Revert add prefetch for USM hip allocations a6b8fa6

Author: Hugh Delaney

source/adapters/hip/context.hpp

@@ -10,7 +10,6 @@
 #pragma once
 
 #include <set>
-#include <unordered_map>
 
 #include "common.hpp"
 #include "device.hpp"
@@ -106,61 +105,9 @@ struct ur_context_handle_t_ {
 
   ur_usm_pool_handle_t getOwningURPool(umf_memory_pool_t *UMFPool);
 
-  /// We need to keep track of USM mappings in AMD HIP, as certain extra
-  /// synchronization *is* actually required for correctness.
-  /// During kernel enqueue we must dispatch a prefetch for each kernel argument
-  /// that points to a USM mapping to ensure the mapping is correctly
-  /// populated on the device (https://github.com/intel/llvm/issues/7252). Thus,
-  /// we keep track of mappings in the context, and then check against them just
-  /// before the kernel is launched. The stream against which the kernel is
-  /// launched is not known until enqueue time, but the USM mappings can happen
-  /// at any time. Thus, they are tracked on the context used for the urUSM*
-  /// mapping.
-  ///
-  /// The three utility function are simple wrappers around a mapping from a
-  /// pointer to a size.
-  void addUSMMapping(void *Ptr, size_t Size) {
-    std::lock_guard<std::mutex> Guard(Mutex);
-    assert(USMMappings.find(Ptr) == USMMappings.end() &&
-           "mapping already exists");
-    USMMappings[Ptr] = Size;
-  }
-
-  void removeUSMMapping(const void *Ptr) {
-    std::lock_guard<std::mutex> guard(Mutex);
-    auto It = USMMappings.find(Ptr);
-    if (It != USMMappings.end())
-      USMMappings.erase(It);
-  }
-
-  std::pair<const void *, size_t> getUSMMapping(const void *Ptr) {
-    std::lock_guard<std::mutex> Guard(Mutex);
-    auto It = USMMappings.find(Ptr);
-    // The simple case is the fast case...
-    if (It != USMMappings.end())
-      return *It;
-
-    // ... but in the failure case we have to fall back to a full scan to search
-    // for "offset" pointers in case the user passes in the middle of an
-    // allocation. We have to do some not-so-ordained-by-the-standard ordered
-    // comparisons of pointers here, but it'll work on all platforms we support.
-    uintptr_t PtrVal = (uintptr_t)Ptr;
-    for (std::pair<const void *, size_t> Pair : USMMappings) {
-      uintptr_t BaseAddr = (uintptr_t)Pair.first;
-      uintptr_t EndAddr = BaseAddr + Pair.second;
-      if (PtrVal > BaseAddr && PtrVal < EndAddr) {
-        // If we've found something now, offset *must* be nonzero
-        assert(Pair.second);
-        return Pair;
-      }
-    }
-    return {nullptr, 0};
-  }
-
 private:
   std::mutex Mutex;
   std::vector<deleter_data> ExtendedDeleters;
-  std::unordered_map<const void *, size_t> USMMappings;
   std::set<ur_usm_pool_handle_t> PoolHandles;
 };
 

source/adapters/hip/enqueue.cpp

@@ -258,22 +258,13 @@ UR_APIEXPORT ur_result_t UR_APICALL urEnqueueKernelLaunch(
   try {
     ur_device_handle_t Dev = hQueue->getDevice();
     ScopedContext Active(Dev);
-    ur_context_handle_t Ctx = hQueue->getContext();
 
     uint32_t StreamToken;
     ur_stream_quard Guard;
     hipStream_t HIPStream = hQueue->getNextComputeStream(
         numEventsInWaitList, phEventWaitList, Guard, &StreamToken);
     hipFunction_t HIPFunc = hKernel->get();
 
-    hipDevice_t HIPDev = Dev->get();
-    for (const void *P : hKernel->getPtrArgs()) {
-      auto [Addr, Size] = Ctx->getUSMMapping(P);
-      if (!Addr)
-        continue;
-      if (hipMemPrefetchAsync(Addr, Size, HIPDev, HIPStream) != hipSuccess)
-        return UR_RESULT_ERROR_INVALID_KERNEL_ARGS;
-    }
     Result = enqueueEventsWait(hQueue, HIPStream, numEventsInWaitList,
                                phEventWaitList);
 
@@ -315,7 +306,7 @@ UR_APIEXPORT ur_result_t UR_APICALL urEnqueueKernelLaunch(
       int DeviceMaxLocalMem = 0;
       UR_CHECK_ERROR(hipDeviceGetAttribute(
           &DeviceMaxLocalMem, hipDeviceAttributeMaxSharedMemoryPerBlock,
-          HIPDev));
+          Dev->get()));
 
       static const int EnvVal = std::atoi(LocalMemSzPtr);
       if (EnvVal <= 0 || EnvVal > DeviceMaxLocalMem) {

source/adapters/hip/kernel.cpp

@@ -259,7 +259,7 @@ urKernelGetSubGroupInfo(ur_kernel_handle_t hKernel, ur_device_handle_t hDevice,
 UR_APIEXPORT ur_result_t UR_APICALL urKernelSetArgPointer(
     ur_kernel_handle_t hKernel, uint32_t argIndex,
     const ur_kernel_arg_pointer_properties_t *, const void *pArgValue) {
-  hKernel->setKernelPtrArg(argIndex, sizeof(pArgValue), pArgValue);
+  hKernel->setKernelArg(argIndex, sizeof(pArgValue), pArgValue);
   return UR_RESULT_SUCCESS;
 }
 

source/adapters/hip/kernel.hpp

@@ -14,7 +14,6 @@
 #include <atomic>
 #include <cassert>
 #include <numeric>
-#include <set>
 
 #include "program.hpp"
 
@@ -58,7 +57,6 @@ struct ur_kernel_handle_t_ {
     args_size_t ParamSizes;
     args_index_t Indices;
     args_size_t OffsetPerIndex;
-    std::set<const void *> PtrArgs;
 
     std::uint32_t ImplicitOffsetArgs[3] = {0, 0, 0};
 
@@ -179,19 +177,6 @@ struct ur_kernel_handle_t_ {
     Args.addArg(Index, Size, Arg);
   }
 
-  /// We track all pointer arguments to be able to issue prefetches at enqueue
-  /// time
-  void setKernelPtrArg(int Index, size_t Size, const void *PtrArg) {
-    Args.PtrArgs.insert(*static_cast<void *const *>(PtrArg));
-    setKernelArg(Index, Size, PtrArg);
-  }
-
-  bool isPtrArg(const void *ptr) {
-    return Args.PtrArgs.find(ptr) != Args.PtrArgs.end();
-  }
-
-  std::set<const void *> &getPtrArgs() { return Args.PtrArgs; }
-
   void setKernelLocalArg(int Index, size_t Size) {
     Args.addLocalArg(Index, Size);
   }