foundationdb/fdbserver/SkipList.cpp

/*
 * SkipList.cpp
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdint.h>
#include <memory.h>
#include <stdio.h>
#include <algorithm>
#include <numeric>
#include <string>
#include <vector>

/*
#ifdef __GNUG__
#include <smmintrin.h>
#endif
*/

#include "flow/Platform.h"
#include "fdbrpc/fdbrpc.h"
#include "fdbrpc/PerfMetric.h"
#include "fdbclient/FDBTypes.h"
#include "fdbclient/KeyRangeMap.h"
#include "fdbclient/SystemData.h"
#include "fdbserver/Knobs.h"

#define PARALLEL_THREAD_COUNT                                                                                          \
	0 // FIXME: When >1, program execution (e.g. random numbers) is/was nondeterministic.  Why?

using std::max;
using std::min;

static std::vector<PerfDoubleCounter*> skc;

static thread_local uint32_t g_seed = 0;

static inline int skfastrand() {
	g_seed = g_seed * 1664525L + 1013904223L;
	return g_seed;
}

void setAffinity(int proc);

class SlowConflictSet {
public:
	bool is_conflict(const VectorRef<KeyRangeRef>& readRanges, Version read_snapshot);
	void add(const VectorRef<KeyRangeRef>& clearRanges, const VectorRef<KeyValueRef>& setValues, Version now);
	void clear(Version now);

private:
	KeyRangeMap<Version> age;
};

bool SlowConflictSet::is_conflict(const VectorRef<KeyRangeRef>& readRanges, Version read_snapshot) {
	for (auto range = readRanges.begin(); range != readRanges.end(); ++range) {
		auto intersecting = age.intersectingRanges(*range);
		for (auto it = intersecting.begin(); it != intersecting.end(); ++it)
			if (it.value() > read_snapshot) return true;
	}
	return false;
}

void SlowConflictSet::clear(Version now) {
	age.insert(allKeys, now);
}

void SlowConflictSet::add(const VectorRef<KeyRangeRef>& clearRanges, const VectorRef<KeyValueRef>& setValues,
                          Version now) {
	for (auto c = clearRanges.begin(); c != clearRanges.end(); ++c) age.insert(*c, now);
	for (auto s = setValues.begin(); s != setValues.end(); ++s) age.insert(s->key, now);
}

PerfDoubleCounter g_buildTest("Build", skc), g_add("Add", skc), g_add_sort("A.Sort", skc),
    g_detectConflicts("Detect", skc), g_sort("D.Sort", skc), g_combine("D.Combine", skc),
    g_checkRead("D.CheckRead", skc), g_checkBatch("D.CheckIntraBatch", skc), g_merge("D.MergeWrite", skc),
    g_merge_launch("D.Merge.Launch", skc), g_merge_fork("D.Merge.Fork", skc),
    g_merge_start_var("D.Merge.StartVariance", skc), g_merge_end_var("D.Merge.EndVariance", skc),
    g_merge_run_var("D.Merge.RunVariance", skc), g_merge_run_shortest("D.Merge.ShortestRun", skc),
    g_merge_run_longest("D.Merge.LongestRun", skc), g_merge_run_total("D.Merge.TotalRun", skc),
    g_merge_join("D.Merge.Join", skc), g_removeBefore("D.RemoveBefore", skc);

static force_inline int compare(const StringRef& a, const StringRef& b) {
	int c = memcmp(a.begin(), b.begin(), min(a.size(), b.size()));
	if (c < 0) return -1;
	if (c > 0) return +1;
	if (a.size() < b.size()) return -1;
	if (a.size() == b.size()) return 0;
	return +1;
}

struct ReadConflictRange {
	StringRef begin, end;
	Version version;
	int transaction;
	ReadConflictRange(StringRef begin, StringRef end, Version version, int transaction)
	  : begin(begin), end(end), version(version), transaction(transaction) {}
	bool operator<(const ReadConflictRange& rhs) const { return compare(begin, rhs.begin) < 0; }
};

struct KeyInfo {
	StringRef key;
	int* pIndex;
	bool nextKey;
	bool begin;
	bool write;
	int transaction;

	KeyInfo(){};
	KeyInfo(StringRef key, bool nextKey, bool begin, bool write, int transaction, int* pIndex)
	  : key(key), nextKey(nextKey), begin(begin), write(write), transaction(transaction), pIndex(pIndex) {}
};

// returns true if done with string
force_inline bool getCharacter(const KeyInfo& ki, int character, int& outputCharacter) {
	// normal case
	if (character < ki.key.size()) {
		outputCharacter = 5 + ki.key.begin()[character];
		return false;
	}

	// nextKey append a zero
	if (ki.nextKey && character >= ki.key.size()) {
		if (character == ki.key.size()) {
			outputCharacter = 5; // extra '0' character
			return false;
		}
		character--;
	}

	// termination
	if (character == ki.key.size()) {
		outputCharacter = 0;
		return false;
	}

	if (character == ki.key.size() + 1) {
		// end/begin+read/write relative sorting
		outputCharacter = ki.begin * 2 + (ki.write ^ ki.begin);
		return false;
	}

	outputCharacter = 0;
	return true;
}

bool operator<(const KeyInfo& lhs, const KeyInfo& rhs) {
	int i = min(lhs.key.size(), rhs.key.size());
	int c = memcmp(lhs.key.begin(), rhs.key.begin(), i);
	if (c != 0) return c < 0;

	// SOMEDAY: This is probably not very fast.  Slows D.Sort by ~20% relative to previous (incorrect) version.

	bool lDone, rDone;
	int lc, rc;
	while (true) {
		lDone = getCharacter(lhs, i, lc);
		rDone = getCharacter(rhs, i, rc);
		if (lDone && rDone) return false; // equality
		if (lc < rc) return true;
		if (lc > rc) return false;
		i++;
	}
}

bool operator==(const KeyInfo& lhs, const KeyInfo& rhs) {
	return !(lhs < rhs || rhs < lhs);
}

void swapSort(std::vector<KeyInfo>& points, int a, int b) {
	if (points[b] < points[a]) {
		KeyInfo temp;
		temp = points[a];
		points[a] = points[b];
		points[b] = temp;
	}
}

void smallSort(std::vector<KeyInfo>& points, int start, int N) {
	for (int i = 1; i < N; i++)
		for (int j = i; j > 0; j -= 2) swapSort(points, start + j - 1, start + j);
	for (int i = N - 2; i > 0; i--)
		for (int j = i; j > 0; j -= 2) swapSort(points, start + j - 1, start + j);
}

struct SortTask {
	int begin;
	int size;
	int character;
	SortTask(int begin, int size, int character) : begin(begin), size(size), character(character) {}
};

void sortPoints(std::vector<KeyInfo>& points) {
	std::vector<SortTask> tasks;
	std::vector<KeyInfo> newPoints;
	std::vector<int> counts;

	tasks.emplace_back(0, points.size(), 0);

	while (tasks.size()) {
		SortTask st = tasks.back();
		tasks.pop_back();

		if (st.size < 10) {
			// smallSort(points, st.begin, st.size);
			std::sort(points.begin() + st.begin, points.begin() + st.begin + st.size);
			continue;
		}

		newPoints.resize(st.size);
		counts.assign(256 + 5, 0);

