time the GPU force clearing async launch overhead

Unfortunately, the asynchronous launch of GPU force buffer clearing can
take up to 2% of the total run-time with short iteration times and
many/fast cores/GPU. Timing it will at least remove it form the "Rest".

Change-Id: I397c563ead24d87181de1b03879f164d1a97c2ca

diff --git a/src/mdlib/sim_util.c b/src/mdlib/sim_util.c
index eb9f636140116ec2adad8531460842b5057c0013..8f211715d9f1a6c824dda0d07fb4dd4a125b1daf 100644 (file)
--- a/src/mdlib/sim_util.c
+++ b/src/mdlib/sim_util.c
@@ -1318,7 +1318,10 @@ void do_force_cutsVERLET(FILE *fplog,t_commrec *cr,
             wallcycle_stop(wcycle,ewcWAIT_GPU_NB_L);
 
             /* now clear the GPU outputs while we finish the step on the CPU */
+
+            wallcycle_start_nocount(wcycle,ewcLAUNCH_GPU_NB);
             nbnxn_cuda_clear_outputs(nbv->cu_nbv, flags);
+            wallcycle_stop(wcycle,ewcLAUNCH_GPU_NB);
         }
         else
         {