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authorRémi Verschelde <remi@verschelde.fr>2021-05-21 18:30:02 +0200
committerGitHub <noreply@github.com>2021-05-21 18:30:02 +0200
commit3ee034451a9349e7de26decc662afefd7ab8c460 (patch)
treea8bec3fbb06c2eaca05a075f5ffe2cdd2d94f04a /thirdparty/embree/common/algorithms/parallel_partition.h
parent8fa07eae145e1e37eb8708ce8c117188b58e3ecc (diff)
parent767e374dced69b45db0afb30ca2ccf0bbbeef672 (diff)
Merge pull request #48885 from JFonS/upgrade_embree
Upgrade Embree to the latest official release (3.13.0).
Diffstat (limited to 'thirdparty/embree/common/algorithms/parallel_partition.h')
-rw-r--r--thirdparty/embree/common/algorithms/parallel_partition.h283
1 files changed, 283 insertions, 0 deletions
diff --git a/thirdparty/embree/common/algorithms/parallel_partition.h b/thirdparty/embree/common/algorithms/parallel_partition.h
new file mode 100644
index 0000000000..a1cbdc8e04
--- /dev/null
+++ b/thirdparty/embree/common/algorithms/parallel_partition.h
@@ -0,0 +1,283 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "parallel_for.h"
+#include "../math/range.h"
+
+namespace embree
+{
+ /* serial partitioning */
+ template<typename T, typename V, typename IsLeft, typename Reduction_T>
+ __forceinline size_t serial_partitioning(T* array,
+ const size_t begin,
+ const size_t end,
+ V& leftReduction,
+ V& rightReduction,
+ const IsLeft& is_left,
+ const Reduction_T& reduction_t)
+ {
+ T* l = array + begin;
+ T* r = array + end - 1;
+
+ while(1)
+ {
+ /* *l < pivot */
+ while (likely(l <= r && is_left(*l) ))
+ {
+ //prefetchw(l+4); // FIXME: enable?
+ reduction_t(leftReduction,*l);
+ ++l;
+ }
+ /* *r >= pivot) */
+ while (likely(l <= r && !is_left(*r)))
+ {
+ //prefetchw(r-4); FIXME: enable?
+ reduction_t(rightReduction,*r);
+ --r;
+ }
+ if (r<l) break;
+
+ reduction_t(leftReduction ,*r);
+ reduction_t(rightReduction,*l);
+ xchg(*l,*r);
+ l++; r--;
+ }
+
+ return l - array;
+ }
+
+ template<typename T, typename V, typename Vi, typename IsLeft, typename Reduction_T, typename Reduction_V>
+ class __aligned(64) parallel_partition_task
+ {
+ ALIGNED_CLASS_(64);
+ private:
+
+ static const size_t MAX_TASKS = 64;
+
+ T* array;
+ size_t N;
+ const IsLeft& is_left;
+ const Reduction_T& reduction_t;
+ const Reduction_V& reduction_v;
+ const Vi& identity;
+
+ size_t numTasks;
+ __aligned(64) size_t counter_start[MAX_TASKS+1];
+ __aligned(64) size_t counter_left[MAX_TASKS+1];
+ __aligned(64) range<ssize_t> leftMisplacedRanges[MAX_TASKS];
+ __aligned(64) range<ssize_t> rightMisplacedRanges[MAX_TASKS];
+ __aligned(64) V leftReductions[MAX_TASKS];
+ __aligned(64) V rightReductions[MAX_TASKS];
+
+ public:
+
+ __forceinline parallel_partition_task(T* array,
+ const size_t N,
+ const Vi& identity,
+ const IsLeft& is_left,
+ const Reduction_T& reduction_t,
+ const Reduction_V& reduction_v,
+ const size_t BLOCK_SIZE)
+
+ : array(array), N(N), is_left(is_left), reduction_t(reduction_t), reduction_v(reduction_v), identity(identity),
+ numTasks(min((N+BLOCK_SIZE-1)/BLOCK_SIZE,min(TaskScheduler::threadCount(),MAX_TASKS))) {}
+