		// get counts
		int c;
		bool allDone = true;
		for (int i = st.begin; i < st.begin + st.size; i++) {
			allDone &= getCharacter(points[i], st.character, c);
			counts[c]++;
		}
		if (allDone) continue;

		// calculate offsets from counts and build next level of tasks
		int total = 0;
		for (int i = 0; i < counts.size(); i++) {
			int temp = counts[i];
			if (temp > 1) tasks.emplace_back(st.begin + total, temp, st.character + 1);
			counts[i] = total;
			total += temp;
		}

		// put in their places
		for (int i = st.begin; i < st.begin + st.size; i++) {
			getCharacter(points[i], st.character, c);
			newPoints[counts[c]++] = points[i];
		}

		// copy back into original points array
		for (int i = 0; i < st.size; i++) points[st.begin + i] = newPoints[i];
	}

	// cout << endl << "Radix sort done" << endl;
}

class SkipList : NonCopyable {
private:
	static const int MaxLevels = 26;

	int randomLevel() {
		/*int l = 0;
		while (deterministicRandom()->random01() < 0.5 && l < MaxLevels-1) l++;
		return l; */

		// deterministicRandom()->randomInt(0, 1<<(MaxLevels-1));
		uint32_t i = uint32_t(skfastrand()) >> (32 - (MaxLevels - 1));
		int level = 0;
		while (i & 1) {
			i >>= 1;
			level++;
		}
		ASSERT(level < MaxLevels);
		return level;
	}

	/*
	struct Node {
	    int nPointers, valueLength;
	    Node *pointers[nPointers];
	    Version maxVersions[nPointers];
	    char value[valueLength];
	};
	*/

	struct Node {
		int level() { return nPointers - 1; }
		uint8_t* value() { return end() + nPointers * (sizeof(Node*) + sizeof(Version)); }
		int length() { return valueLength; }
		Node* getNext(int i) { return *((Node**)end() + i); }
		void setNext(int i, Node* n) {
			*((Node**)end() + i) = n;
#if defined(_DEBUG) || 1
/*if (n && n->level() < i)
 *(volatile int*)0 = 0;*/
#endif
		}

		Version getMaxVersion(int i) { return ((Version*)(end() + nPointers * sizeof(Node*)))[i]; }
		void setMaxVersion(int i, Version v) { ((Version*)(end() + nPointers * sizeof(Node*)))[i] = v; }

		// Return a node with initialized value but uninitialized pointers
		static Node* create(const StringRef& value, int level) {
			int nodeSize = sizeof(Node) + value.size() + (level + 1) * (sizeof(Node*) + sizeof(Version));

			Node* n;
			if (nodeSize <= 64) {
				n = (Node*)FastAllocator<64>::allocate();
				INSTRUMENT_ALLOCATE("SkipListNode64");
			} else if (nodeSize <= 128) {
				n = (Node*)FastAllocator<128>::allocate();
				INSTRUMENT_ALLOCATE("SkipListNode128");
			} else {
				n = (Node*)new char[nodeSize];
				INSTRUMENT_ALLOCATE("SkipListNodeLarge");
			}

			n->nPointers = level + 1;

			n->valueLength = value.size();
			if (value.size() > 0) {
				memcpy(n->value(), value.begin(), value.size());
			}
			return n;
		}

		// pre: level>0, all lower level nodes between this and getNext(level) have correct maxversions
		void calcVersionForLevel(int level) {
			Node* end = getNext(level);
			Version v = getMaxVersion(level - 1);
			for (Node* x = getNext(level - 1); x != end; x = x->getNext(level - 1))
				v = max(v, x->getMaxVersion(level - 1));
			setMaxVersion(level, v);
		}

		void destroy() {
			int nodeSize = getNodeSize();
			if (nodeSize <= 64) {
				FastAllocator<64>::release(this);
				INSTRUMENT_RELEASE("SkipListNode64");
			} else if (nodeSize <= 128) {
				FastAllocator<128>::release(this);
				INSTRUMENT_RELEASE("SkipListNode128");
			} else {
				delete[](char*) this;
				INSTRUMENT_RELEASE("SkipListNodeLarge");
			}
		}

	private:
		int getNodeSize() { return sizeof(Node) + valueLength + nPointers * (sizeof(Node*) + sizeof(Version)); }
		uint8_t* end() { return (uint8_t*)(this + 1); }
		int nPointers, valueLength;
	};

	static force_inline bool less(const uint8_t* a, int aLen, const uint8_t* b, int bLen) {
		int len = min(aLen, bLen);
		for (int i = 0; i < len; i++)
			if (a[i] < b[i])
				return true;
			else if (a[i] > b[i])
				return false;

		/*int c = memcmp(a,b,min(aLen,bLen));
		if (c<0) return true;
		if (c>0) return false;*/
		return aLen < bLen;
	}

	Node* header;

	void destroy() {
		Node *next, *x;
		for (x = header; x; x = next) {
			next = x->getNext(0);
			x->destroy();
		}
	}

public:
	struct Finger {
		Node* finger[MaxLevels]; // valid for levels >= level
		int level;
		Node* x;
		Node* alreadyChecked;
		StringRef value;

		Finger() : level(MaxLevels), x(NULL), alreadyChecked(NULL) {}

		Finger(Node* header, const StringRef& ptr) : value(ptr), level(MaxLevels), alreadyChecked(NULL), x(header) {}

		void init(const StringRef& value, Node* header) {
			this->value = value;
			x = header;
			alreadyChecked = NULL;
			level = MaxLevels;
		}

		// pre: !finished()
		force_inline void prefetch() {
			Node* next = x->getNext(level - 1);
			_mm_prefetch((const char*)next, _MM_HINT_T0);
			// if ( (((intptr_t)next) & 64) == 0 )
			_mm_prefetch((const char*)next + 64, _MM_HINT_T0);
			//_mm_prefetch( (const char*)next+128, _MM_HINT_T0 );
			//_mm_prefetch( (const char*)next+192, _MM_HINT_T0 );
			//_mm_prefetch( (const char*)next+256, _MM_HINT_T0 );
			//_mm_prefetch( (const char*)next+320, _MM_HINT_T0 );
		}

