Check if GPU has over 2GB of memory

If the user's machine contains no OpenCL device that has enough GPU
memory then don't allow creation of a GPU miner. Instead default to CPU.

ethminer/MinerAux.h

@@ -171,8 +171,16 @@ public:
 			m_minerType = MinerType::CPU;
 		else if (arg == "-G" || arg == "--opencl")
 		{
-			m_minerType = MinerType::GPU;
+			if (!ProofOfWork::GPUMiner::haveSufficientGPUMemory())
-			miningThreads = 1;
+			{
+				cout << "No GPU device with sufficient memory was found. Defaulting to CPU" << endl;
+				m_minerType = MinerType::CPU;
+			}
+			else
+			{
+				m_minerType = MinerType::GPU;
+				miningThreads = 1;
+			}
 		}
 		else if (arg == "--no-precompute")
 		{

libethash-cl/ethash_cl_miner.cpp

@@ -35,6 +35,7 @@
 #include "ethash_cl_miner_kernel.h"
 
 #define ETHASH_BYTES 32
+#define ETHASH_CL_MINIMUM_MEMORY 2000000000
 
 // workaround lame platforms
 #if !CL_VERSION_1_2
@@ -47,6 +48,9 @@
 
 using namespace std;
 
+// TODO: If at any point we can use libdevcore in here then we should switch to using a LogChannel
+#define ETHCL_LOG(_contents) cout << "[OPENCL]:" << _contents << endl
+
 static void add_definition(std::string& source, char const* id, unsigned value)
 {
 	char buf[256];
@@ -72,7 +76,7 @@ std::string ethash_cl_miner::platform_info(unsigned _platformId, unsigned _devic
 	cl::Platform::get(&platforms);
 	if (platforms.empty())
 	{
-		cout << "No OpenCL platforms found." << endl;
+		ETHCL_LOG("No OpenCL platforms found.");
 		return std::string();
 	}
 
@@ -82,7 +86,7 @@ std::string ethash_cl_miner::platform_info(unsigned _platformId, unsigned _devic
 	platforms[platform_num].getDevices(CL_DEVICE_TYPE_ALL, &devices);
 	if (devices.empty())
 	{
-		cout << "No OpenCL devices found." << endl;
+		ETHCL_LOG("No OpenCL devices found.");
 		return std::string();
 	}
 
@@ -107,7 +111,7 @@ unsigned ethash_cl_miner::get_num_devices(unsigned _platformId)
 	cl::Platform::get(&platforms);
 	if (platforms.empty())
 	{
-		cout << "No OpenCL platforms found." << endl;
+		ETHCL_LOG("No OpenCL platforms found.");
 		return 0;
 	}
 
@@ -116,12 +120,53 @@ unsigned ethash_cl_miner::get_num_devices(unsigned _platformId)
 	platforms[platform_num].getDevices(CL_DEVICE_TYPE_ALL, &devices);
 	if (devices.empty())
 	{
-		cout << "No OpenCL devices found." << endl;
+		ETHCL_LOG("No OpenCL devices found.");
 		return 0;
 	}
 	return devices.size();
 }
 
+bool ethash_cl_miner::haveSufficientGPUMemory(unsigned _platformId)
+{
+	std::vector<cl::Platform> platforms;
+	cl::Platform::get(&platforms);
+	if (platforms.empty())
+	{
+		ETHCL_LOG("No OpenCL platforms found.");
+		return false;
+	}
+
+	std::vector<cl::Device> devices;
+	unsigned platform_num = std::min<unsigned>(_platformId, platforms.size() - 1);
+	platforms[platform_num].getDevices(CL_DEVICE_TYPE_ALL, &devices);
+	if (devices.empty())
+	{
+		ETHCL_LOG("No OpenCL devices found.");
+		return false;
+	}
+
+	for (cl::Device const& device: devices)
+	{
+		cl_ulong result;
+		device.getInfo(CL_DEVICE_GLOBAL_MEM_SIZE, &result);
+		if (result >= ETHASH_CL_MINIMUM_MEMORY)
+		{
+			ETHCL_LOG(
+				"Found suitable OpenCL device [" << device.getInfo<CL_DEVICE_NAME>()
+				<< "] with " << result << " bytes of GPU memory"
+			);
+			return true;
+		}
+		else
+			ETHCL_LOG(
+				"OpenCL device " << device.getInfo<CL_DEVICE_NAME>()
+				<< " has insufficient GPU memory." << result <<
+				" bytes of memory found < " << ETHASH_CL_MINIMUM_MEMORY << " bytes of memory required"
+			);
+	}
+	return false;
+}
+
 void ethash_cl_miner::finish()
 {
 	if (m_queue())
@@ -135,7 +180,7 @@ bool ethash_cl_miner::init(uint8_t const* _dag, uint64_t _dagSize, unsigned work
 	cl::Platform::get(&platforms);
 	if (platforms.empty())
 	{
-		cout << "No OpenCL platforms found." << endl;
+		ETHCL_LOG("No OpenCL platforms found.");
 		return false;
 	}
 
