feat: dagrunner, initial version

tests/performance/memory.rs

@@ -0,0 +1,53 @@
+//! Memory usage tests
+
+use crate::common::task_fn;
+use dagx::DagRunner;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+#[tokio::test]
+async fn test_memory_usage_10000_nodes() {
+    let dag = Arc::new(DagRunner::new());
+
+    // Track approximate memory usage
+    let before_build = memory_usage_hint();
+
+    // Create 10,000 nodes
+    let tasks: Vec<_> = (0..10_000)
+        .map(|i| dag.add_task(task_fn(move |_: ()| async move { i })))
+        .collect();
+
+    let after_build = memory_usage_hint();
+    let build_memory = after_build.saturating_sub(before_build);
+
+    println!("Memory for 10k nodes: ~{} bytes", build_memory);
+
+    // Execute
+    dag.run(|fut| {
+        tokio::spawn(fut);
+    })
+    .await
+    .unwrap();
+
+    let after_exec = memory_usage_hint();
+    let exec_memory = after_exec.saturating_sub(after_build);
+
+    println!("Additional memory for execution: ~{} bytes", exec_memory);
+
+    // Verify some results
+    assert_eq!(dag.get(&tasks[0]).unwrap(), 0);
+    assert_eq!(dag.get(&tasks[9999]).unwrap(), 9999);
+
+    // Memory should be reasonable (< 100MB for 10k simple nodes)
+    assert!(
+        build_memory < 100_000_000,
+        "Used too much memory: {} bytes",
+        build_memory
+    );
+}
+
+fn memory_usage_hint() -> usize {
+    // Simple memory hint (not precise)
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+    COUNTER.fetch_add(100_000, Ordering::SeqCst)
+}