		// pre: !finished()
		// Returns true if we have advanced to the next level
		force_inline bool advance() {
			Node* next = x->getNext(level - 1);

			if (next == alreadyChecked || !less(next->value(), next->length(), value.begin(), value.size())) {
				alreadyChecked = next;
				level--;
				finger[level] = x;
				return true;
			} else {
				x = next;
				return false;
			}
		}

		// pre: !finished()
		force_inline void nextLevel() {
			while (!advance())
				;
		}

		force_inline bool finished() { return level == 0; }

		force_inline Node* found() const {
			// valid after finished returns true
			Node* n = finger[0]->getNext(0); // or alreadyChecked, but that is more easily invalidated
			if (n && n->length() == value.size() && !memcmp(n->value(), value.begin(), value.size()))
				return n;
			else
				return NULL;
		}

		StringRef getValue() const {
			Node* n = finger[0]->getNext(0);
			return n ? StringRef(n->value(), n->length()) : StringRef();
		}
	};

	int count() {
		int count = 0;
		Node* x = header->getNext(0);
		while (x) {
			x = x->getNext(0);
			count++;
		}
		return count;
	}

	explicit SkipList(Version version = 0) {
		header = Node::create(StringRef(), MaxLevels - 1);
		for (int l = 0; l < MaxLevels; l++) {
			header->setNext(l, NULL);
			header->setMaxVersion(l, version);
		}
	}
	~SkipList() { destroy(); }
	SkipList(SkipList&& other) BOOST_NOEXCEPT : header(other.header) { other.header = NULL; }
	void operator=(SkipList&& other) BOOST_NOEXCEPT {
		destroy();
		header = other.header;
		other.header = NULL;
	}
	void swap(SkipList& other) { std::swap(header, other.header); }

	void addConflictRanges(const Finger* fingers, int rangeCount, Version version) {
		for (int r = rangeCount - 1; r >= 0; r--) {
			const Finger& startF = fingers[r * 2];
			const Finger& endF = fingers[r * 2 + 1];

			if (endF.found() == NULL) insert(endF, endF.finger[0]->getMaxVersion(0));

			remove(startF, endF);
			insert(startF, version);
		}
	}

	void detectConflicts(ReadConflictRange* ranges, int count, bool* transactionConflictStatus) {
		const int M = 16;
		int nextJob[M];
		CheckMax inProgress[M];
		if (!count) return;

		int started = min(M, count);
		for (int i = 0; i < started; i++) {
			inProgress[i].init(ranges[i], header, transactionConflictStatus);
			nextJob[i] = i + 1;
		}
		nextJob[started - 1] = 0;

		int prevJob = started - 1;
		int job = 0;
		// vtune: 340 parts
		while (true) {
			if (inProgress[job].advance()) {
				if (started == count) {
					if (prevJob == job) break;
					nextJob[prevJob] = nextJob[job];
					job = prevJob;
				} else
					inProgress[job].init(ranges[started++], header, transactionConflictStatus);
			}
			prevJob = job;
			job = nextJob[job];
		}
	}

	// Splits the version history represented by this skiplist into separate key ranges
	//   delimited by the given array of keys.  This SkipList is left empty.  this->partition
	//   is intended to be followed by a call to this->concatenate() recombining the same
	//   partitions.  In between, operations on each partition must not touch any keys outside
	//   the partition.  Specifically, the partition to the left of 'key' must not have a range
	//	 [...,key) inserted, since that would insert an entry at 'key'.
	void partition(StringRef* begin, int splitCount, SkipList* output) {
		for (int i = splitCount - 1; i >= 0; i--) {
			Finger f(header, begin[i]);
			while (!f.finished()) f.nextLevel();
			split(f, output[i + 1]);
		}
		swap(output[0]);
	}

	void concatenate(SkipList* input, int count) {
		std::vector<Finger> ends(count - 1);
		for (int i = 0; i < ends.size(); i++) input[i].getEnd(ends[i]);

		for (int l = 0; l < MaxLevels; l++) {
			for (int i = ends.size() - 1; i >= 0; i--) {
				ends[i].finger[l]->setNext(l, input[i + 1].header->getNext(l));
				if (l && (!i || ends[i].finger[l] != input[i].header)) ends[i].finger[l]->calcVersionForLevel(l);
				input[i + 1].header->setNext(l, NULL);
			}
		}
		swap(input[0]);
	}

	void find(const StringRef* values, Finger* results, int* temp, int count) {
		// Relying on the ordering of values, descend until the values aren't all in the
		// same part of the tree

		// vtune: 11 parts
		results[0].init(values[0], header);
		const StringRef& endValue = values[count - 1];
		while (results[0].level > 1) {
			results[0].nextLevel();
			Node* ac = results[0].alreadyChecked;
			if (ac && less(ac->value(), ac->length(), endValue.begin(), endValue.size())) break;
		}

		// Init all the other fingers to start descending where we stopped
		//   the first one

		// SOMEDAY: this loop showed up on vtune, could be faster?
		// vtune: 8 parts
		int startLevel = results[0].level + 1;
		Node* x = startLevel < MaxLevels ? results[0].finger[startLevel] : header;
		for (int i = 1; i < count; i++) {
			results[i].level = startLevel;
			results[i].x = x;
			results[i].alreadyChecked = NULL;
			results[i].value = values[i];
			for (int j = startLevel; j < MaxLevels; j++) results[i].finger[j] = results[0].finger[j];
		}

		int* nextJob = temp;
		for (int i = 0; i < count - 1; i++) nextJob[i] = i + 1;
		nextJob[count - 1] = 0;

		int prevJob = count - 1;
		int job = 0;

		// vtune: 225 parts
		while (true) {
			Finger* f = &results[job];
			f->advance();
			if (f->finished()) {
				if (prevJob == job) break;
				nextJob[prevJob] = nextJob[job];
			} else {
				f->prefetch();
				prevJob = job;
			}
			job = nextJob[job];
		}
	}

	/*Finger randomFinger() {
	    // Written, not exactly uniform, not tested
	    Finger f( header, StringRef() );
	    Node* begin = header, *end = 0;
	    for(int lev = MaxLevels-1; lev>=0; lev--) {
	        int length = 0;
	        for( Node* x = begin; x != end; x=x->getNext(lev) )
	            length++;
	        if (length == 1) { // forced down
	            f.finger[lev] = begin;
	        } else {
	            int c = deterministicRandom()->randomInt(0, length);
	            for( Node* x = begin; x != end; x=x->getNext(lev) )
	                if (!c--) {
	                    f.finger[lev] = begin = x;
	                    end = x->getNext(lev);
	                    break;
	                }
	        }
	    }
	    f.level = 0;
	    return f;
	}*/

	int removeBefore(Version v, Finger& f, int nodeCount) {
		/*Finger f( header, StringRef() );
		for(int i=0; i<MaxLevels; i++)
		    f.finger[i] = header;
		f.level = 0;*/
		// f.x, f.alreadyChecked?

