state.networks.lock().await;
         nets.refresh(false);
-        nets.iter()
+
-            .map(|(name, data)| NetworkInfo {
+        // Get or initialize network cache
-                name: name.to_string(),
+        let cache = NETWORK_CACHE.get_or_init(|| {
+            Mutex::new(NetworkNameCache {
+                names: Vec::new(),
+                infos: Vec::with_capacity(4), // Most systems have few network interfaces
+            })
+        });
+        let mut cache = cache.lock().unwrap();
+
+        // Collect current network names
+        let current_names: Vec<_> = nets.keys().map(|name| name.to_string()).collect();
+
+        // Update cached network names if they changed
+        if cache.names != current_names {
+            cache.names = current_names;
+        }
+
+        // Reuse NetworkInfo objects
+        cache.infos.clear();
+        for (name, data) in nets.iter() {
+            cache.infos.push(NetworkInfo {
+                name: name.to_string(), // We'll still clone but avoid Vec reallocation
                 received: data.total_received(),
                 transmitted: data.total_transmitted(),
-            })
+            });
-            .collect()
+        }
+        cache.infos.clone()
     };
 
     // GPUs: if we already determined none exist, short-circuit (no repeated probing)

socktop_agent/src/ws.rs

@@ -7,13 +7,33 @@ use axum::{
 };
 use flate2::{write::GzEncoder, Compression};
 use futures_util::StreamExt;
+use once_cell::sync::OnceCell;
 use std::collections::HashMap;
 use std::io::Write;
+use tokio::sync::Mutex;
 
 use crate::metrics::{collect_disks, collect_fast_metrics, collect_processes_all};
 use crate::proto::pb;
 use crate::state::AppState;
 
