def _check_cand(candidates, outer_edges):
for cname, (cand, nstate, indices) in candidates.items():
if all(me == 0
for i, me in enumerate(cand.subset.min_element())
if i in indices):
ignore.add(cname)
continue
# Ensure outer memlets begin with 0
outer_edge = next(iter(outer_edges(nsdfg, cname)))
if any(me != 0 for i, me in enumerate(
outer_edge.data.subset.min_element()) if i in indices):
ignore.add(cname)
continue
# Check w.r.t. loops
if len(nstate.ranges) > 0:
# Re-annotate loop ranges, in case someone changed them
# TODO: Move out of here!
nstate.ranges = {}
from dace.sdfg.propagation import _annotate_loop_ranges
_annotate_loop_ranges(nsdfg.sdfg, [])
memlet = propagation.propagate_subset(
[cand], nsdfg.sdfg.arrays[cname],
sorted(nstate.ranges.keys()),
subsets.Range([
v.ndrange()[0]
for _, v in sorted(nstate.ranges.items())
]))
if all(me == 0
for i, me in enumerate(memlet.subset.min_element())
if i in indices):
ignore.add(cname)
continue
# Modify memlet to propagated one
candidates[cname] = (memlet, nstate, indices)
else:
memlet = cand
# If there are any symbols here that are not defined
# in "defined_symbols"
missing_symbols = (memlet.free_symbols -
set(nsdfg.symbol_mapping.keys()))
if missing_symbols:
ignore.add(cname)
continue
def expansion(node: 'Reduce', state: SDFGState, sdfg: SDFG):
from dace.codegen.prettycode import CodeIOStream
from dace.codegen.targets.cpp import unparse_cr_split, cpp_array_expr
node.validate(sdfg, state)
input_edge: graph.MultiConnectorEdge = state.in_edges(node)[0]
output_edge: graph.MultiConnectorEdge = state.out_edges(node)[0]
input_dims = len(input_edge.data.subset)
output_dims = len(output_edge.data.subset)
input_data = sdfg.arrays[input_edge.data.data]
output_data = sdfg.arrays[output_edge.data.data]
# Setup all locations in which code will be written
cuda_globalcode = CodeIOStream()
cuda_initcode = CodeIOStream()
cuda_exitcode = CodeIOStream()
host_globalcode = CodeIOStream()
host_localcode = CodeIOStream()
output_memlet = output_edge.data
# Try to autodetect reduction type
redtype = detect_reduction_type(node.wcr)
node_id = state.node_id(node)
state_id = sdfg.node_id(state)
idstr = '{sdfg}_{state}_{node}'.format(sdfg=sdfg.name,
state=state_id,
node=node_id)
if node.out_connectors:
dtype = next(node.out_connectors.values())
else:
dtype = sdfg.arrays[output_memlet.data].dtype
output_type = dtype.ctype
if node.identity is None:
raise ValueError('For device reduce nodes, initial value must be '
'specified')
# Create a functor or use an existing one for reduction
if redtype == dtypes.ReductionType.Custom:
body, [arg1, arg2] = unparse_cr_split(sdfg, node.wcr)
cuda_globalcode.write(
"""
struct __reduce_{id} {{
template <typename T>
DACE_HDFI T operator()(const T &{arg1}, const T &{arg2}) const {{
{contents}
}}
}};""".format(id=idstr, arg1=arg1, arg2=arg2, contents=body), sdfg,
state_id, node_id)
reduce_op = ', __reduce_' + idstr + '(), ' + symstr(node.identity)
elif redtype in ExpandReduceCUDADevice._SPECIAL_RTYPES:
reduce_op = ''
else:
credtype = 'dace::ReductionType::' + str(
redtype)[str(redtype).find('.') + 1:]
reduce_op = ((', dace::_wcr_fixed<%s, %s>()' %
(credtype, output_type)) + ', ' +
symstr(node.identity))
# Obtain some SDFG-related information
input_memlet = input_edge.data
reduce_shape = input_memlet.subset.bounding_box_size()
num_items = ' * '.join(symstr(s) for s in reduce_shape)
overapprox_memlet = dcpy(input_memlet)
if any(
str(s) not in sdfg.free_symbols.union(sdfg.constants.keys())
for s in overapprox_memlet.subset.free_symbols):
propagation.propagate_states(sdfg)
for p, r in state.ranges.items():
overapprox_memlet = propagation.propagate_subset(
[overapprox_memlet], input_data, [p], r)
overapprox_shape = overapprox_memlet.subset.bounding_box_size()
overapprox_items = ' * '.join(symstr(s) for s in overapprox_shape)
input_dims = input_memlet.subset.dims()
output_dims = output_memlet.subset.data_dims()
reduce_all_axes = (node.axes is None or len(node.axes) == input_dims)
if reduce_all_axes:
reduce_last_axes = False
else:
reduce_last_axes = sorted(node.axes) == list(
range(input_dims - len(node.axes), input_dims))
if not reduce_all_axes and not reduce_last_axes:
warnings.warn(
'Multiple axis reductions not supported with this expansion. '
'Falling back to the pure expansion.')
