From 23dc6e12f79411a56d7e2f43c222db9f7d4aebc9 Mon Sep 17 00:00:00 2001
From: David Schneller <david.schneller@tum.de>
Date: Mon, 30 Mar 2026 02:54:08 +0200
Subject: [PATCH] feat: switch to coarse-grained managed HIP allocations by
 default

---
 interfaces/hip/Memory.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/interfaces/hip/Memory.cpp b/interfaces/hip/Memory.cpp
index 6fff772..b4ef78a 100644
--- a/interfaces/hip/Memory.cpp
+++ b/interfaces/hip/Memory.cpp
@@ -26,11 +26,16 @@ void* ConcreteAPI::allocUnifiedMem(size_t size, bool compress, Destination hint)
   isFlagSet<DeviceSelected>(status);
   void* devPtr;
   APIWRAP(hipMallocManaged(&devPtr, size, hipMemAttachGlobal));
+
+  // make coarse-grained memory access behavior the default (match with allocGlobMem)
+  APIWRAP(hipMemAdvise(devPtr, size, hipMemAdviseSetCoarseGrain, 1));
+
   if (hint == Destination::Host) {
     APIWRAP(hipMemAdvise(devPtr, size, hipMemAdviseSetPreferredLocation, hipCpuDeviceId));
   } else {
     APIWRAP(hipMemAdvise(devPtr, size, hipMemAdviseSetPreferredLocation, getDeviceId()));
   }
+
   statistics.allocatedMemBytes += size;
   statistics.allocatedUnifiedMemBytes += size;
   memToSizeMap[devPtr] = size;