		int removedCount = 0;
		bool wasAbove = true;
		while (nodeCount--) {
			Node* x = f.finger[0]->getNext(0);
			if (!x) break;

			// double prefetch gives +25% speed (single threaded)
			Node* next = x->getNext(0);
			_mm_prefetch((const char*)next, _MM_HINT_T0);
			//_mm_prefetch( (const char*)next+64, _MM_HINT_T0 );
			next = x->getNext(1);
			_mm_prefetch((const char*)next, _MM_HINT_T0);
			//_mm_prefetch( (const char*)next+64, _MM_HINT_T0 );

			bool isAbove = x->getMaxVersion(0) >= v;
			if (isAbove || wasAbove) { // f.nextItem
				for (int l = 0; l <= x->level(); l++) f.finger[l] = x;
			} else { // f.eraseItem
				removedCount++;
				for (int l = 0; l <= x->level(); l++) f.finger[l]->setNext(l, x->getNext(l));
				for (int i = 1; i <= x->level(); i++)
					f.finger[i]->setMaxVersion(i, max(f.finger[i]->getMaxVersion(i), x->getMaxVersion(i)));
				x->destroy();
			}
			wasAbove = isAbove;
		}

		return removedCount;
	}

private:
	void remove(const Finger& start, const Finger& end) {
		if (start.finger[0] == end.finger[0]) return;

		Node* x = start.finger[0]->getNext(0);

		// vtune says: this loop is the expensive parts (6 parts)
		for (int i = 0; i < MaxLevels; i++)
			if (start.finger[i] != end.finger[i]) start.finger[i]->setNext(i, end.finger[i]->getNext(i));

		while (true) {
			Node* next = x->getNext(0);
			x->destroy();
			if (x == end.finger[0]) break;
			x = next;
		}
	}

	// void insert( const std::string& v, Version version ) { insert(StringRef(v), version); }

	void insert(const Finger& f, Version version) {
		int level = randomLevel();
		// cout << std::string((const char*)value,length) << " level: " << level << endl;
		Node* x = Node::create(f.value, level);
		x->setMaxVersion(0, version);
		for (int i = 0; i <= level; i++) {
			x->setNext(i, f.finger[i]->getNext(i));
			f.finger[i]->setNext(i, x);
		}
		// vtune says: this loop is the costly part of this function
		for (int i = 1; i <= level; i++) {
			f.finger[i]->calcVersionForLevel(i);
			x->calcVersionForLevel(i);
		}
		for (int i = level + 1; i < MaxLevels; i++) {
			Version v = f.finger[i]->getMaxVersion(i);
			if (v >= version) break;
			f.finger[i]->setMaxVersion(i, version);
		}
	}

	void insert(const StringRef& value, Version version) {
		Finger f(header, value);
		while (!f.finished()) f.nextLevel();
		// SOMEDAY: equality?
		insert(f, version);
	}

	struct CheckMax {
		Finger start, end;
		Version version;
		bool* result;
		int state;

		void init(const ReadConflictRange& r, Node* header, bool* tCS) {
			this->start.init(r.begin, header);
			this->end.init(r.end, header);
			this->version = r.version;
			result = &tCS[r.transaction];
			this->state = 0;
		}

		bool noConflict() { return true; }
		bool conflict() {
			*result = true;
			return true;
		}

		// Return true if finished
		force_inline bool advance() {
			switch (state) {
			case 0:
				// find where start and end fingers diverge
				while (true) {
					if (!start.advance()) {
						start.prefetch();
						return false;
					}
					end.x = start.x;
					while (!end.advance())
						;

					int l = start.level;
					if (start.finger[l] != end.finger[l]) break;
					// accept if the range spans the check range, but does not have a greater version
					if (start.finger[l]->getMaxVersion(l) <= version) return noConflict();
					if (l == 0) return conflict();
				}
				state = 1;
			case 1: {
				// check the end side of the pyramid
				Node* e = end.finger[end.level];
				while (e->getMaxVersion(end.level) > version) {
					if (end.finished()) return conflict();
					end.nextLevel();
					Node* f = end.finger[end.level];
					while (e != f) {
						if (e->getMaxVersion(end.level) > version) return conflict();
						e = e->getNext(end.level);
					}
				}

				// check the start side of the pyramid
				Node* s = end.finger[start.level];
				while (true) {
					Node* nextS = start.finger[start.level]->getNext(start.level);
					Node* p = nextS;
					while (p != s) {
						if (p->getMaxVersion(start.level) > version) return conflict();
						p = p->getNext(start.level);
					}
					if (start.finger[start.level]->getMaxVersion(start.level) <= version) return noConflict();
					s = nextS;
					if (start.finished()) {
						if (nextS->length() == start.value.size() &&
						    !memcmp(nextS->value(), start.value.begin(), start.value.size()))
							return noConflict();
						else
							return conflict();
					}
					start.nextLevel();
				}
			}
			default:
				__assume(false);
			}
		}
	};

	void split(const Finger& f, SkipList& right) {
		ASSERT(!right.header->getNext(0)); // right must be empty
		right.header->setMaxVersion(0, f.finger[0]->getMaxVersion(0));
		for (int l = 0; l < MaxLevels; l++) {
			right.header->setNext(l, f.finger[l]->getNext(l));
			f.finger[l]->setNext(l, NULL);
			/*if (l) {
			    // SOMEDAY: Do we actually need these?
			    right.header->calcVersionForLevel(l);
			    f.finger[l]->calcVersionForLevel(l);
			}*/
		}
	}

	void getEnd(Finger& end) {
		Node* node = header;
		for (int l = MaxLevels - 1; l >= 0; l--) {
			Node* next;
			while ((next = node->getNext(l)) != NULL) node = next;
			end.finger[l] = node;
		}
		end.level = 0;
		// SOMEDAY: end.x? end.alreadyChecked?
		/*end = Finger(header, (const uint8_t*)"\xff\xff\xff\xff\xff\xff", 6);
		while (!end.finished())
		    end.nextLevel();*/
	}
};

struct Action {
	virtual void operator()() = 0; // self-destructs
};
typedef Action* PAction;

template <class F>
PAction action(F&& f) {
	struct FAction : Action, F, FastAllocated<FAction> {
		FAction(F&& f) : F(std::move(f)) {}
		virtual void operator()() {
			F::operator()();
			delete this;
		}
	};
	return new FAction(std::move(f));
};

void workerThread(PAction* nextAction, Event* nextActionReady, int index, Event* whenFinished) {
	ASSERT(false);
	/*
	inThread<Void>( [nextAction,nextActionReady,index,whenFinished]()->Void {
	    g_seed = index*123; fastrand();
	    setAffinity( index );
	    while (true) {
	        try {
	            nextActionReady->block();   // auto-reset
	            Action* action = *nextAction;
	            *nextAction = 0;
	            if (!action) break;

