From 330ffcf3a8dc07a948f44fd6b007091f0b25eed1 Mon Sep 17 00:00:00 2001
From: Martin Bauer <martin.bauer@fau.de>
Date: Fri, 21 Apr 2017 13:34:52 +0200
Subject: [PATCH] Simpler OpenMP handling & OpenMP parallel boundaries
- periodic kernels not yet OpenMP parallel
---
cpu/kernelcreation.py | 30 +++++++++++++++++++++++++++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/cpu/kernelcreation.py b/cpu/kernelcreation.py
index 8ae94cbbf..dab631a97 100644
--- a/cpu/kernelcreation.py
+++ b/cpu/kernelcreation.py
@@ -126,7 +126,7 @@ def createIndexedKernel(listOfEquations, indexFields, functionName="kernel", typ
return ast
-def addOpenMP(astNode, schedule="static", numThreads=None):
+def addOpenMP(astNode, schedule="static", numThreads=True):
"""
Parallelizes the outer loop with OpenMP
@@ -134,13 +134,37 @@ def addOpenMP(astNode, schedule="static", numThreads=None):
:param schedule: OpenMP scheduling policy e.g. 'static' or 'dynamic'
:param numThreads: explicitly specify number of threads
"""
+ if not numThreads:
+ return
+
assert type(astNode) is ast.KernelFunction
body = astNode.body
- threadsClause = "" if numThreads is None else " num_threads(%s)" % (numThreads,)
+ threadsClause = "" if numThreads else " num_threads(%s)" % (numThreads,)
wrapperBlock = ast.PragmaBlock('#pragma omp parallel' + threadsClause, body.takeChildNodes())
body.append(wrapperBlock)
outerLoops = [l for l in body.atoms(ast.LoopOverCoordinate) if l.isOutermostLoop]
assert outerLoops, "No outer loop found"
assert len(outerLoops) <= 1, "More than one outer loop found. Which one should be parallelized?"
- outerLoops[0].prefixLines.append("#pragma omp for schedule(%s)" % (schedule,))
+ loopToParallelize = outerLoops[0]
+ try:
+ loopRange = int(loopToParallelize.stop - loopToParallelize.start)
+ except TypeError:
+ loopRange = None
+
+ if numThreads is None:
+ import multiprocessing
+ numThreads = multiprocessing.cpu_count()
+
+ if loopRange is not None and loopRange < numThreads:
+ containedLoops = [l for l in loopToParallelize.body.args if isinstance(l, LoopOverCoordinate)]
+ if len(containedLoops) == 1:
+ containedLoop = containedLoops[0]
+ try:
+ containedLoopRange = int(containedLoop.stop - containedLoop.start)
+ if containedLoopRange > loopRange:
+ loopToParallelize = containedLoop
+ except TypeError:
+ pass
+
+ loopToParallelize.prefixLines.append("#pragma omp for schedule(%s)" % (schedule,))
--
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