Device Memory Access

Functions
hipError_t	hipDeviceCanAccessPeer (int *canAccessPeer, int device, int peerDevice)
	Determine if a device can access a peer's memory. More...
hipError_t	hipDeviceDisablePeerAccess (int peerDevice)
	Disables registering memory on peerDevice for direct access from the current device. More...
hipError_t	hipDeviceEnablePeerAccess (int peerDevice, unsigned int flags)
	Enables registering memory on peerDevice for direct access from the current device. More...
hipError_t	hipMemcpyPeer (void *dst, int dstDevice, const void *src, int srcDevice, size_t sizeBytes)
	Copies memory from one device to memory on another device. More...
hipError_t	hipMemcpyPeerAsync (void *dst, int dstDevice, const void *src, int srcDevice, size_t sizeBytes, hipStream_t stream=0)
	Copies memory from one device to memory on another device. More...

Detailed Description

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Function Documentation

hipError_t hipDeviceCanAccessPeer	(	int *	canAccessPeer,
		int	device,
		int	peerDevice
	)

Determine if a device can access a peer's memory.

Parameters

[out]	canAccessPeer	returns true if specified devices are peers.
[in]	device
[in]	peerDevice	Returns "1" in canAccessPeer if the specified device is capable of directly accessing memory physically located on peerDevice , or "0" if not.

Warning

HCC returns 0 in *canAccessPeer ; Need to update this function when RT supports P2P

hipError_t hipDeviceDisablePeerAccess

(

int

peerDevice

)

Disables registering memory on peerDevice for direct access from the current device.

If there are any allocations on peerDevice which were registered in the current device using hipPeerRegister() then these allocations will be automatically unregistered. Returns hipErrorPeerAccessNotEnabled if direct access to memory on peerDevice has not yet been enabled from the current device.

Parameters

[in]

peerDevice

TODO:cudaErrorPeerAccessNotEnabled and cudaErrorInvalidDevice error not supported in HIP, return hipErrorUnknown Returns hipSuccess, hipErrorUnknown

Warning

Need to update this function when RT supports P2P

hipError_t hipDeviceEnablePeerAccess	(	int	peerDevice,
		unsigned int	flags
	)

Enables registering memory on peerDevice for direct access from the current device.

Parameters

[in]	peerDevice
[in]	flags	TODO:cudaErrorInvalidDevice error not supported in HIP, return hipErrorUnknown Returns hipSuccess, hipErrorInvalidDevice, hipErrorInvalidValue, hipErrorUnknown

Warning

Need to update this function when RT supports P2P

hipError_t hipMemcpyPeer	(	void *	dst,
		int	dstDevice,
		const void *	src,
		int	srcDevice,
		size_t	sizeBytes
	)

Copies memory from one device to memory on another device.

Parameters

[out]	dst	- Destination device pointer.
[in]	dstDevice	- Destination device
[in]	src	- Source device pointer
[in]	srcDevice	- Source device
[in]	sizeBytes	- Size of memory copy in bytes

Returns hipSuccess, hipErrorInvalidValue, hipErrorInvalidDevice

hipError_t hipMemcpyPeerAsync	(	void *	dst,
		int	dstDevice,
		const void *	src,
		int	srcDevice,
		size_t	sizeBytes,
		hipStream_t	stream
	)

Copies memory from one device to memory on another device.

Parameters

[out]	dst	- Destination device pointer.
[in]	dstDevice	- Destination device
[in]	src	- Source device pointer
[in]	srcDevice	- Source device
[in]	sizeBytes	- Size of memory copy in bytes
[in]	stream	- Stream identifier

Returns hipSuccess, hipErrorInvalidValue, hipErrorInvalidDevice

Bug:

This function uses a synchronous copy