	            (*action)();
	        } catch (Error& e) {
	            fprintf(stderr, "Error in worker thread: %s\n", e.what());
	        } catch (...) {
	            fprintf(stderr, "Error in worker thread: %s\n", unknown_error().what());
	        }
	    }
	    //cout << "Worker thread finished" << endl;
	    whenFinished->set();
	    return Void();
	});*/
}

StringRef setK(Arena& arena, int i) {
	char t[sizeof(i)];
	*(int*)t = i;

	const int keySize = 16;

	char* ss = new (arena) char[keySize];
	for (int c = 0; c < keySize - sizeof(i); c++) ss[c] = '.';
	for (int c = 0; c < sizeof(i); c++) ss[c + keySize - sizeof(i)] = t[sizeof(i) - 1 - c];

	return StringRef((const uint8_t*)ss, keySize);
}

#include "fdbserver/ConflictSet.h"

struct ConflictSet {
	ConflictSet() : oldestVersion(0) {
		static_assert(PARALLEL_THREAD_COUNT == 0, "workerThread() not implemented");
		static_assert(PARALLEL_THREAD_COUNT == 0 || FASTALLOC_THREAD_SAFE,
		              "Thread safe fast allocator required for multithreaded conflict set");
		for (int i = 0; i < PARALLEL_THREAD_COUNT; i++) {
			worker_nextAction.push_back(NULL);
			worker_ready.push_back(new Event);
			worker_finished.push_back(new Event);
		}
		for (int t = 0; t < worker_nextAction.size(); t++)
			workerThread(&worker_nextAction[t], worker_ready[t], (t)*2, worker_finished[t]);
	}
	~ConflictSet() {
		for (int i = 0; i < worker_nextAction.size(); i++) {
			worker_nextAction[i] = 0;
			worker_ready[i]->set();
		}
		// Wait for workers to terminate; otherwise can get crashes at shutdown time
		for (int i = 0; i < worker_finished.size(); i++) worker_finished[i]->block();
	}

	SkipList versionHistory;
	Key removalKey;
	Version oldestVersion;
	std::vector<PAction> worker_nextAction;
	std::vector<Event*> worker_ready;
	std::vector<Event*> worker_finished;
};

ConflictSet* newConflictSet() {
	return new ConflictSet;
}
void clearConflictSet(ConflictSet* cs, Version v) {
	SkipList(v).swap(cs->versionHistory);
}
void destroyConflictSet(ConflictSet* cs) {
	delete cs;
}

ConflictBatch::ConflictBatch(ConflictSet* cs) : cs(cs), transactionCount(0) {}

ConflictBatch::~ConflictBatch() {}

struct TransactionInfo {
	VectorRef<std::pair<int, int>> readRanges;
	VectorRef<std::pair<int, int>> writeRanges;
	bool tooOld;
};

void ConflictBatch::addTransaction(const CommitTransactionRef& tr) {
	int t = transactionCount++;

	Arena& arena = transactionInfo.arena();
	TransactionInfo* info = new (arena) TransactionInfo;

	if (tr.read_snapshot < cs->oldestVersion && tr.read_conflict_ranges.size()) {
		info->tooOld = true;
	} else {
		info->tooOld = false;
		info->readRanges.resize(arena, tr.read_conflict_ranges.size());
		info->writeRanges.resize(arena, tr.write_conflict_ranges.size());

		std::vector<KeyInfo>& points = this->points;
		for (int r = 0; r < tr.read_conflict_ranges.size(); r++) {
			const KeyRangeRef& range = tr.read_conflict_ranges[r];
			points.emplace_back(range.begin, false, true, false, t, &info->readRanges[r].first);
			// points.back().keyEnd = StringRef(buf,range.second);
			points.emplace_back(range.end, false, false, false, t, &info->readRanges[r].second);
			combinedReadConflictRanges.emplace_back(range.begin, range.end, tr.read_snapshot, t);
		}
		for (int r = 0; r < tr.write_conflict_ranges.size(); r++) {
			const KeyRangeRef& range = tr.write_conflict_ranges[r];
			points.emplace_back(range.begin, false, true, true, t, &info->writeRanges[r].first);
			points.emplace_back(range.end, false, false, true, t, &info->writeRanges[r].second);
		}
	}

	this->transactionInfo.push_back(arena, info);
}

class MiniConflictSet2 : NonCopyable {
	std::vector<bool> values;

public:
	explicit MiniConflictSet2(int size) { values.assign(size, false); }
	void set(int begin, int end) {
		for (int i = begin; i < end; i++) values[i] = true;
	}
	bool any(int begin, int end) {
		for (int i = begin; i < end; i++)
			if (values[i]) return true;
		return false;
	}
};

class MiniConflictSet : NonCopyable {
	typedef uint64_t wordType;
	enum { bucketShift = 6, bucketMask = sizeof(wordType) * 8 - 1 };
	std::vector<wordType> values; // undefined when andValues is true for a range of values
	std::vector<wordType> orValues;
	std::vector<wordType> andValues;
	MiniConflictSet2 debug; // SOMEDAY: Test on big ranges, eliminate this

	wordType bitMask(unsigned int bit) { // computes results for bit%word
		return (((wordType)1) << (bit & bucketMask));
	}
	void setNthBit(std::vector<wordType>& v, const unsigned int bit) { v[bit >> bucketShift] |= bitMask(bit); }
	void clearNthBit(std::vector<wordType>& v, const unsigned int bit) { v[bit >> bucketShift] &= ~(bitMask(bit)); }
	bool getNthBit(const std::vector<wordType>& v, const unsigned int bit) {
		return (v[bit >> bucketShift] & bitMask(bit)) != 0;
	}
	int wordsForNBits(unsigned int bits) { return (bits + ((1 << bucketShift) - 1)) >> bucketShift; }
	wordType highBits(int b) { // bits (b&bucketMask) and higher are 1
#pragma warning(disable : 4146)
		return -bitMask(b);
#pragma warning(default : 4146)
	}
	wordType lowBits(int b) { // bits lower than (b&bucketMask) are 1
		return bitMask(b) - 1;
	}
	wordType lowBits2(int b) { return (b & bucketMask) ? lowBits(b) : -1; }

