Memory allocation improvements for metrics collector .

src/utils/fordebug.rs

@@ -0,0 +1,31 @@
+use std::alloc::{GlobalAlloc, Layout, System};
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+pub struct CountingAllocator;
+
+pub static ALLOC_COUNT: AtomicUsize = AtomicUsize::new(0);
+pub static DEALLOC_COUNT: AtomicUsize = AtomicUsize::new(0);
+pub static ALLOC_BYTES: AtomicUsize = AtomicUsize::new(0);
+#[allow(dead_code)]
+unsafe impl GlobalAlloc for CountingAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        ALLOC_COUNT.fetch_add(1, Ordering::Relaxed);
+        ALLOC_BYTES.fetch_add(layout.size(), Ordering::Relaxed);
+        System.alloc(layout)
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        DEALLOC_COUNT.fetch_add(1, Ordering::Relaxed);
+        System.dealloc(ptr, layout)
+    }
+}
+
+// Uncomment following lines and comment allocator in main.rs
+// #[global_allocator]
+// pub static A: CountingAllocator = CountingAllocator;
+#[allow(dead_code)]
+fn for_example() {
+    let before = crate::utils::fordebug::ALLOC_COUNT.load(Ordering::Relaxed);
+    let after = crate::utils::fordebug::ALLOC_COUNT.load(Ordering::Relaxed);
+    println!("Allocations : {}", after - before);
+}