Commit 942204a4 authored by Philip Pronin's avatar Philip Pronin Committed by Sara Golemon

streaming support for EF compression

Test Plan: fbconfig -r folly/experimental/test:eliasfano_test && fbmake opt -j32

Reviewed By: lucian@fb.com

Subscribers: chaoyc, search-fbcode-diffs@, unicorn-diffs@

FB internal diff: D1474625

Tasks: 4828866
parent af59f4c1
......@@ -32,7 +32,6 @@
#error EliasFanoCoding.h requires x86_64
#endif
#include <algorithm>
#include <cstdlib>
#include <limits>
#include <type_traits>
......@@ -51,8 +50,7 @@
namespace folly { namespace compression {
struct EliasFanoCompressedList {
EliasFanoCompressedList()
: size(0), numLowerBits(0) { }
EliasFanoCompressedList() { }
void free() {
::free(const_cast<unsigned char*>(lower.data()));
......@@ -61,8 +59,8 @@ struct EliasFanoCompressedList {
::free(const_cast<unsigned char*>(forwardPointers.data()));
}
size_t size;
uint8_t numLowerBits;
size_t size = 0;
uint8_t numLowerBits = 0;
// WARNING: EliasFanoCompressedList has no ownership of
// lower, upper, skipPointers and forwardPointers.
......@@ -106,30 +104,29 @@ struct EliasFanoEncoder {
return folly::findLastSet(upperBound / size) - 1;
}
// Requires: input range (begin, end) is sorted (encoding
// crashes if it's not).
// WARNING: encode() mallocates lower, upper, skipPointers
// and forwardPointers. As EliasFanoCompressedList has
// no ownership of them, you need to call free() explicitly.
static void encode(const ValueType* list, size_t size,
EliasFanoCompressedList& result) {
encode(list, list + size, result);
}
// Range (begin, end) should be sorted.
template <class RandomAccessIterator>
static void encode(RandomAccessIterator begin,
RandomAccessIterator end,
EliasFanoCompressedList& result) {
CHECK(std::is_sorted(begin, end));
auto list = begin;
const size_t size = end - begin;
static EliasFanoCompressedList encode(RandomAccessIterator begin,
RandomAccessIterator end) {
if (begin == end) {
return EliasFanoCompressedList();
}
EliasFanoEncoder encoder(end - begin, *(end - 1));
for (; begin != end; ++begin) {
encoder.add(*begin);
}
return encoder.finish();
}
EliasFanoEncoder(size_t size, ValueType upperBound) {
if (size == 0) {
result = EliasFanoCompressedList();
return;
}
const ValueType upperBound = list[size - 1];
uint8_t numLowerBits = defaultNumLowerBits(upperBound, size);
// This is detail::writeBits56 limitation.
......@@ -144,14 +141,8 @@ struct EliasFanoEncoder {
// *** Lower bits.
const size_t lowerSize = (numLowerBits * size + 7) / 8;
unsigned char* lower = nullptr;
if (lowerSize > 0) { // numLowerBits != 0
lower = static_cast<unsigned char*>(calloc(lowerSize + 7, 1));
const ValueType lowerMask = (ValueType(1) << numLowerBits) - 1;
for (size_t i = 0; i < size; ++i) {
const ValueType lowerBits = list[i] & lowerMask;
writeBits56(lower, i * numLowerBits, numLowerBits, lowerBits);
}
lower_ = static_cast<unsigned char*>(calloc(lowerSize + 7, 1));
}
// *** Upper bits.
......@@ -161,22 +152,13 @@ struct EliasFanoEncoder {
(upperBound >> numLowerBits) + // Number of 0-bits to be stored.
size; // 1-bits.
const size_t upperSize = (upperSizeBits + 7) / 8;
unsigned char* const upper =
static_cast<unsigned char*>(calloc(upperSize + 7, 1));
for (size_t i = 0; i < size; ++i) {
const ValueType upperBits = list[i] >> numLowerBits;
const size_t pos = upperBits + i; // upperBits 0-bits and (i + 1) 1-bits.
upper[pos / 8] |= 1U << (pos % 8);
}
upper_ = static_cast<unsigned char*>(calloc(upperSize + 7, 1));
// *** Skip pointers.
// Store (1-indexed) position of every skipQuantum-th
// 0-bit in upper bits sequence.
SkipValueType* skipPointers = nullptr;
size_t numSkipPointers = 0;
/* static */ if (skipQuantum != 0) {
// Workaround to avoid 'division by zero' compile-time error.
constexpr size_t q = skipQuantum ?: 1;
/* static */ if (kVersion > 0) {
