perf: avoid sysinfo System::new_all() when only one metric is needed

crates/oxo-flow-core/src/config.rs

@@ -1267,7 +1267,10 @@ impl WorkflowConfig {
         let system_threads = num_cpus::get() as u32;
         let system_memory_mb = {
             use sysinfo::System;
-            let mut sys = System::new_all();
+            // Only memory is needed here; `System::new_all()` would walk all of
+            // /proc (every process, disk, and network interface) just to read
+            // total RAM, adding ~50ms to every parse/validate/dry-run/run call.
+            let mut sys = System::new();
             sys.refresh_memory();
             sys.total_memory() / 1024 / 1024
         };

crates/oxo-flow-core/src/executor/mod.rs

@@ -17,13 +17,15 @@ mod tests;
 /// Get available CPU threads for auto-scaling.
 #[must_use]
 pub fn available_threads() -> u32 {
-    System::new_all().cpus().len() as u32
+    num_cpus::get() as u32
 }
 
 /// Get available memory in GB for auto-scaling.
 #[must_use]
 pub fn available_memory_gb() -> u64 {
-    let mut sys = System::new_all();
+    // Only memory is needed; `System::new_all()` would also walk every process,
+    // disk, and network interface in /proc for no reason.
+    let mut sys = System::new();
     sys.refresh_memory();
     sys.available_memory() / (1024 * 1024 * 1024) // Convert bytes to GB
 }

crates/oxo-flow-core/src/executor/process.rs

@@ -300,7 +300,8 @@ fn detect_total_memory_mb() -> u64 {
     // Primary: sysinfo crate (cross-platform)
     if let Ok(mb) = std::panic::catch_unwind(|| {
         use sysinfo::System;
-        let mut sys = System::new_all();
+        // Only memory is needed; avoid `System::new_all()` scanning all of /proc.
+        let mut sys = System::new();
         sys.refresh_memory();
         sys.total_memory() / 1024 / 1024
     }) && mb > 0