+ __forceinline const range<ssize_t>* findStartRange(size_t& index, const range<ssize_t>* const r, const size_t numRanges)
+ {
+ size_t i = 0;
+ while(index >= (size_t)r[i].size())
+ {
+ assert(i < numRanges);
+ index -= (size_t)r[i].size();
+ i++;
+ }
+ return &r[i];
+ }
+
+ __forceinline void swapItemsInMisplacedRanges(const size_t numLeftMisplacedRanges,
+ const size_t numRightMisplacedRanges,
+ const size_t startID,
+ const size_t endID)
+ {
+ size_t leftLocalIndex = startID;
+ size_t rightLocalIndex = startID;
+ const range<ssize_t>* l_range = findStartRange(leftLocalIndex,leftMisplacedRanges,numLeftMisplacedRanges);
+ const range<ssize_t>* r_range = findStartRange(rightLocalIndex,rightMisplacedRanges,numRightMisplacedRanges);
+
+ size_t l_left = l_range->size() - leftLocalIndex;
+ size_t r_left = r_range->size() - rightLocalIndex;
+ T *__restrict__ l = &array[l_range->begin() + leftLocalIndex];
+ T *__restrict__ r = &array[r_range->begin() + rightLocalIndex];
+ size_t size = endID - startID;
+ size_t items = min(size,min(l_left,r_left));
+
+ while (size)
+ {
+ if (unlikely(l_left == 0))
+ {
+ l_range++;
+ l_left = l_range->size();
+ l = &array[l_range->begin()];
+ items = min(size,min(l_left,r_left));
+ }
+
+ if (unlikely(r_left == 0))
+ {
+ r_range++;
+ r_left = r_range->size();
+ r = &array[r_range->begin()];
+ items = min(size,min(l_left,r_left));
+ }
+
+ size -= items;
+ l_left -= items;
+ r_left -= items;
+
+ while(items) {
+ items--;
+ xchg(*l++,*r++);
+ }
+ }
+ }
+
+ __forceinline size_t partition(V& leftReduction, V& rightReduction)
+ {
+ /* partition the individual ranges for each task */
+ parallel_for(numTasks,[&] (const size_t taskID) {
+ const size_t startID = (taskID+0)*N/numTasks;
+ const size_t endID = (taskID+1)*N/numTasks;
+ V local_left(identity);
+ V local_right(identity);
+ const size_t mid = serial_partitioning(array,startID,endID,local_left,local_right,is_left,reduction_t);
+ counter_start[taskID] = startID;
+ counter_left [taskID] = mid-startID;
+ leftReductions[taskID] = local_left;
+ rightReductions[taskID] = local_right;
+ });
+ counter_start[numTasks] = N;
+ counter_left[numTasks] = 0;
+
+ /* finalize the reductions */
+ for (size_t i=0; i<numTasks; i++) {
+ reduction_v(leftReduction,leftReductions[i]);
+ reduction_v(rightReduction,rightReductions[i]);
+ }
+
+ /* calculate mid point for partitioning */
+ size_t mid = counter_left[0];
+ for (size_t i=1; i<numTasks; i++)
+ mid += counter_left[i];
+ const range<ssize_t> globalLeft (0,mid);
+ const range<ssize_t> globalRight(mid,N);
+
+ /* calculate all left and right ranges that are on the wrong global side */
+ size_t numMisplacedRangesLeft = 0;
+ size_t numMisplacedRangesRight = 0;
+ size_t numMisplacedItemsLeft = 0;
+ size_t numMisplacedItemsRight = 0;
+
+ for (size_t i=0; i<numTasks; i++)
+ {
+ const range<ssize_t> left_range (counter_start[i], counter_start[i] + counter_left[i]);
+ const range<ssize_t> right_range(counter_start[i] + counter_left[i], counter_start[i+1]);
+ const range<ssize_t> left_misplaced = globalLeft. intersect(right_range);
+ const range<ssize_t> right_misplaced = globalRight.intersect(left_range);
+
+ if (!left_misplaced.empty())