+// Compression threshold based on typical payload size
+const COMPRESSION_THRESHOLD: usize = 768;
+
+// Reusable buffer for compression to avoid allocations
+struct CompressionCache {
+    processes_vec: Vec<pb::Process>,
+}
+
+impl CompressionCache {
+    fn new() -> Self {
+        Self {
+            processes_vec: Vec::with_capacity(512), // Typical process count
+        }
+    }
+}
+
+static COMPRESSION_CACHE: OnceCell<Mutex<CompressionCache>> = OnceCell::new();
+
 pub async fn ws_handler(
     ws: WebSocketUpgrade,
     State(state): State<AppState>,
@@ -46,39 +66,51 @@ async fn handle_socket(mut socket: WebSocket, state: AppState) {
             }
             Message::Text(ref text) if text == "get_processes" => {
                 let payload = collect_processes_all(&state).await;
+
                 // Map to protobuf message
-                let rows: Vec<pb::Process> = payload
+                // Get cached buffers
-                    .top_processes
+                let cache = COMPRESSION_CACHE.get_or_init(|| Mutex::new(CompressionCache::new()));
-                    .into_iter()
+                let mut cache = cache.lock().await;
-                    .map(|p| pb::Process {
+
+                // Reuse process vector to build the list
+                cache.processes_vec.clear();
+                cache
+                    .processes_vec
+                    .extend(payload.top_processes.into_iter().map(|p| pb::Process {
                         pid: p.pid,
                         name: p.name,
                         cpu_usage: p.cpu_usage,
                         mem_bytes: p.mem_bytes,
-                    })
+                    }));
-                    .collect();
+
                 let pb = pb::Processes {
                     process_count: payload.process_count as u64,
-                    rows,
+                    rows: std::mem::take(&mut cache.processes_vec),
                 };
+
                 let mut buf = Vec::with_capacity(8 * 1024);
                 if prost::Message::encode(&pb, &mut buf).is_err() {
                     let _ = socket.send(Message::Close(None)).await;
                 } else {
                     // compress if large
-                    if buf.len() <= 768 {
+                    if buf.len() <= COMPRESSION_THRESHOLD {
                         let _ = socket.send(Message::Binary(buf)).await;
                     } else {
-                        let mut enc = GzEncoder::new(Vec::new(), Compression::fast());
+                        // Create a new encoder for each message to ensure proper gzip headers
-                        if enc.write_all(&buf).is_ok() {
+                        let mut encoder =
-                            let bin = enc.finish().unwrap_or(buf);
+                            GzEncoder::new(Vec::with_capacity(buf.len()), Compression::fast());
-                            let _ = socket.send(Message::Binary(bin)).await;
+                        match encoder.write_all(&buf).and_then(|_| encoder.finish()) {
-                        } else {
+                            Ok(compressed) => {
+                                let _ = socket.send(Message::Binary(compressed)).await;
+                            }
+                            Err(_) => {
                                 let _ = socket.send(Message::Binary(buf)).await;
                             }
                         }
                     }
                 }
+                drop(cache); // Explicit drop to release mutex early
+            }
             Message::Close(_) => break,
             _ => {}
         }
@@ -91,7 +123,7 @@ async fn handle_socket(mut socket: WebSocket, state: AppState) {
 // Small, cheap gzip for larger payloads; send text for small.
 async fn send_json<T: serde::Serialize>(ws: &mut WebSocket, value: &T) -> Result<(), axum::Error> {
     let json = serde_json::to_string(value).expect("serialize");
-    if json.len() <= 768 {
+    if json.len() <= COMPRESSION_THRESHOLD {
         return ws.send(Message::Text(json)).await;
     }
     let mut enc = GzEncoder::new(Vec::new(), Compression::fast());
@@ -99,3 +131,83 @@ async fn send_json<T: serde::Serialize>(ws: &mut WebSocket, value: &T) -> Result
     let bin = enc.finish().unwrap_or_else(|_| json.into_bytes());
     ws.send(Message::Binary(bin)).await
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use prost::Message as ProstMessage;
+    use sysinfo::System;
+
+    #[tokio::test]
+    async fn test_process_list_not_empty() {
+        // Initialize system data first to ensure we have processes
+        let mut sys = System::new_all();
+        sys.refresh_all();
+
+        // Create state and put the refreshed system in it
+        let state = AppState::new();
+        {
+            let mut sys_lock = state.sys.lock().await;
+            *sys_lock = sys;
+        }
+
+        // Get processes directly using the collection function
+        let processes = collect_processes_all(&state).await;
+
+        // Convert to protobuf message format
+        let cache = COMPRESSION_CACHE.get_or_init(|| Mutex::new(CompressionCache::new()));
+        let mut cache = cache.lock().await;
+
+        // Reuse process vector to build the list
+        cache.processes_vec.clear();
+        cache
+            .processes_vec
+            .extend(processes.top_processes.into_iter().map(|p| pb::Process {
+                pid: p.pid,
+                name: p.name,
+                cpu_usage: p.cpu_usage,
+                mem_bytes: p.mem_bytes,
+            }));
+
+        // Create the protobuf message
+        let pb = pb::Processes {
+            process_count: processes.process_count as u64,
+            rows: cache.processes_vec.clone(),
+        };
+
+        // Test protobuf encoding/decoding
+        let mut buf = Vec::new();
+        prost::Message::encode(&pb, &mut buf).expect("Failed to encode protobuf");
+        let decoded = pb::Processes::decode(buf.as_slice()).expect("Failed to decode protobuf");
+
+        // Print debug info
+        println!("Process count: {}", pb.process_count);
+        println!("Process vector length: {}", pb.rows.len());
+        println!("Encoded size: {} bytes", buf.len());
+        println!("Decoded process count: {}", decoded.rows.len());
+
+        // Print first few processes if available
+        for (i, process) in pb.rows.iter().take(5).enumerate() {
+            println!(
+                "Process {}: {} (PID: {}) CPU: {:.1}% MEM: {} bytes",
+                i + 1,
+                process.name,
+                process.pid,
+                process.cpu_usage,
+                process.mem_bytes
+            );
+        }
+
+        // Validate
+        assert!(!pb.rows.is_empty(), "Process list should not be empty");
+        assert!(
+            pb.process_count > 0,
+            "Process count should be greater than 0"
+        );
+        assert_eq!(
+            pb.process_count as usize,
+            pb.rows.len(),
+            "Process count mismatch with actual rows"
+        );
+    }
+}