Please consider the following formatting changes to #14103

GPU/Common/GPUCommonAlgorithm.h

@@ -24,9 +24,7 @@
 
 // ----------------------------- SORTING -----------------------------
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 class GPUCommonAlgorithm
 {
@@ -43,6 +41,10 @@ class GPUCommonAlgorithm
   GPUd() static void sortInBlock(T* begin, T* end, const S& comp);
   template <class T, class S>
   GPUd() static void sortDeviceDynamic(T* begin, T* end, const S& comp);
+#ifndef __OPENCL__
+  template <class T, class S>
+  GPUh() static void sortOnDevice(auto* rec, int32_t stream, T* begin, size_t N, const S& comp);
+#endif
   template <class T>
   GPUd() static void swap(T& a, T& b);
 
@@ -71,13 +73,6 @@ class GPUCommonAlgorithm
   template <typename I>
   GPUd() static void IterSwap(I a, I b) noexcept;
 };
-} // namespace gpu
-} // namespace o2
-
-namespace o2
-{
-namespace gpu
-{
 
 #ifndef GPUCA_ALGORITHM_STD
 template <typename I>
@@ -217,18 +212,15 @@ GPUdi() void GPUCommonAlgorithm::QuickSort(I f, I l) noexcept
 
 typedef GPUCommonAlgorithm CAAlgo;
 
-} // namespace gpu
-} // namespace o2
+} // namespace o2::gpu
 
 #if (((defined(__CUDACC__) && !defined(__clang__)) || defined(__HIPCC__))) && !defined(GPUCA_GPUCODE_GENRTC) && !defined(GPUCA_GPUCODE_HOSTONLY)
 
 #include "GPUCommonAlgorithmThrust.h"
 
 #else
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 
 template <class T>
@@ -247,15 +239,12 @@ GPUdi() void GPUCommonAlgorithm::sortDeviceDynamic(T* begin, T* end, const S& co
   GPUCommonAlgorithm::sort(begin, end, comp);
 }
 
-} // namespace gpu
-} // namespace o2
+} // namespace o2::gpu
 
 #endif // THRUST
 // sort and sortInBlock below are not taken from Thrust, since our implementations are faster
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 
 template <class T>
@@ -328,8 +317,7 @@ GPUdi() void GPUCommonAlgorithm::swap(T& a, T& b)
 }
 #endif
 
-} // namespace gpu
-} // namespace o2
+} // namespace o2::gpu
 
 // ----------------------------- WORK GROUP FUNCTIONS -----------------------------
 
@@ -458,4 +446,8 @@ GPUdi() T warp_broadcast(T v, int32_t i)
 
 #endif
 
+#ifdef GPUCA_ALGORITHM_STD
+#undef GPUCA_ALGORITHM_STD
+#endif
+
 #endif

GPU/Common/GPUCommonAlgorithmThrust.h

@@ -23,16 +23,19 @@
 #pragma GCC diagnostic pop
 
 #include "GPUCommonDef.h"
+#include "GPUCommonHelpers.h"
 
-#ifdef __CUDACC__
+#ifndef __HIPCC__ // CUDA
 #define GPUCA_THRUST_NAMESPACE thrust::cuda
-#else
+#define GPUCA_CUB_NAMESPACE cub
+#include <cub/cub.cuh>
+#else // HIP
 #define GPUCA_THRUST_NAMESPACE thrust::hip
+#define GPUCA_CUB_NAMESPACE hipcub
+#include <hipcub/hipcub.hpp>
 #endif
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 
 // - Our quicksort and bubble sort implementations are faster
@@ -54,7 +57,7 @@ GPUdi() void GPUCommonAlgorithm::sort(T* begin, T* end, const S& comp)
 }
 
 template <class T>
-GPUdi() void GPUCommonAlgorithm::sortInBlock(T* begin, T* end)
+GPUdi() void GPUCommonAlgorithm::sortInBlock(T* begin, T* end) // TODO: Try cub::BlockMergeSort
 {
   if (get_local_id(0) == 0) {
     sortDeviceDynamic(begin, end);
@@ -87,7 +90,24 @@ GPUdi() void GPUCommonAlgorithm::sortDeviceDynamic(T* begin, T* end, const S& co
   thrust::sort(GPUCA_THRUST_NAMESPACE::par, thrustBegin, thrustEnd, comp);
 }
 