+ {
+ numMisplacedItemsLeft += left_misplaced.size();
+ leftMisplacedRanges[numMisplacedRangesLeft++] = left_misplaced;
+ }
+
+ if (!right_misplaced.empty())
+ {
+ numMisplacedItemsRight += right_misplaced.size();
+ rightMisplacedRanges[numMisplacedRangesRight++] = right_misplaced;
+ }
+ }
+ assert( numMisplacedItemsLeft == numMisplacedItemsRight );
+
+ /* if no items are misplaced we are done */
+ if (numMisplacedItemsLeft == 0)
+ return mid;
+
+ /* otherwise we copy the items to the right place in parallel */
+ parallel_for(numTasks,[&] (const size_t taskID) {
+ const size_t startID = (taskID+0)*numMisplacedItemsLeft/numTasks;
+ const size_t endID = (taskID+1)*numMisplacedItemsLeft/numTasks;
+ swapItemsInMisplacedRanges(numMisplacedRangesLeft,numMisplacedRangesRight,startID,endID);
+ });
+
+ return mid;
+ }
+ };
+
+ template<typename T, typename V, typename Vi, typename IsLeft, typename Reduction_T, typename Reduction_V>
+ __noinline size_t parallel_partitioning(T* array,
+ const size_t begin,
+ const size_t end,
+ const Vi &identity,
+ V &leftReduction,
+ V &rightReduction,
+ const IsLeft& is_left,
+ const Reduction_T& reduction_t,
+ const Reduction_V& reduction_v,
+ size_t BLOCK_SIZE = 128)
+ {
+ /* fall back to single threaded partitioning for small N */
+ if (unlikely(end-begin < BLOCK_SIZE))
+ return serial_partitioning(array,begin,end,leftReduction,rightReduction,is_left,reduction_t);
+
+ /* otherwise use parallel code */
+ else {
+ typedef parallel_partition_task<T,V,Vi,IsLeft,Reduction_T,Reduction_V> partition_task;
+ std::unique_ptr<partition_task> p(new partition_task(&array[begin],end-begin,identity,is_left,reduction_t,reduction_v,BLOCK_SIZE));
+ return begin+p->partition(leftReduction,rightReduction);
+ }
+ }
+
+ template<typename T, typename V, typename Vi, typename IsLeft, typename Reduction_T, typename Reduction_V>
+ __noinline size_t parallel_partitioning(T* array,
+ const size_t begin,
+ const size_t end,
+ const Vi &identity,
+ V &leftReduction,
+ V &rightReduction,
+ const IsLeft& is_left,
+ const Reduction_T& reduction_t,
+ const Reduction_V& reduction_v,
+ size_t BLOCK_SIZE,
+ size_t PARALLEL_THRESHOLD)
+ {
+ /* fall back to single threaded partitioning for small N */
+ if (unlikely(end-begin < PARALLEL_THRESHOLD))
+ return serial_partitioning(array,begin,end,leftReduction,rightReduction,is_left,reduction_t);
+
+ /* otherwise use parallel code */
+ else {
+ typedef parallel_partition_task<T,V,Vi,IsLeft,Reduction_T,Reduction_V> partition_task;
+ std::unique_ptr<partition_task> p(new partition_task(&array[begin],end-begin,identity,is_left,reduction_t,reduction_v,BLOCK_SIZE));
+ return begin+p->partition(leftReduction,rightReduction);
+ }
+ }
+
+
+ template<typename T, typename IsLeft>
+ inline size_t parallel_partitioning(T* array,
+ const size_t begin,
+ const size_t end,
+ const IsLeft& is_left,
+ size_t BLOCK_SIZE = 128)
+ {
+ size_t leftReduction = 0;
+ size_t rightReduction = 0;
+ return parallel_partitioning(
+ array,begin,end,0,leftReduction,rightReduction,is_left,
+ [] (size_t& t,const T& ref) { },
+ [] (size_t& t0,size_t& t1) { },
+ BLOCK_SIZE);
+ }
+
+}