CHECK_LT(size, std::numeric_limits<SkipValueType>::max());
} else {
......@@ -186,33 +168,18 @@ struct EliasFanoEncoder {
// more serialization-friendly way (upperSizeBits isn't known outside of
// this function, unlike upperSize; thus numSkipPointers could easily be
// deduced from upperSize).
numSkipPointers = (8 * upperSize - size) / q;
skipPointers = static_cast<SkipValueType*>(
numSkipPointers = (8 * upperSize - size) / (skipQuantum ?: 1);
skipPointers_ = static_cast<SkipValueType*>(
numSkipPointers == 0
? nullptr
: calloc(numSkipPointers, sizeof(SkipValueType)));
for (size_t i = 0, pos = 0; i < size; ++i) {
const ValueType upperBits = list[i] >> numLowerBits;
for (; (pos + 1) * q <= upperBits; ++pos) {
/* static */ if (kVersion > 0) {
// Since version 1, just the number of preceding 1-bits is stored.
skipPointers[pos] = i;
} else {
skipPointers[pos] = i + (pos + 1) * q;
}
}
}
}
// *** Forward pointers.
// Store (1-indexed) position of every forwardQuantum-th
// 1-bit in upper bits sequence.
SkipValueType* forwardPointers = nullptr;
size_t numForwardPointers = 0;
/* static */ if (forwardQuantum != 0) {
// Workaround to avoid 'division by zero' compile-time error.
constexpr size_t q = forwardQuantum ?: 1;
/* static */ if (kVersion > 0) {
CHECK_LT(upperBound >> numLowerBits,
std::numeric_limits<SkipValueType>::max());
......@@ -220,34 +187,74 @@ struct EliasFanoEncoder {
CHECK_LT(upperSizeBits, std::numeric_limits<SkipValueType>::max());
}
numForwardPointers = size / q;
forwardPointers = static_cast<SkipValueType*>(
// '?: 1' is a workaround for false 'division by zero' compile-time error.
numForwardPointers = size / (forwardQuantum ?: 1);
forwardPointers_ = static_cast<SkipValueType*>(
numForwardPointers == 0
? nullptr
: malloc(numForwardPointers * sizeof(SkipValueType)));
}
// *** Result.
result_.size = size;
result_.numLowerBits = numLowerBits;
result_.lower.reset(lower_, lowerSize);
result_.upper.reset(upper_, upperSize);
result_.skipPointers.reset(
reinterpret_cast<unsigned char*>(skipPointers_),
numSkipPointers * sizeof(SkipValueType));
result_.forwardPointers.reset(
reinterpret_cast<unsigned char*>(forwardPointers_),
numForwardPointers * sizeof(SkipValueType));
}
void add(ValueType value) {
CHECK_GE(value, lastValue_);
for (size_t i = q - 1, pos = 0; i < size; i += q, ++pos) {
const ValueType upperBits = list[i] >> numLowerBits;
const auto numLowerBits = result_.numLowerBits;
const ValueType upperBits = value >> numLowerBits;
// Upper sequence consists of upperBits 0-bits and (size_ + 1) 1-bits.
const size_t pos = upperBits + size_;
upper_[pos / 8] |= 1U << (pos % 8);
// Append numLowerBits bits to lower sequence.
if (numLowerBits != 0) {
const ValueType lowerBits = value & ((ValueType(1) << numLowerBits) - 1);
writeBits56(lower_, size_ * numLowerBits, numLowerBits, lowerBits);
}
/* static */ if (skipQuantum != 0) {
while ((skipPointersSize_ + 1) * skipQuantum <= upperBits) {
/* static */ if (kVersion > 0) {
// Since version 1, just the number of preceding 1-bits is stored.
skipPointers_[skipPointersSize_] = size_;
} else {
skipPointers_[skipPointersSize_] =
size_ + (skipPointersSize_ + 1) * skipQuantum;
}
++skipPointersSize_;
}
}
/* static */ if (forwardQuantum != 0) {
if ((size_ + 1) % forwardQuantum == 0) {
const auto pos = size_ / forwardQuantum;
/* static */ if (kVersion > 0) {
// Since version 1, just the number of preceding 0-bits is stored.
forwardPointers[pos] = upperBits;
forwardPointers_[pos] = upperBits;
} else {
forwardPointers[pos] = upperBits + i + 1;
forwardPointers_[pos] = upperBits + size_ + 1;
}
}
}
// *** Result.
result.size = size;
result.numLowerBits = numLowerBits;
result.lower.reset(lower, lowerSize);
result.upper.reset(upper, upperSize);
result.skipPointers.reset(
reinterpret_cast<unsigned char*>(skipPointers),
numSkipPointers * sizeof(SkipValueType));
result.forwardPointers.reset(