-} // namespace gpu
-} // namespace o2
+template <class T, class S>
+GPUhi() void GPUCommonAlgorithm::sortOnDevice(auto* rec, int32_t stream, T* begin, size_t N, const S& comp)
+{
+  thrust::device_ptr<T> p(begin);
+#if 0 // Use Thrust
+  auto alloc = rec->getThrustVolatileDeviceAllocator();
+  thrust::sort(GPUCA_THRUST_NAMESPACE::par(alloc).on(rec->mInternals->Streams[stream]), p, p + N, comp);
+#else // Use CUB
+  size_t tempSize = 0;
+  void* tempMem = nullptr;
+  GPUChkErrS(GPUCA_CUB_NAMESPACE::DeviceMergeSort::SortKeys(tempMem, tempSize, begin, N, comp, rec->mInternals->Streams[stream]));
+  tempMem = rec->AllocateVolatileDeviceMemory(tempSize);
+  GPUChkErrS(GPUCA_CUB_NAMESPACE::DeviceMergeSort::SortKeys(tempMem, tempSize, begin, N, comp, rec->mInternals->Streams[stream]));
+#endif
+}
+} // namespace o2::gpu
+
+#undef GPUCA_THRUST_NAMESPACE
+#undef GPUCA_CUB_NAMESPACE
 
 #endif

GPU/Common/GPUCommonHelpers.h

@@ -35,6 +35,7 @@
 #include "GPUCommonDef.h"
 #include "GPUCommonLogger.h"
 #include <cstdint>
+#include <functional>
 
 namespace o2::gpu::internal
 {
@@ -60,4 +61,22 @@ static inline int32_t GPUReconstructionChkErr(const int64_t error, const char* f
 #undef GPUCOMMON_INTERNAL_CAT
 } // namespace o2::gpu::internal
 
+namespace o2::gpu
+{
+class GPUReconstruction;
+class ThrustVolatileAllocator
+{
+ public:
+  typedef char value_type;
+
+  char* allocate(std::ptrdiff_t n);
+  void deallocate(char* ptr, size_t);
+
+ private:
+  ThrustVolatileAllocator(GPUReconstruction* r);
+  std::function<char*(size_t)> mAlloc;
+  friend class GPUReconstruction;
+};
+} // namespace o2::gpu
+
 #endif

GPU/Common/GPUCommonMath.h

@@ -42,9 +42,7 @@
     #define GPUCA_CHOICE(c1, c2, c3) (c1) // Select first option for Host
 #endif // clang-format on
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 
 class GPUCommonMath
@@ -540,7 +538,6 @@ GPUdii() void GPUCommonMath::AtomicMinInternal(GPUglobalref() GPUgeneric() GPUAt
 
 #undef GPUCA_CHOICE
 
-} // namespace gpu
-} // namespace o2
+} // namespace o2::gpu
 
 #endif // GPUCOMMONMATH_H

GPU/Common/GPUCommonTransform3D.h

@@ -17,9 +17,7 @@
 
 #include "GPUCommonDef.h"
 
-namespace o2
-{
-namespace gpu
+namespace o2::gpu
 {
 class Transform3D
 {
@@ -79,7 +77,6 @@ class Transform3D
                                 kZZ = 10,
                                 kDZ = 11 };
 };
-} // namespace gpu
-} // namespace o2
+} // namespace o2::gpu
 
 #endif

GPU/Common/GPUROOTCartesianFwd.h

@@ -46,9 +46,7 @@ class DefaultCoordinateSystemTag;
 } // namespace Math
 } // namespace ROOT
 
-namespace o2
-{
-namespace math_utils
+namespace o2::math_utils
 {
 
 namespace detail
@@ -79,7 +77,6 @@ template <typename T>
 using Vector3D = detail::GPUPoint3D<T, 1>;
 #endif
 
-} // namespace math_utils
-} // namespace o2
+} // namespace o2::math_utils
 
 #endif

GPU/Common/GPUROOTSMatrixFwd.h

@@ -35,9 +35,7 @@ class MatRepStd;
 } // namespace Math
 } // namespace ROOT
 
-namespace o2
-{
-namespace math_utils
+namespace o2::math_utils
 {
 
 namespace detail
@@ -72,7 +70,6 @@ template <class T, uint32_t D1, uint32_t D2 = D1>
 using MatRepStd = detail::MatRepStdGPU<T, D1, D2>;
 #endif
 
