CudaSelectGpu.h

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// -*- LSST-C++ -*-

/*
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 * Copyright 2008, 2009, 2010 LSST Corporation.
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namespace lsst {
namespace afw {
namespace gpu {
namespace detail {


void SetCudaDevice(int devId);

void CudaReserveDevice();

void CudaThreadExit();

// gets the preferred cuda device id from a CUDA_DEVICE environment variable
// if the CUDA_DEVICE environment variable is not set, returns -2 (preferred device not specified)
int GetPreferredCudaDevice();

// returns true when preffered device has been selected
// returns false when preffered device is not specified
// throws exception when unable to select the preffered device
bool SelectPreferredCudaDevice();

// If cuda device is already selected and reserved, does nothing
// otherwise, attempts to select the best available GPU
// throws exception when automatic selection fails
void AutoSelectCudaDevice();

// verifies basic parameters of selected cuda device
// throws exceptions when the selected GPU is not 'good enough'
// Intention was mainly to guard against integrated GPUs or very old GPUs
void VerifyCudaDevice();

// Tries to select a cuda device, but only the first time this function is called.
// All subsequent calls will return the previous result.
// To select again, set reselect to true.
// Attempts to use the preferred device.
// If a preferred device is not specified, it attempts to auto-select.
// Finally, it verifies the selected cuda device.
// returns true if gpu device was sucesssfully selected at this call or at a previous call
// returns false if gpu device selection failed at this call or at a previous call
// Throws exceptions if device selection fails due to any reason (only on a first call or on reselect)
// When noExceptions is set to true, no exceptions will be thrown.
bool TryToSelectCudaDevice(bool noExceptions, bool reselect=false);


}}}} //namespace lsst::afw::math::detail::gpu ends