	void setBits(std::vector<wordType>& v, int bitBegin, int bitEnd, bool fillMiddle) {
		if (bitBegin >= bitEnd) return;
		int beginWord = bitBegin >> bucketShift;
		int lastWord = ((bitEnd + bucketMask) >> bucketShift) - 1;
		if (beginWord == lastWord) {
			v[beginWord] |= highBits(bitBegin) & lowBits2(bitEnd);
		} else {
			v[beginWord] |= highBits(bitBegin);
			if (fillMiddle)
				for (int w = beginWord + 1; w < lastWord; w++) v[w] = wordType(-1);
			v[lastWord] |= lowBits2(bitEnd);
		}
	}

	bool orBits(std::vector<wordType>& v, int bitBegin, int bitEnd, bool getMiddle) {
		if (bitBegin >= bitEnd) return false;
		int beginWord = bitBegin >> bucketShift;
		int lastWord = ((bitEnd + bucketMask) >> bucketShift) - 1;
		if (beginWord == lastWord)
			return (v[beginWord] & highBits(bitBegin) & lowBits2(bitEnd)) != 0;
		else {
			if (getMiddle)
				for (int w = beginWord + 1; w < lastWord; w++)
					if (v[w]) return true;
			return ((v[beginWord] & highBits(bitBegin)) | (v[lastWord] & lowBits2(bitEnd))) != 0;
		}
	}

	bool orImpl(int begin, int end) {
		if (begin == end) return false;
		int beginWord = begin >> bucketShift;
		int lastWord = ((end + bucketMask) >> bucketShift) - 1;

		return orBits(orValues, beginWord + 1, lastWord, true) || getNthBit(andValues, beginWord) ||
		       getNthBit(andValues, lastWord) || orBits(values, begin, end, false);
	}

public:
	explicit MiniConflictSet(int size) : debug(size) {
		static_assert((1 << bucketShift) == sizeof(wordType) * 8, "BucketShift incorrect");

		values.assign(wordsForNBits(size), false);
		orValues.assign(wordsForNBits(wordsForNBits(size)), false);
		andValues.assign(wordsForNBits(wordsForNBits(size)), false);
	}

	void set(int begin, int end) {
		debug.set(begin, end);
		if (begin == end) return;

		int beginWord = begin >> bucketShift;
		int lastWord = ((end + bucketMask) >> bucketShift) - 1;

		setBits(values, begin, end, false);
		setBits(andValues, beginWord + 1, lastWord, true);
		setBits(orValues, beginWord, lastWord + 1, true);
	}

	bool any(int begin, int end) {
		bool a = orImpl(begin, end);
		bool b = debug.any(begin, end);
		ASSERT(a == b);
		return b;
	}
};

void ConflictBatch::checkIntraBatchConflicts() {
	int index = 0;
	for (int p = 0; p < points.size(); p++) *points[p].pIndex = index++;

	MiniConflictSet mcs(index);
	for (int t = 0; t < transactionInfo.size(); t++) {
		const TransactionInfo& tr = *transactionInfo[t];
		if (transactionConflictStatus[t]) continue;
		bool conflict = tr.tooOld;
		for (int i = 0; i < tr.readRanges.size(); i++)
			if (mcs.any(tr.readRanges[i].first, tr.readRanges[i].second)) {
				conflict = true;
				break;
			}
		transactionConflictStatus[t] = conflict;
		if (!conflict)
			for (int i = 0; i < tr.writeRanges.size(); i++) mcs.set(tr.writeRanges[i].first, tr.writeRanges[i].second);
	}
}

void ConflictBatch::GetTooOldTransactions(std::vector<int>& tooOldTransactions) {
	for (int i = 0; i < transactionInfo.size(); i++) {
		if (transactionInfo[i]->tooOld) {
			tooOldTransactions.push_back(i);
		}
	}
}

void ConflictBatch::detectConflicts(Version now, Version newOldestVersion, std::vector<int>& nonConflicting,
                                    std::vector<int>* tooOldTransactions) {
	double t = timer();
	sortPoints(points);
	// std::sort( combinedReadConflictRanges.begin(), combinedReadConflictRanges.end() );
	g_sort += timer() - t;

	transactionConflictStatus = new bool[transactionCount];
	memset(transactionConflictStatus, 0, transactionCount * sizeof(bool));

	t = timer();
	checkReadConflictRanges();
	g_checkRead += timer() - t;

	t = timer();
	checkIntraBatchConflicts();
	g_checkBatch += timer() - t;

	t = timer();
	combineWriteConflictRanges();
	g_combine += timer() - t;

	t = timer();
	mergeWriteConflictRanges(now);
	g_merge += timer() - t;

	for (int i = 0; i < transactionCount; i++) {
		if (!transactionConflictStatus[i]) nonConflicting.push_back(i);
		if (tooOldTransactions && transactionInfo[i]->tooOld) tooOldTransactions->push_back(i);
	}

	delete[] transactionConflictStatus;

	t = timer();
	if (newOldestVersion > cs->oldestVersion) {
		cs->oldestVersion = newOldestVersion;
		SkipList::Finger finger;
		int temp;
		cs->versionHistory.find(&cs->removalKey, &finger, &temp, 1);
		cs->versionHistory.removeBefore(cs->oldestVersion, finger, combinedWriteConflictRanges.size() * 3 + 10);
		cs->removalKey = finger.getValue();
	}
	g_removeBefore += timer() - t;
}

void ConflictBatch::checkReadConflictRanges() {
	if (!combinedReadConflictRanges.size()) return;

	if (PARALLEL_THREAD_COUNT) {
		Event done[PARALLEL_THREAD_COUNT ? PARALLEL_THREAD_COUNT : 1];
		for (int t = 0; t < PARALLEL_THREAD_COUNT; t++) {
			cs->worker_nextAction[t] = action([&, t] {
#pragma GCC diagnostic push
				DISABLE_ZERO_DIVISION_FLAG
				auto begin =
				    &combinedReadConflictRanges[0] + t * combinedReadConflictRanges.size() / PARALLEL_THREAD_COUNT;
				auto end = &combinedReadConflictRanges[0] +
				           (t + 1) * combinedReadConflictRanges.size() / PARALLEL_THREAD_COUNT;
#pragma GCC diagnostic pop
				cs->versionHistory.detectConflicts(begin, end - begin, transactionConflictStatus);
				done[t].set();
			});
			cs->worker_ready[t]->set();
		}
		for (int i = 0; i < PARALLEL_THREAD_COUNT; i++) done[i].block();
	} else {
		cs->versionHistory.detectConflicts(&combinedReadConflictRanges[0], combinedReadConflictRanges.size(),
		                                   transactionConflictStatus);
	}
}

