From f7e607eae4a15f9a19d82d69b770f63742e50a9c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20B=C3=BCrger?= <simon.buerger@rwth-aachen.de>
Date: Thu, 9 May 2024 23:33:04 +0100
Subject: [PATCH] proper warmup loop for latency

---
 Grid/Benchmark_Grid.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Grid/Benchmark_Grid.cpp b/Grid/Benchmark_Grid.cpp
index 8b81863..d8b8de9 100644
--- a/Grid/Benchmark_Grid.cpp
+++ b/Grid/Benchmark_Grid.cpp
@@ -266,7 +266,8 @@ class Benchmark
 
   static void Latency(void)
   {
-    int Nloop = 200;
+    int Nwarmup = 100;
+    int Nloop = 1000;
 
     Coordinate simd_layout = GridDefaultSimd(Nd, vComplexD::Nsimd());
     Coordinate mpi_layout = GridDefaultMpi();
@@ -302,7 +303,7 @@ class Benchmark
         time_statistics timestat;
         MPI_Status status;
 
-        for (int i = 0; i < Nloop; ++i)
+        for (int i = -Nwarmup; i < Nloop; ++i)
         {
           double start = usecond();
           if (from == me)
@@ -321,7 +322,8 @@ class Benchmark
             assert(err == MPI_SUCCESS);
           }
           double stop = usecond();
-          t_time[i] = stop - start;
+          if (i >= 0)
+            t_time[i] = stop - start;
         }
         // important: only the 'from' rank has a trustworthy time
         MPI_Bcast(t_time.data(), Nloop, MPI_DOUBLE, from, Grid.communicator);