-} // namespace math_utils
-} // namespace o2
+} // namespace o2::math_utils
 
 #endif

GPU/GPUTracking/Base/GPUGeneralKernels.h

@@ -27,9 +27,9 @@
 #endif
 
 #if defined(__HIPCC__)
-#define GPUCA_CUB hipcub
+#define GPUCA_CUB_NAMESPACE hipcub
 #else
-#define GPUCA_CUB cub
+#define GPUCA_CUB_NAMESPACE cub
 #endif
 
 namespace o2::gpu
@@ -54,7 +54,7 @@ class GPUKernelTemplate
   struct GPUSharedMemoryWarpScan64 {
     // Provides the shared memory resources for warp wide CUB collectives
 #if (defined(__CUDACC__) || defined(__HIPCC__)) && defined(GPUCA_GPUCODE) && !defined(GPUCA_GPUCODE_HOSTONLY)
-    typedef GPUCA_CUB::WarpScan<T> WarpScan;
+    typedef GPUCA_CUB_NAMESPACE::WarpScan<T> WarpScan;
     union {
       typename WarpScan::TempStorage cubWarpTmpMem;
     };
@@ -65,9 +65,9 @@ class GPUKernelTemplate
   struct GPUSharedMemoryScan64 {
     // Provides the shared memory resources for CUB collectives
 #if (defined(__CUDACC__) || defined(__HIPCC__)) && defined(GPUCA_GPUCODE) && !defined(GPUCA_GPUCODE_HOSTONLY)
-    typedef GPUCA_CUB::BlockScan<T, I> BlockScan;
-    typedef GPUCA_CUB::BlockReduce<T, I> BlockReduce;
-    typedef GPUCA_CUB::WarpScan<T> WarpScan;
+    typedef GPUCA_CUB_NAMESPACE::BlockScan<T, I> BlockScan;
+    typedef GPUCA_CUB_NAMESPACE::BlockReduce<T, I> BlockReduce;
+    typedef GPUCA_CUB_NAMESPACE::WarpScan<T> WarpScan;
     union {
       typename BlockScan::TempStorage cubTmpMem;
       typename BlockReduce::TempStorage cubReduceTmpMem;
@@ -110,6 +110,6 @@ class GPUitoa : public GPUKernelTemplate
 
 } // namespace o2::gpu
 
-#undef GPUCA_CUB
+#undef GPUCA_CUB_NAMESPACE
 
 #endif

GPU/GPUTracking/Base/GPUReconstruction.cxx

@@ -30,6 +30,7 @@
 #include "GPUROOTDumpCore.h"
 #include "GPUConfigDump.h"
 #include "GPUChainTracking.h"
+#include "GPUCommonHelpers.h"
 
 #include "GPUMemoryResource.h"
 #include "GPUChain.h"
@@ -1193,3 +1194,12 @@ void GPUReconstruction::SetInputControl(void* ptr, size_t size)
 {
   mInputControl.set(ptr, size);
 }
+
+ThrustVolatileAllocator::ThrustVolatileAllocator(GPUReconstruction* r)
+{
+  mAlloc = [&r](size_t n) { return (char*)r->AllocateVolatileDeviceMemory(n); };
+}
+ThrustVolatileAllocator GPUReconstruction::getThrustVolatileDeviceAllocator()
+{
+  return ThrustVolatileAllocator(this);
+}

GPU/GPUTracking/Base/GPUReconstruction.h

@@ -47,6 +47,7 @@ struct GPUMemorySizeScalers;
 struct GPUReconstructionPipelineContext;
 struct GPUReconstructionThreading;
 class GPUROOTDumpCore;
+class ThrustVolatileAllocator;
 
 namespace gpu_reconstruction_kernels
 {
@@ -165,6 +166,7 @@ class GPUReconstruction
   void ClearAllocatedMemory(bool clearOutputs = true);
   void ReturnVolatileDeviceMemory();
   void ReturnVolatileMemory();
+  ThrustVolatileAllocator getThrustVolatileDeviceAllocator();
   void PushNonPersistentMemory(uint64_t tag);
   void PopNonPersistentMemory(RecoStep step, uint64_t tag);
   void BlockStackedMemory(GPUReconstruction* rec);

GPU/GPUTracking/Base/cuda/CMakeLists.txt

@@ -18,7 +18,7 @@ endif()
 message(STATUS "Building GPUTracking with CUDA support ${TMP_TARGET}")
 
 set(SRCS GPUReconstructionCUDA.cu GPUReconstructionCUDAGenRTC.cxx GPUReconstructionCUDAKernels.cu)
-set(HDRS GPUReconstructionCUDA.h GPUReconstructionCUDAInternals.h GPUReconstructionCUDAHelpers.inc GPUReconstructionCUDADef.h GPUReconstructionCUDAIncludesHost.h CUDAThrustHelpers.h)
+set(HDRS GPUReconstructionCUDA.h GPUReconstructionCUDAInternals.h GPUReconstructionCUDAHelpers.inc GPUReconstructionCUDADef.h GPUReconstructionCUDAIncludesHost.h)
 # -------------------------------- Prepare RTC -------------------------------------------------------
 enable_language(ASM)
 if(ALIGPU_BUILD_TYPE STREQUAL "O2")