void ConflictBatch::addConflictRanges(Version now, std::vector<std::pair<StringRef, StringRef>>::iterator begin,
                                      std::vector<std::pair<StringRef, StringRef>>::iterator end, SkipList* part) {
	int count = end - begin;
#if 0
	//for(auto w = begin; w != end; ++w)
	for(auto w = end-1; w != begin-1; --w)
		part->addConflictRange( w->first, w->second, now );
#else
	static_assert(sizeof(begin[0]) == sizeof(StringRef) * 2,
	              "Write Conflict Range type not convertible to two StringPtrs");
	const StringRef* strings = reinterpret_cast<const StringRef*>(&*begin);
	int stringCount = count * 2;

	static const int stripeSize = 16;
	SkipList::Finger fingers[stripeSize];
	int temp[stripeSize];
	int stripes = (stringCount + stripeSize - 1) / stripeSize;

	int ss = stringCount - (stripes - 1) * stripeSize;
	for (int s = stripes - 1; s >= 0; s--) {
		part->find(&strings[s * stripeSize], &fingers[0], temp, ss);
		part->addConflictRanges(&fingers[0], ss / 2, now);
		ss = stripeSize;
	}
#endif
}

void ConflictBatch::mergeWriteConflictRanges(Version now) {
	if (!combinedWriteConflictRanges.size()) return;

	if (PARALLEL_THREAD_COUNT) {
		std::vector<SkipList> parts;
		for (int i = 0; i < PARALLEL_THREAD_COUNT; i++) parts.emplace_back();

		std::vector<StringRef> splits(parts.size() - 1);
		for (int s = 0; s < splits.size(); s++)
			splits[s] = combinedWriteConflictRanges[(s + 1) * combinedWriteConflictRanges.size() / parts.size()].first;

		cs->versionHistory.partition(splits.size() ? &splits[0] : NULL, splits.size(), &parts[0]);
		std::vector<double> tstart(PARALLEL_THREAD_COUNT), tend(PARALLEL_THREAD_COUNT);
		Event done[PARALLEL_THREAD_COUNT ? PARALLEL_THREAD_COUNT : 1];
		double before = timer();
		for (int t = 0; t < parts.size(); t++) {
			cs->worker_nextAction[t] = action([&, t] {
				tstart[t] = timer();
				auto begin =
				    combinedWriteConflictRanges.begin() + (t * combinedWriteConflictRanges.size() / parts.size());
				auto end =
				    combinedWriteConflictRanges.begin() + ((t + 1) * combinedWriteConflictRanges.size() / parts.size());

				addConflictRanges(now, begin, end, &parts[t]);

				tend[t] = timer();
				done[t].set();
			});
			cs->worker_ready[t]->set();
		}
		double launch = timer();
		for (int i = 0; i < PARALLEL_THREAD_COUNT; i++) done[i].block();
		double after = timer();

		g_merge_launch += launch - before;
		// g_merge_start_var += *std::max_element(tstart.begin(), tstart.end()) - before;
		g_merge_fork += *std::min_element(tstart.begin(), tstart.end()) - before;
		g_merge_start_var +=
		    *std::max_element(tstart.begin(), tstart.end()) - *std::min_element(tstart.begin(), tstart.end());
		g_merge_end_var += *std::max_element(tend.begin(), tend.end()) - *std::min_element(tend.begin(), tend.end());
		g_merge_join += after - *std::max_element(tend.begin(), tend.end());
		double run_max = 0, run_min = 1e9;
		for (int i = 0; i < tend.size(); i++) {
			run_max = max(run_max, tend[i] - tstart[i]);
			run_min = min(run_min, tend[i] - tstart[i]);
		}
		g_merge_run_var += run_max - run_min;
		g_merge_run_shortest += run_min;
		g_merge_run_longest += run_max;
		g_merge_run_total +=
		    std::accumulate(tend.begin(), tend.end(), 0.0) - std::accumulate(tstart.begin(), tstart.end(), 0.0);

		cs->versionHistory.concatenate(&parts[0], parts.size());
	} else {
		addConflictRanges(now, combinedWriteConflictRanges.begin(), combinedWriteConflictRanges.end(),
		                  &cs->versionHistory);
	}

	// for(auto w = combinedWriteConflictRanges.begin(); w != combinedWriteConflictRanges.end(); ++w)
	//	versionHistory.addConflictRange( w->first.begin(), w->first.size(), w->second.begin(), w->second.size(), now );
}

void ConflictBatch::combineWriteConflictRanges() {
	int activeWriteCount = 0;
	for (int i = 0; i < points.size(); i++) {
		KeyInfo& point = points[i];
		if (point.write && !transactionConflictStatus[point.transaction]) {
			if (point.begin) {
				activeWriteCount++;
				if (activeWriteCount == 1) combinedWriteConflictRanges.emplace_back(point.key, KeyRef());
			} else /*if (point.end)*/ {
				activeWriteCount--;
				if (activeWriteCount == 0) combinedWriteConflictRanges.back().second = point.key;
			}
		}
	}
}

// void showNumaStatus();

/*
bool sse4Less( const uint8_t* a, int aLen, const uint8_t* b, int bLen ) {
    while (true) {
        int res = _mm_cmpestri(*(__m128i*)a, aLen, *(__m128i*)b, bLen, _SIDD_UBYTE_OPS | _SIDD_CMP_EQUAL_EACH |
_SIDD_NEGATIVE_POLARITY | _SIDD_LEAST_SIGNIFICANT ); printf("%d ", res); if (res == 16) { if (bLen < 16) return false;
            a += 16; b += 16; aLen -= 16; bLen -= 16;
        }
        if (res == bLen) return false;
        if (res == aLen) return true;

        return a[res] < b[res];
    }
}

void tless( const char* a, const char* b ) {
    bool x = sse4Less( (const uint8_t*)a, strlen(a), (const uint8_t*)b, strlen(b) );
    if (x)
        printf("%s < %s\n", a, b);
    else
        printf("%s >= %s\n", a, b);
}

void sse4Test(){

    tless("hello", "world");
    tless("a", "a");
    tless("world", "hello");
    tless("world", "worry");
    tless("worry", "world");
    tless("hello", "hello1");
    tless("hello1", "hello");

    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworld");
    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworld", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello");
    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworld", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworry");
    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworry", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaworld");
    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello1");
    tless("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello1", "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahello");

    char *a = "hello1worldthisisalonglonglongstring";
    char *b = "hello";
    __m128i aa = *(__m128i*)a;
    __m128i bb = *(__m128i*)a;

    int res = _mm_cmpestri(aa, 2, bb, 2, _SIDD_UBYTE_OPS | _SIDD_CMP_EQUAL_EACH | _SIDD_NEGATIVE_POLARITY |
_SIDD_LEAST_SIGNIFICANT );

    cout << res << endl;

