From b02329060fde472312b2ac0c38e78409cb7d1822 Mon Sep 17 00:00:00 2001
From: Matt Wala <wala1@illinois.edu>
Date: Fri, 7 Apr 2017 01:44:55 -0500
Subject: [PATCH] global_barrier_order: Try hard to avoid using
recursive_insn_dep_map().
---
loopy/kernel/__init__.py | 59 ++++++++++++++++++++++++++++++++--------
1 file changed, 48 insertions(+), 11 deletions(-)
diff --git a/loopy/kernel/__init__.py b/loopy/kernel/__init__.py
index a7b35869..895e32da 100644
--- a/loopy/kernel/__init__.py
+++ b/loopy/kernel/__init__.py
@@ -839,6 +839,11 @@ class LoopKernel(ImmutableRecordWithoutPickling):
unvisited = set(insn.id for insn in self.instructions)
+ def is_barrier(my_insn_id):
+ insn = self.id_to_insn[my_insn_id]
+ from loopy.kernel.instruction import BarrierInstruction
+ return isinstance(insn, BarrierInstruction) and insn.kind == "global"
+
while unvisited:
stack = [unvisited.pop()]
@@ -848,16 +853,13 @@ class LoopKernel(ImmutableRecordWithoutPickling):
if top in visiting:
visiting.remove(top)
- from loopy.kernel.instruction import BarrierInstruction
- insn = self.id_to_insn[top]
- if isinstance(insn, BarrierInstruction):
- if insn.kind == "global":
- barriers.append(top)
-
if top in visited:
stack.pop()
continue
+ if is_barrier(top):
+ barriers.append(top)
+
visited.add(top)
visiting.add(top)
@@ -866,12 +868,47 @@ class LoopKernel(ImmutableRecordWithoutPickling):
assert child not in visiting
stack.append(child)
+ if len(barriers) == 0:
+ return ()
+
# Ensure this is the only possible order.
- for prev_barrier, barrier in zip(barriers, barriers[1:]):
- if prev_barrier not in self.recursive_insn_dep_map()[barrier]:
- raise LoopyError(
- "Unordered global barriers detected: '%s', '%s'"
- % (barrier, prev_barrier))
+ #
+ # This is done by traversing back up the dependency chain starting with
+ # the last barrier. If we don't see all the barriers, we know there must
+ # be a break in the order.
+
+ stack = [barriers[-1]]
+ visiting.clear()
+ visited.clear()
+
+ seen_barriers = set()
+
+ while stack:
+ top = stack[-1]
+
+ if top in visiting:
+ visiting.remove(top)
+
+ if top in visited:
+ stack.pop()
+ continue
+
+ if is_barrier(top):
+ seen_barriers.add(top)
+ if len(seen_barriers) == len(barriers):
+ break
+
+ visited.add(top)
+ visiting.add(top)
+
+ for child in self.id_to_insn[top].depends_on:
+ # Check for no cycles.
+ stack.append(child)
+
+ if len(seen_barriers) < len(barriers):
+ raise LoopyError(
+ "Unordered global barrier sets detected: '%s', '%s'"
+ % (seen_barriers, set(barriers) - seen_barriers))
return tuple(barriers)
--
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