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[amdgpu] D2D memcpy via streams and HSA (#69977)

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hsa_amd_memory_async_copy can handle device to device copies if passed
the corresponding parameters.

No functional change - currently D2D copy goes through a fallback in
libomptarget that stages through a host malloc, after this it goes
directly through HSA.

Works under exactly the situations that HSA works. Verified locally on a
performance benchmark. Hoping to attract further testing from internal
developers after it lands.
This commit is contained in:
Jon Chesterfield 2023-10-24 00:05:04 +01:00 committed by GitHub
parent f0f5fdf73d
commit 840d0b7e03
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1 changed files with 51 additions and 8 deletions
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59
openmp/libomptarget/plugins-nextgen/amdgpu/src/rtl.cpp
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@ -1331,6 +1331,42 @@ public:
return Plugin::check(Status, "Error in hsa_amd_memory_async_copy: %s");
}
// AMDGPUDeviceTy is incomplete here, passing the underlying agent instead
Error pushMemoryCopyD2DAsync(void *Dst, hsa_agent_t DstAgent, const void *Src,
hsa_agent_t SrcAgent, uint64_t CopySize) {
AMDGPUSignalTy *OutputSignal;
if (auto Err = SignalManager.getResources(/*Num=*/1, &OutputSignal))
return Err;
OutputSignal->reset();
OutputSignal->increaseUseCount();
std::lock_guard<std::mutex> Lock(Mutex);
// Consume stream slot and compute dependencies.
auto [Curr, InputSignal] = consume(OutputSignal);
// Avoid defining the input dependency if already satisfied.
if (InputSignal && !InputSignal->load())
InputSignal = nullptr;
// The agents need to have access to the corresponding memory
// This is presently only true if the pointers were originally
// allocated by this runtime or the caller made the appropriate
// access calls.
hsa_status_t Status;
if (InputSignal && InputSignal->load()) {
hsa_signal_t InputSignalRaw = InputSignal->get();
Status =
hsa_amd_memory_async_copy(Dst, DstAgent, Src, SrcAgent, CopySize, 1,
&InputSignalRaw, OutputSignal->get());
} else
Status = hsa_amd_memory_async_copy(Dst, DstAgent, Src, SrcAgent, CopySize,
0, nullptr, OutputSignal->get());
return Plugin::check(Status, "Error in D2D hsa_amd_memory_async_copy: %s");
}
/// Synchronize with the stream. The current thread waits until all operations
/// are finalized and it performs the pending post actions (i.e., releasing
/// intermediate buffers).
@ -2250,14 +2286,20 @@ struct AMDGPUDeviceTy : public GenericDeviceTy, AMDGenericDeviceTy {
PinnedMemoryManager);
}
/// Exchange data between two devices within the plugin. This function is not
/// supported in this plugin.
/// Exchange data between two devices within the plugin.
Error dataExchangeImpl(const void *SrcPtr, GenericDeviceTy &DstGenericDevice,
void *DstPtr, int64_t Size,
AsyncInfoWrapperTy &AsyncInfoWrapper) override {
// This function should never be called because the function
// AMDGPUPluginTy::isDataExchangable() returns false.
return Plugin::error("dataExchangeImpl not supported");
AMDGPUDeviceTy &DstDevice = static_cast<AMDGPUDeviceTy &>(DstGenericDevice);
AMDGPUStreamTy *Stream = nullptr;
if (auto Err = getStream(AsyncInfoWrapper, Stream))
return Err;
if (Size <= 0)
return Plugin::success();
return Stream->pushMemoryCopyD2DAsync(DstPtr, DstDevice.getAgent(), SrcPtr,
getAgent(), (uint64_t)Size);
}
/// Initialize the async info for interoperability purposes.
@ -2897,9 +2939,8 @@ struct AMDGPUPluginTy final : public GenericPluginTy {
return true;
}
/// This plugin does not support exchanging data between two devices.
bool isDataExchangable(int32_t SrcDeviceId, int32_t DstDeviceId) override {
return false;
return true;
}
/// Get the host device instance.
@ -3174,8 +3215,10 @@ void *AMDGPUDeviceTy::allocate(size_t Size, void *, TargetAllocTy Kind) {
return nullptr;
}
if (Alloc && (Kind == TARGET_ALLOC_HOST || Kind == TARGET_ALLOC_SHARED)) {
if (Alloc) {
auto &KernelAgents = Plugin::get<AMDGPUPluginTy>().getKernelAgents();
// Inherently necessary for host or shared allocations
// Also enabled for device memory to allow device to device memcpy
// Enable all kernel agents to access the buffer.
if (auto Err = MemoryPool->enableAccess(Alloc, Size, KernelAgents)) {