Devices

In AMDGPU, all GPU devices are auto-detected by the runtime, if they're supported.

AMDGPU maintains a global default device. The default device is relevant for all kernel and GPUArray operations. If one is not specified via @roc or an equivalent interface, then the default device is used for those operations, which affects compilation and kernel launch.

The device bound to a current Julia task is accessible via AMDGPU.device method. The list of available devices can be queried with AMDGPU.devices method.

If you have a HIPDevice object, you can also switch the device with AMDGPU.device!. This will switch it only within the task it is called from.

xd1 = AMDGPU.ones(Float32, 16) # On `AMDGPU.device()` device.

AMDGPU.device!(AMDGPU.devices()[2]) # Switch to second device.
xd2 = AMDPGU.ones(Float32, 16) # On second device.

Additionally, devices have an associated numeric ID. This value is bounded between 1 and length(AMDGPU.devices()), and device 1 is the default device when AMDGPU is first loaded. The ID of the device associated with the current task can be queried with AMDGPU.device_id and changed with AMDGPU.device_id!.

AMDGPU.HIP.devices — Function

devices()

Get list of all devices.

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AMDGPU.device — Function

device()::HIPDevice

Get currently active device. This device is used when launching kernels via @roc.

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device(A::ROCArray) -> HIPDevice

Return the device associated with the array A.

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AMDGPU.device! — Function

device!(device::HIPDevice)

Switch current device being used. This switches only for a task inside which it is called.

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AMDGPU.device_id — Function

device_id() -> Int
device_id(device::HIPDevice) -> Int

Returns the numerical device ID for device or for the current AMDGPU.device().

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AMDGPU.device_id! — Function

device_id!(idx::Integer)

Sets the current device to AMDGPU.devices()[idx]. See device_id for details on the numbering semantics.

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Device Properties

AMDGPU.HIP.name — Function

name(dev::HIPDevice)::String

Get name of the device.

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AMDGPU.HIP.wavefrontsize — Function

wavefrontsize(d::HIPDevice)::Cint

Get size of the wavefront. AMD GPUs support either 32 or 64.

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AMDGPU.HIP.gcn_arch — Function

gcn_arch(d::HIPDevice)::String

Get GCN architecture for the device.

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AMDGPU.HIP.device_id — Function

device_id(d::HIPDevice)

Zero-based device ID as expected by HIP functions. Differs from AMDGPU.device_id method by 1.

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AMDGPU.HIP.properties — Function

properties(dev::HIPDevice)::hipDeviceProp_t

Get all properties for the device. See HIP documentation for hipDeviceProp_t for the meaning of each field.

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