From a963406f7c0bb6e8c7fecd35605f8f812b8d6850 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Constantin=20F=C3=BCrst?= <c@fuersten.info>
Date: Tue, 30 Jan 2024 15:04:53 +0100
Subject: [PATCH] move mode selection to Configuration.hpp, adapt the
 CopyMethodPolicy-Function to return only src_node for task sizes under 16MiB
 which is now required to not cause high submission count which slows down
 small copies

---
 qdp_project/src/Benchmark.cpp              |  4 ----
 qdp_project/src/Configuration.hpp          |  6 ++++++
 qdp_project/src/utils/BenchmarkHelpers.cpp | 10 ++++++++++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/qdp_project/src/Benchmark.cpp b/qdp_project/src/Benchmark.cpp
index 98d05b7..de2de99 100644
--- a/qdp_project/src/Benchmark.cpp
+++ b/qdp_project/src/Benchmark.cpp
@@ -14,10 +14,6 @@
 
 #include "../../offloading-cacher/cache.hpp"
 
-#ifndef MODE_SET_BY_CMAKE
-#define MODE_SIMPLE_PREFETCH
-#endif
-
 #include "Configuration.hpp"
 #include "BenchmarkHelpers.cpp"
 
diff --git a/qdp_project/src/Configuration.hpp b/qdp_project/src/Configuration.hpp
index 990fccf..7462cf1 100644
--- a/qdp_project/src/Configuration.hpp
+++ b/qdp_project/src/Configuration.hpp
@@ -1,5 +1,11 @@
 #pragma once
 
+#include "utils/memory_literals.h"
+
+#ifndef MODE_SET_BY_CMAKE
+#define MODE_SIMPLE_PREFETCH
+#endif
+
 constexpr size_t WL_SIZE_B = 4_GiB;
 constexpr uint32_t WARMUP_ITERATION_COUNT = 5;
 constexpr uint32_t ITERATION_COUNT = 5;
diff --git a/qdp_project/src/utils/BenchmarkHelpers.cpp b/qdp_project/src/utils/BenchmarkHelpers.cpp
index 00727f5..4d000c7 100644
--- a/qdp_project/src/utils/BenchmarkHelpers.cpp
+++ b/qdp_project/src/utils/BenchmarkHelpers.cpp
@@ -2,6 +2,8 @@
 
 #include "../Configuration.hpp"
 
+#include "memory_literals.h"
+
 constexpr size_t SCANA_TIMING_INDEX = 0;
 constexpr size_t SCANB_TIMING_INDEX = 1;
 constexpr size_t AGGRJ_TIMING_INDEX = 2;
@@ -38,6 +40,14 @@ int CachePlacementPolicy(const int numa_dst_node, const int numa_src_node, const
 }
 
 std::vector<int> CopyMethodPolicy(const int numa_dst_node, const int numa_src_node, const size_t data_size) {
+    // for small data it is more efficient to run on only one node
+    // which causes less submissions and therefore completes faster
+    // as submission cost matters for low transfer size
+
+    if (data_size < 16_MiB) {
+        return std::vector<int>{ (numa_src_node >= 8 ? numa_src_node - 8 : numa_src_node) };
+    }
+
     // for sufficiently large data, smart copy is used which will utilize
     // all four engines for intra-socket copy operations and cross copy on
     // the source and destination nodes for inter-socket copy