Files
mlx/mlx/backend/cuda/fence.cpp
Awni Hannun fc00f16e30 fix
2025-11-04 07:57:32 -08:00

47 lines
1.3 KiB
C++

// Copyright © 2025 Apple Inc.
#include "mlx/fence.h"
#include "mlx/backend/cuda/allocator.h"
#include "mlx/backend/cuda/device.h"
#include "mlx/backend/cuda/event.h"
namespace mlx::core {
struct FenceImpl {
uint32_t count;
cu::AtomicEvent event;
};
Fence::Fence(Stream s) {
fence_ = std::shared_ptr<void>(
new FenceImpl{0}, [](void* ptr) { delete static_cast<FenceImpl*>(ptr); });
}
void Fence::wait(Stream s, const array&) {
auto* fence = static_cast<FenceImpl*>(fence_.get());
fence->event.wait(fence->count);
}
void Fence::update(Stream s, const array& a, bool cross_device) {
auto* fence = static_cast<FenceImpl*>(fence_.get());
if (cross_device) {
// Move to managed memory if there is a device switch
auto& cbuf =
*static_cast<cu::CudaBuffer*>(const_cast<array&>(a).buffer().ptr());
if (cbuf.device != -1) {
void* new_data;
CHECK_CUDA_ERROR(cudaMallocManaged(&new_data, cbuf.size));
cbuf.device = -1;
CHECK_CUDA_ERROR(
cudaMemcpyAsync(new_data, cbuf.data, cbuf.size, cudaMemcpyDefault));
auto& encoder = cu::device(s.device).get_command_encoder(s);
CHECK_CUDA_ERROR(cudaFreeAsync(cbuf.data, encoder.stream()));
cbuf.data = new_data;
}
}
fence->count++;
fence->event.signal(s, fence->count);
}
} // namespace mlx::core