return ExpandReducePureSequentialDim.expansion(node, state, sdfg)
# Verify that data is on the GPU
if input_data.storage not in [
dtypes.StorageType.GPU_Global, dtypes.StorageType.CPU_Pinned
]:
warnings.warn('Input of GPU reduction must either reside '
' in global GPU memory or pinned CPU memory')
return ExpandReducePure.expansion(node, state, sdfg)
if output_data.storage not in [
dtypes.StorageType.GPU_Global, dtypes.StorageType.CPU_Pinned
]:
warnings.warn('Output of GPU reduction must either reside '
' in global GPU memory or pinned CPU memory')
return ExpandReducePure.expansion(node, state, sdfg)
# Determine reduction type
kname = (ExpandReduceCUDADevice._SPECIAL_RTYPES[redtype] if redtype
in ExpandReduceCUDADevice._SPECIAL_RTYPES else 'Reduce')
# Create temp memory for this GPU
cuda_globalcode.write(
"""
void *__cub_storage_{sdfg}_{state}_{node} = NULL;
size_t __cub_ssize_{sdfg}_{state}_{node} = 0;
""".format(sdfg=sdfg.name, state=state_id, node=node_id), sdfg,
state_id, node)
if reduce_all_axes:
reduce_type = 'DeviceReduce'
reduce_range = overapprox_items
reduce_range_def = 'size_t num_items'
reduce_range_use = 'num_items'
reduce_range_call = num_items
elif reduce_last_axes:
num_reduce_axes = len(node.axes)
not_reduce_axes = reduce_shape[:-num_reduce_axes]
reduce_axes = reduce_shape[-num_reduce_axes:]
overapprox_not_reduce_axes = overapprox_shape[:-num_reduce_axes]
overapprox_reduce_axes = overapprox_shape[-num_reduce_axes:]
num_segments = ' * '.join([symstr(s) for s in not_reduce_axes])
segment_size = ' * '.join([symstr(s) for s in reduce_axes])
overapprox_num_segments = ' * '.join(
[symstr(s) for s in overapprox_not_reduce_axes])
overapprox_segment_size = ' * '.join(
[symstr(s) for s in overapprox_reduce_axes])
reduce_type = 'DeviceSegmentedReduce'
iterator = 'dace::stridedIterator({size})'.format(
size=overapprox_segment_size)
reduce_range = '{num}, {it}, {it} + 1'.format(
num=overapprox_num_segments, it=iterator)
reduce_range_def = 'size_t num_segments, size_t segment_size'
iterator_use = 'dace::stridedIterator(segment_size)'
reduce_range_use = 'num_segments, {it}, {it} + 1'.format(
it=iterator_use)
reduce_range_call = '%s, %s' % (num_segments, segment_size)
# Call CUB to get the storage size, allocate and free it
cuda_initcode.write(
"""
cub::{reduce_type}::{kname}(nullptr, __cub_ssize_{sdfg}_{state}_{node},
({intype}*)nullptr, ({outtype}*)nullptr, {reduce_range}{redop});
cudaMalloc(&__cub_storage_{sdfg}_{state}_{node}, __cub_ssize_{sdfg}_{state}_{node});
""".format(sdfg=sdfg.name,
state=state_id,
node=node_id,
reduce_type=reduce_type,
reduce_range=reduce_range,
redop=reduce_op,
intype=input_data.dtype.ctype,
outtype=output_data.dtype.ctype,
kname=kname), sdfg, state_id, node)
cuda_exitcode.write(
'cudaFree(__cub_storage_{sdfg}_{state}_{node});'.format(
sdfg=sdfg.name, state=state_id, node=node_id), sdfg, state_id,
node)
# Write reduction function definition
cuda_globalcode.write("""
DACE_EXPORTED void __dace_reduce_{id}({intype} *input, {outtype} *output, {reduce_range_def}, cudaStream_t stream);
void __dace_reduce_{id}({intype} *input, {outtype} *output, {reduce_range_def}, cudaStream_t stream)
{{
cub::{reduce_type}::{kname}(__cub_storage_{id}, __cub_ssize_{id},
input, output, {reduce_range_use}{redop}, stream);
}}
""".format(id=idstr,
intype=input_data.dtype.ctype,
outtype=output_data.dtype.ctype,
reduce_type=reduce_type,
reduce_range_def=reduce_range_def,
reduce_range_use=reduce_range_use,
kname=kname,
redop=reduce_op))
# Write reduction function definition in caller file
host_globalcode.write(
"""
DACE_EXPORTED void __dace_reduce_{id}({intype} *input, {outtype} *output, {reduce_range_def}, cudaStream_t stream);
""".format(id=idstr,
reduce_range_def=reduce_range_def,
intype=input_data.dtype.ctype,
outtype=output_data.dtype.ctype), sdfg, state_id, node)
# Call reduction function where necessary
host_localcode.write(
'__dace_reduce_{id}(_in, _out, {reduce_range_call}, __dace_current_stream);'
.format(id=idstr, reduce_range_call=reduce_range_call))
# Make tasklet
tnode = dace.nodes.Tasklet('reduce',
{'_in': dace.pointer(input_data.dtype)},
{'_out': dace.pointer(output_data.dtype)},
host_localcode.getvalue(),
language=dace.Language.CPP)
# Add the rest of the code
sdfg.append_global_code(host_globalcode.getvalue())
sdfg.append_global_code(cuda_globalcode.getvalue(), 'cuda')