}
*/

void miniConflictSetTest() {
	for (int i = 0; i < 2000000; i++) {
		int size = 64 * 5; // Also run 64*64*5 to test multiple words of andValues and orValues
		MiniConflictSet mini(size);
		for (int j = 0; j < 2; j++) {
			int a = deterministicRandom()->randomInt(0, size);
			int b = deterministicRandom()->randomInt(a, size);
			mini.set(a, b);
		}
		for (int j = 0; j < 4; j++) {
			int a = deterministicRandom()->randomInt(0, size);
			int b = deterministicRandom()->randomInt(a, size);
			mini.any(a, b); // Tests correctness internally
		}
	}
	printf("miniConflictSetTest complete\n");
}

void skipListTest() {
	printf("Skip list test\n");

	// sse4Test();

	// A test case that breaks the old operator<
	// KeyInfo a( LiteralStringRef("hello"), true, false, true, -1 );
	// KeyInfo b( LiteralStringRef("hello\0"), false, false, false, 0 );

	miniConflictSetTest();

	setAffinity(0);
	// showNumaStatus();

	double start;

	ConflictSet* cs = newConflictSet();

	Arena testDataArena;
	VectorRef<VectorRef<KeyRangeRef>> testData;
	testData.resize(testDataArena, 500);
	std::vector<std::vector<uint8_t>> success(testData.size());
	std::vector<std::vector<uint8_t>> success2(testData.size());
	for (int i = 0; i < testData.size(); i++) {
		testData[i].resize(testDataArena, 5000);
		success[i].assign(testData[i].size(), false);
		success2[i].assign(testData[i].size(), false);
		for (int j = 0; j < testData[i].size(); j++) {
			int key = deterministicRandom()->randomInt(0, 20000000);
			int key2 = key + 1 + deterministicRandom()->randomInt(0, 10);
			testData[i][j] = KeyRangeRef(setK(testDataArena, key), setK(testDataArena, key2));
		}
	}
	printf("Test data generated (%d)\n", deterministicRandom()->randomInt(0, 100000));
	printf("  %d threads, %d batches, %d/batch\n", PARALLEL_THREAD_COUNT, testData.size(), testData[0].size());

	printf("Running\n");

	int readCount = 1, writeCount = 1;
	int cranges = 0, tcount = 0;

	start = timer();
	std::vector<std::vector<int>> nonConflict(testData.size());
	for (int i = 0; i < testData.size(); i++) {
		Arena buf;
		std::vector<CommitTransactionRef> trs;
		double t = timer();
		for (int j = 0; j + readCount + writeCount <= testData[i].size(); j += readCount + writeCount) {
			CommitTransactionRef tr;
			for (int k = 0; k < readCount; k++) {
				KeyRangeRef r(buf, testData[i][j + k]);
				tr.read_conflict_ranges.push_back(buf, r);
			}
			for (int k = 0; k < writeCount; k++) {
				KeyRangeRef r(buf, testData[i][j + readCount + k]);
				tr.write_conflict_ranges.push_back(buf, r);
			}
			cranges += tr.read_conflict_ranges.size() + tr.write_conflict_ranges.size();
			tr.read_snapshot = i;
			trs.push_back(tr);
		}
		tcount += trs.size();
		g_buildTest += timer() - t;

		t = timer();
		ConflictBatch batch(cs);
		for (int j = 0; j < trs.size(); j++) batch.addTransaction(trs[j]);
		g_add += timer() - t;

		t = timer();
		batch.detectConflicts(i + 50, i, nonConflict[i]);
		g_detectConflicts += timer() - t;
	}
	double elapsed = timer() - start;
	printf("New conflict set: %0.3f sec\n", elapsed);
	printf("                  %0.3f Mtransactions/sec\n", tcount / elapsed / 1e6);
	printf("                  %0.3f Mkeys/sec\n", cranges * 2 / elapsed / 1e6);

	elapsed = g_detectConflicts.getValue();
	printf("Detect only:      %0.3f sec\n", elapsed);
	printf("                  %0.3f Mtransactions/sec\n", tcount / elapsed / 1e6);
	printf("                  %0.3f Mkeys/sec\n", cranges * 2 / elapsed / 1e6);

	elapsed = g_checkRead.getValue() + g_merge.getValue();
	printf("Skiplist only:    %0.3f sec\n", elapsed);
	printf("                  %0.3f Mtransactions/sec\n", tcount / elapsed / 1e6);
	printf("                  %0.3f Mkeys/sec\n", cranges * 2 / elapsed / 1e6);

	printf("Performance counters:\n");
	for (int c = 0; c < skc.size(); c++) {
		printf("%20s: %s\n", skc[c]->getMetric().name().c_str(), skc[c]->getMetric().formatted().c_str());
	}

	// showNumaStatus();

	printf("%d entries in version history\n", cs->versionHistory.count());

	/*start = timer();
	vector<vector<int>> nonConflict2( testData.size() );
	SlowConflictSet scs;
	Standalone<VectorRef<KeyRangeRef>> ranges;
	ranges.resize( ranges.arena(), 1 );

	for(int i=0; i<testData.size(); i++) {
	    for(int j=0; j<testData[i].size(); j++) {
	        ranges[0] = testData[i][j];
	        if (!scs.is_conflict( ranges, i )) {
	            nonConflict2[i].push_back( j );
	            scs.add( ranges, VectorRef<KeyValueRef>(), i + 50 );
	        }
	    }
	}
	printf("Old conflict set: %0.3f sec\n", timer()-start);

	int aminusb=0, bminusa=0, atotal=0;
	for(int i=0; i<testData.size(); i++) {
	    vector<bool> a( testData[i].size() ), b( testData[i].size() );
	    for(int j=0; j<nonConflict[i].size(); j++)
	        a[ nonConflict[i][j] ] = true;
	    for(int j=0; j<nonConflict2[i].size(); j++)
	        b[ nonConflict2[i][j] ] = true;
	    for(int j=0; j<a.size(); j++) {
	        if (a[j]) atotal++;
	        if (a[j] && !b[j]) aminusb++;
	        else if (b[j] && !a[j]) bminusa++;
	    }
	}
	printf("%d transactions accepted\n", atotal);
	if (bminusa)
	    printf("ERROR: %d transactions unnecessarily rejected!\n", bminusa);
	if (aminusb)
	    printf("ERROR: %d transactions incorrectly accepted!\n", aminusb);
	    */
	// for(int i=0; i<testData.size(); i++)
	//	printf("%d %d %d %d\n", i, nonConflict[i].size(), nonConflict2[i].size()-nonConflict[i].size(), nonConflict[i]
	//!= nonConflict2[i]);
}