def can_be_applied(self, graph: SDFGState, expr_index, sdfg: SDFG,
permissive) -> bool:
me = self.mapentry
if len(xfh.get_internal_scopes(graph, me, immediate=True)) == 0:
return False
# GPU map that has no predefined thread-block maps
return (me.schedule == dtypes.ScheduleType.GPU_Device
and not xfh.gpu_map_has_explicit_threadblocks(graph, me))
def apply(self, graph: SDFGState, sdfg: SDFG) -> nodes.MapEntry:
me = self.mapentry
# Add new map within map
mx = graph.exit_node(me)
new_me, new_mx = graph.add_map('warp_tile',
dict(__tid=f'0:{self.warp_size}'),
dtypes.ScheduleType.GPU_ThreadBlock)
__tid = symbolic.pystr_to_symbolic('__tid')
for e in graph.out_edges(me):
xfh.reconnect_edge_through_map(graph, e, new_me, True)
for e in graph.in_edges(mx):
xfh.reconnect_edge_through_map(graph, e, new_mx, False)
# Stride and offset all internal maps
maps_to_stride = xfh.get_internal_scopes(graph, new_me, immediate=True)
for nstate, nmap in maps_to_stride:
nsdfg = nstate.parent
nsdfg_node = nsdfg.parent_nsdfg_node
# Map cannot be partitioned across a warp
if (nmap.range.size()[-1] < self.warp_size) == True:
continue
if nsdfg is not sdfg and nsdfg_node is not None:
nsdfg_node.symbol_mapping['__tid'] = __tid
if '__tid' not in nsdfg.symbols:
nsdfg.add_symbol('__tid', dtypes.int32)
nmap.range[-1] = (nmap.range[-1][0], nmap.range[-1][1] - __tid,
nmap.range[-1][2] * self.warp_size)
subgraph = nstate.scope_subgraph(nmap)
subgraph.replace(nmap.params[-1], f'{nmap.params[-1]} + __tid')
inner_map_exit = nstate.exit_node(nmap)
# If requested, replicate maps with multiple dependent maps
if self.replicate_maps:
destinations = [
nstate.memlet_path(edge)[-1].dst
for edge in nstate.out_edges(inner_map_exit)
]
for dst in destinations:
# Transformation will not replicate map with more than one
# output
if len(destinations) != 1:
break
if not isinstance(dst, nodes.AccessNode):
continue # Not leading to access node
if not xfh.contained_in(nstate, dst, new_me):
continue # Memlet path goes out of map
if not nsdfg.arrays[dst.data].transient:
continue # Cannot modify non-transients
for edge in nstate.out_edges(dst)[1:]:
rep_subgraph = xfh.replicate_scope(
nsdfg, nstate, subgraph)
rep_edge = nstate.out_edges(
rep_subgraph.sink_nodes()[0])[0]
# Add copy of data
newdesc = copy.deepcopy(sdfg.arrays[dst.data])
newname = nsdfg.add_datadesc(dst.data,
newdesc,
find_new_name=True)
newaccess = nstate.add_access(newname)
# Redirect edges
xfh.redirect_edge(nstate,
rep_edge,
new_dst=newaccess,
new_data=newname)
xfh.redirect_edge(nstate,
edge,
new_src=newaccess,
new_data=newname)
# If has WCR, add warp-collaborative reduction on outputs
for out_edge in nstate.out_edges(inner_map_exit):
dst = nstate.memlet_path(out_edge)[-1].dst
if not xfh.contained_in(nstate, dst, new_me):
# Skip edges going out of map
continue
if dst.desc(nsdfg).storage == dtypes.StorageType.GPU_Global:
# Skip shared memory
continue
if out_edge.data.wcr is not None:
ctype = nsdfg.arrays[out_edge.data.data].dtype.ctype
redtype = detect_reduction_type(out_edge.data.wcr)
if redtype == dtypes.ReductionType.Custom:
raise NotImplementedError
credtype = ('dace::ReductionType::' +
str(redtype)[str(redtype).find('.') + 1:])
# One element: tasklet
if out_edge.data.subset.num_elements() == 1:
# Add local access between thread-local and warp reduction
name = nsdfg._find_new_name(out_edge.data.data)
nsdfg.add_scalar(
name,
nsdfg.arrays[out_edge.data.data].dtype,
transient=True)
# Initialize thread-local to global value
read = nstate.add_read(out_edge.data.data)
write = nstate.add_write(name)
edge = nstate.add_nedge(read, write,
copy.deepcopy(out_edge.data))
edge.data.wcr = None
xfh.state_fission(nsdfg,
SubgraphView(nstate, [read, write]))
newnode = nstate.add_access(name)
nstate.remove_edge(out_edge)
edge = nstate.add_edge(out_edge.src, out_edge.src_conn,
newnode, None,
copy.deepcopy(out_edge.data))
for e in nstate.memlet_path(edge):
e.data.data = name
e.data.subset = subsets.Range([(0, 0, 1)])
wrt = nstate.add_tasklet(
'warpreduce', {'__a'}, {'__out'},
f'__out = dace::warpReduce<{credtype}, {ctype}>::reduce(__a);',
dtypes.Language.CPP)
nstate.add_edge(newnode, None, wrt, '__a',
Memlet(name))
out_edge.data.wcr = None
nstate.add_edge(wrt, '__out', out_edge.dst, None,
out_edge.data)
else: # More than one element: mapped tasklet
# Could be a parallel summation
# TODO(later): Check if reduction
continue
# End of WCR to warp reduction
# Make nested SDFG out of new scope
xfh.nest_state_subgraph(sdfg, graph,
graph.scope_subgraph(new_me, False, False))
return new_me
