Update validation script first batch prime and clear cuda cache between multi-model runs

Author: rwightman

validate.py

@@ -145,7 +145,8 @@ def validate(args):
     model.eval()
     with torch.no_grad():
         # warmup, reduce variability of first batch time, especially for comparing torchscript vs non
-        model(torch.randn((args.batch_size,) + data_config['input_size']).cuda())
+        input = torch.randn((args.batch_size,) + data_config['input_size']).cuda()
+        model(input)
         end = time.time()
         for i, (input, target) in enumerate(loader):
             if args.no_prefetcher:
@@ -238,6 +239,7 @@ def main():
                             raise e
                         batch_size = max(batch_size // 2, args.num_gpu)
                         print("Validation failed, reducing batch size by 50%")
+                        torch.cuda.empty_cache()
                 result.update(r)
                 if args.checkpoint:
                     result['checkpoint'] = args.checkpoint