Quote from: Genoil on December 02, 2015, 12:12:36 PM

Quote from: virasog on December 01, 2015, 01:59:38 PM

From the 640MB chunk size above, the hash rate changes between 20 to 40 MHz all the time, then it the difference reduces from 20 MH/s to a much lower value. Does it indicate an optimisation opportunity.

Can anybody make the chunk work in the ethminers?

The latest ethminer does not display the hash rate, it makes it difficult to compare the results. I wonder this can be added as well.

Code:

catch (cl::Error const& err)
{
ETHCL_LOG("Allocating/mapping single buffer failed with: " << err.what() << "(" << err.err() << "). GPU can't allocate the DAG in a single chunk. Bailing.");
return false;
#if 0 // Disabling chunking for release since it seems not to work. Never manages to mine a block. TODO: Fix when time is found.
int errCode = err.err();
if (errCode != CL_INVALID_BUFFER_SIZE || errCode != CL_MEM_OBJECT_ALLOCATION_FAILURE)
ETHCL_LOG("Allocating/mapping single buffer failed with: " << err.what() << "(" << errCode << ")");
cl_ulong result;
// if we fail midway on the try above make sure we start clean
m_dagChunks.clear();
device.getInfo(CL_DEVICE_MAX_MEM_ALLOC_SIZE, &result);
ETHCL_LOG(
"Failed to allocate 1 big chunk. Max allocateable memory is "
<< result << ". Trying to allocate 4 chunks."
);
// The OpenCL kernel has a hard coded number of 4 chunks at the moment
m_dagChunksCount = 4;
for (unsigned i = 0; i < m_dagChunksCount; i++)
{
// TODO Note: If we ever change to _dagChunksNum other than 4, then the size would need recalculation
ETHCL_LOG("Creating buffer for chunk " << i);
m_dagChunks.push_back(cl::Buffer(
m_context,
CL_MEM_READ_ONLY,
(i == 3) ? (_dagSize - 3 * ((_dagSize >> 9) << 7)) : (_dagSize >> 9) << 7
));
}
ETHCL_LOG("Loading chunk kernels");
m_hashKernel = cl::Kernel(program, "ethash_hash_chunks");
m_searchKernel = cl::Kernel(program, "ethash_search_chunks");
// TODO Note: If we ever change to _dagChunksNum other than 4, then the size would need recalculation
void* dag_ptr[4];
for (unsigned i = 0; i < m_dagChunksCount; i++)
{
ETHCL_LOG("Mapping chunk " << i);
dag_ptr[i] = m_queue.enqueueMapBuffer(m_dagChunks[i], true, m_openclOnePointOne ? CL_MAP_WRITE : CL_MAP_WRITE_INVALIDATE_REGION, 0, (i == 3) ? (_dagSize - 3 * ((_dagSize >> 9) << 7)) : (_dagSize >> 9) << 7);
}
for (unsigned i = 0; i < m_dagChunksCount; i++)
{
memcpy(dag_ptr[i], (char *)_dag + i*((_dagSize >> 9) << 7), (i == 3) ? (_dagSize - 3 * ((_dagSize >> 9) << 7)) : (_dagSize >> 9) << 7);
m_queue.enqueueUnmapMemObject(m_dagChunks[i], dag_ptr[i]);
}
#endif
}

It may be an oppurtunity for an optimization. The chunked implementation in current ethminer is disabled because it doesn't work. I'll see if I can find some time to check if this could work in ethminer.

If you can make it work, you save a lot of AMD card from being useful in a month or two.

By the way, why the latest ethminer (1.1.0) does not has rate?