@@ -143,25 +188,25 @@ bool ethash_cl_miner::init(uint8_t const* _dag, uint64_t _dagSize, unsigned work
 
 	_platformId = std::min<unsigned>(_platformId, platforms.size() - 1);
 
-	cout << "Using platform: " << platforms[_platformId].getInfo<CL_PLATFORM_NAME>().c_str() << endl;
+	ETHCL_LOG("Using platform: " << platforms[_platformId].getInfo<CL_PLATFORM_NAME>().c_str());
 
 	// get GPU device of the default platform
 	std::vector<cl::Device> devices;
 	platforms[_platformId].getDevices(CL_DEVICE_TYPE_ALL, &devices);
 	if (devices.empty())
 	{
-		cout << "No OpenCL devices found." << endl;
+		ETHCL_LOG("No OpenCL devices found.");
 		return false;
 	}
 
 	// use selected device
 	cl::Device& device = devices[std::min<unsigned>(_deviceId, devices.size() - 1)];
 	std::string device_version = device.getInfo<CL_DEVICE_VERSION>();
-	cout << "Using device: " << device.getInfo<CL_DEVICE_NAME>().c_str() << "(" << device_version.c_str() << ")" << endl;
+	ETHCL_LOG("Using device: " << device.getInfo<CL_DEVICE_NAME>().c_str() << "(" << device_version.c_str() << ")");
 
 	if (strncmp("OpenCL 1.0", device_version.c_str(), 10) == 0)
 	{
-		cout << "OpenCL 1.0 is not supported." << endl;
+		ETHCL_LOG("OpenCL 1.0 is not supported.");
 		return false;
 	}
 	if (strncmp("OpenCL 1.1", device_version.c_str(), 10) == 0)
@@ -193,7 +238,7 @@ bool ethash_cl_miner::init(uint8_t const* _dag, uint64_t _dagSize, unsigned work
 	}
 	catch (cl::Error err)
 	{
-		cout << program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(device).c_str();
+		ETHCL_LOG(program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(device).c_str());
 		return false;
 	}
 	m_hash_kernel = cl::Kernel(program, "ethash_hash");

libethash-cl/ethash_cl_miner.h

@@ -35,6 +35,7 @@ public:
 	static unsigned get_num_platforms();
 	static unsigned get_num_devices(unsigned _platformId = 0);
 	static std::string platform_info(unsigned _platformId = 0, unsigned _deviceId = 0);
+	static bool haveSufficientGPUMemory(unsigned _platformId = 0);
 
 	bool init(uint8_t const* _dag, uint64_t _dagSize, unsigned workgroup_size = 64, unsigned _platformId = 0, unsigned _deviceId = 0);
 	void finish();

libethcore/Ethash.cpp

@@ -363,6 +363,11 @@ void Ethash::GPUMiner::pause()
 	stopWorking();
 }
 
+bool Ethash::GPUMiner::haveSufficientGPUMemory()
+{
+	return ethash_cl_miner::haveSufficientGPUMemory(s_platformId);
+}
+
 std::string Ethash::GPUMiner::platformInfo()
 {
 	return ethash_cl_miner::platform_info(s_platformId, s_deviceId);

libethcore/Ethash.h

@@ -115,6 +115,7 @@ public:
 
 		static unsigned instances() { return s_numInstances > 0 ? s_numInstances : 1; }
 		static std::string platformInfo();
+		static bool haveSufficientGPUMemory();
 		static unsigned getNumDevices();
 		static void setDefaultPlatform(unsigned _id) { s_platformId = _id; }
 		static void setDefaultDevice(unsigned _id) { s_deviceId = _id; }