sdfg.append_init_code(cuda_initcode.getvalue(), 'cuda')
sdfg.append_exit_code(cuda_exitcode.getvalue(), 'cuda')
# Rename outer connectors and add to node
input_edge._dst_conn = '_in'
output_edge._src_conn = '_out'
node.add_in_connector('_in')
node.add_out_connector('_out')
return tnode
def can_be_applied(self, graph, candidate, expr_index, sdfg, strict=False):
# Is this even a loop
if not DetectLoop.can_be_applied(graph, candidate, expr_index, sdfg,
strict):
return False
guard = graph.node(candidate[DetectLoop._loop_guard])
begin = graph.node(candidate[DetectLoop._loop_begin])
# Guard state should not contain any dataflow
if len(guard.nodes()) != 0:
return False
# If loop cannot be detected, fail
found = find_for_loop(graph, guard, begin,
itervar=self.itervar)
if not found:
return False
itervar, (start, end, step), (_, body_end) = found
# We cannot handle symbols read from data containers unless they are
# scalar
for expr in (start, end, step):
if symbolic.contains_sympy_functions(expr):
return False
# Find all loop-body states
states = set([body_end])
to_visit = [begin]
while to_visit:
state = to_visit.pop(0)
if state is body_end:
continue
for _, dst, _ in graph.out_edges(state):
if dst not in states:
to_visit.append(dst)
states.add(state)
write_set = set()
for state in states:
_, wset = state.read_and_write_sets()
write_set |= wset
# Get access nodes from other states to isolate local loop variables
other_access_nodes = set()
for state in sdfg.nodes():
if state in states:
continue
other_access_nodes |= set(n.data for n in state.data_nodes()
if sdfg.arrays[n.data].transient)
# Add non-transient nodes from loop state
for state in states:
other_access_nodes |= set(n.data for n in state.data_nodes()
if not sdfg.arrays[n.data].transient)
write_memlets = defaultdict(list)
itersym = symbolic.pystr_to_symbolic(itervar)
a = sp.Wild('a', exclude=[itersym])
b = sp.Wild('b', exclude=[itersym])
for state in states:
for dn in state.data_nodes():
if dn.data not in other_access_nodes:
continue
# Take all writes that are not conflicted into consideration
if dn.data in write_set:
for e in state.in_edges(dn):
if e.data.dynamic and e.data.wcr is None:
# If pointers are involved, give up
return False
# To be sure that the value is only written at unique
# indices per loop iteration, we want to match symbols
# of the form "a*i+b" where a >= 1, and i is the iteration
# variable. The iteration variable must be used.
if e.data.wcr is None:
dst_subset = e.data.get_dst_subset(e, state)
if not _check_range(dst_subset, a, itersym, b, step):
return False
# End of check
write_memlets[dn.data].append(e.data)
# After looping over relevant writes, consider reads that may overlap
for state in states:
for dn in state.data_nodes():
if dn.data not in other_access_nodes:
continue
data = dn.data
if data in write_memlets:
# Import as necessary
from dace.sdfg.propagation import propagate_subset
for e in state.out_edges(dn):
# If the same container is both read and written, only match if
# it read and written at locations that will not create data races
if e.data.dynamic and e.data.src_subset.num_elements() != 1:
# If pointers are involved, give up
return False
src_subset = e.data.get_src_subset(e, state)
if not _check_range(src_subset, a, itersym, b, step):
return False
pread = propagate_subset([e.data], sdfg.arrays[data],
[itervar],
subsets.Range([(start, end, step)
]))
for candidate in write_memlets[data]:
# Simple case: read and write are in the same subset
if e.data.subset == candidate.subset:
break
# Propagated read does not overlap with propagated write
pwrite = propagate_subset([candidate],
sdfg.arrays[data], [itervar],
subsets.Range([(start, end,
step)]))
if subsets.intersects(pread.subset,
pwrite.subset) is False:
break
return False
# Check that the iteration variable is not used on other edges or states
# before it is reassigned
prior_states = True
for state in cfg.stateorder_topological_sort(sdfg):
# Skip all states up to guard
if prior_states:
if state is begin:
prior_states = False
continue
# We do not need to check the loop-body states
if state in states:
continue
if itervar in state.free_symbols:
return False
# Don't continue in this direction, as the variable has
# now been reassigned
# TODO: Handle case of subset of out_edges
if all(itervar in e.data.assignments
for e in sdfg.out_edges(state)):
break
return True
