Exclude L2 cache clear time from timing measurement (#527)

Author: yf225

tritonbench/components/do_bench/run.py

@@ -205,18 +205,40 @@ def _do_bench_cudagraph_with_cache_clear(
                 fn()
         torch.cuda.synchronize()
 
-        ret = []
+        cache_clear_graph = torch.cuda.CUDAGraph()
+        with torch.cuda.graph(cache_clear_graph):
+            for _ in range(n_repeat):
+                cache.zero_()
+        torch.cuda.synchronize()
+
         n_retries = 10
+        cache_clear_times = []
+        total_times = []
         for _ in range(n_retries):
+            cache_clear_start_event = torch.cuda.Event(enable_timing=True)
+            cache_clear_end_event = torch.cuda.Event(enable_timing=True)
+            cache_clear_start_event.record()
+            cache_clear_graph.replay()
+            cache_clear_end_event.record()
+            torch.cuda.synchronize()
+            cache_clear_times.append(
+                cache_clear_start_event.elapsed_time(cache_clear_end_event) / n_repeat
+            )
+
             start_event = torch.cuda.Event(enable_timing=True)
             end_event = torch.cuda.Event(enable_timing=True)
             start_event.record()
             g.replay()
             end_event.record()
             torch.cuda.synchronize()
-            ret.append(start_event.elapsed_time(end_event) / n_repeat)
+            total_times.append(start_event.elapsed_time(end_event) / n_repeat)
 
-    times = torch.tensor(ret, dtype=torch.float)
+    all_kernel_times = []
+    for total_time, cache_clear_time in zip(total_times, cache_clear_times):
+        kernel_time = total_time - cache_clear_time
+        all_kernel_times.append(kernel_time)
+
+    times = torch.tensor(all_kernel_times, dtype=torch.float)
     return _summarize_statistics(times, quantiles, return_mode)