reinterpret_cast<unsigned char*>(forwardPointers),
numForwardPointers * sizeof(SkipValueType));
lastValue_ = value;
++size_;
}
const EliasFanoCompressedList& finish() const {
CHECK_EQ(size_, result_.size);
return result_;
}
private:
......@@ -261,6 +268,17 @@ struct EliasFanoEncoder {
ptrv |= value << (pos % 8);
folly::storeUnaligned<uint64_t>(ptr, ptrv);
}
unsigned char* lower_ = nullptr;
unsigned char* upper_ = nullptr;
SkipValueType* skipPointers_ = nullptr;
SkipValueType* forwardPointers_ = nullptr;
ValueType lastValue_ = 0;
size_t size_ = 0;
size_t skipPointersSize_ = 0;
EliasFanoCompressedList result_;
};
// NOTE: It's recommended to compile EF coding with -msse4.2, starting
......
......@@ -177,9 +177,8 @@ void testGoTo(const std::vector<uint32_t>& data, const List& list) {
template <class Reader, class Encoder>
void testEmpty() {
typename Encoder::CompressedList list;
const typename Encoder::ValueType* const data = nullptr;
Encoder::encode(data, 0, list);
auto list = Encoder::encode(data, data);
{
Reader reader(list);
EXPECT_FALSE(reader.next());
......@@ -198,8 +197,7 @@ void testEmpty() {
template <class Reader, class Encoder>
void testAll(const std::vector<uint32_t>& data) {
typename Encoder::CompressedList list;
Encoder::encode(data.begin(), data.end(), list);
auto list = Encoder::encode(data.begin(), data.end());
testNext<Reader>(data, list);
testSkip<Reader>(data, list);
testSkipTo<Reader>(data, list);
......
......@@ -82,6 +82,9 @@ typedef EliasFanoReader<Encoder> Reader;
std::vector<uint32_t> data;
std::vector<size_t> order;
std::vector<uint32_t> encodeSmallData;
std::vector<uint32_t> encodeLargeData;
typename Encoder::CompressedList list;
void init() {
......@@ -89,7 +92,7 @@ void init() {
data = generateRandomList(100 * 1000, 10 * 1000 * 1000, gen);
//data = loadList("/home/philipp/pl_test_dump.txt");
Encoder::encode(data.data(), data.size(), bm::list);
list = Encoder::encode(data.begin(), data.end());
order.clear();
order.reserve(data.size());
......@@ -97,6 +100,9 @@ void init() {
order.push_back(i);
}
std::shuffle(order.begin(), order.end(), gen);
encodeSmallData = generateRandomList(10, 100 * 1000, gen);
encodeLargeData = generateRandomList(1000 * 1000, 100 * 1000 * 1000, gen);
}
void free() {
......@@ -133,6 +139,8 @@ BENCHMARK(SkipTo1_SkipQ128_1M) {
bmSkipTo<bm::Reader>(bm::list, bm::data, 1, bm::k1M);
}
BENCHMARK_DRAW_LINE();
BENCHMARK(SkipTo10_SkipQ128_1M) {
bmSkipTo<bm::Reader>(bm::list, bm::data, 10, bm::k1M);
}
......@@ -145,8 +153,22 @@ BENCHMARK(SkipTo1000_SkipQ128_1M) {
bmSkipTo<bm::Reader>(bm::list, bm::data, 1000, bm::k1M);
}
BENCHMARK_DRAW_LINE();
BENCHMARK(Encode_10) {
auto list = bm::Encoder::encode(bm::encodeSmallData.begin(),
bm::encodeSmallData.end());
list.free();
}
BENCHMARK(Encode_1M) {
auto list = bm::Encoder::encode(bm::encodeLargeData.begin(),
bm::encodeLargeData.end());
list.free();
}
#if 0
Intel Xeon CPU E5-2660 @ 2.7GHz (turbo on), using instructions::Fast.
Intel(R) Xeon(R) CPU E5-2660 @ 2.7GHz (turbo on), using instructions::Fast.
============================================================================
folly/experimental/test/EliasFanoCodingTest.cpp relative time/iter iters/s
......@@ -157,10 +179,14 @@ Skip10_ForwarQ128_1M 13.69ms 73.03
Skip100_ForwardQ128_1M 26.76ms 37.37
Skip1000_ForwardQ128_1M 20.66ms 48.40
GoTo_ForwardQ128_1M 43.75ms 22.86
----------------------------------------------------------------------------
SkipTo1_SkipQ128_1M 9.74ms 102.70
SkipTo10_SkipQ128_1M 30.62ms 32.66
SkipTo100_SkipQ128_1M 37.70ms 26.53
SkipTo1000_SkipQ128_1M 31.14ms 32.11
----------------------------------------------------------------------------
Encode_10 208.16ns 4.80M
Encode_1M 8.90ms 112.37
============================================================================
#endif
......
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