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-rw-r--r--db/memtable.cu246
-rw-r--r--db/memtable.cuh325
2 files changed, 533 insertions, 38 deletions
diff --git a/db/memtable.cu b/db/memtable.cu
index 241a35b..51ca578 100644
--- a/db/memtable.cu
+++ b/db/memtable.cu
@@ -20,7 +20,6 @@ static Slice GetLengthPrefixedSlice(const char* data) {
MemTable::MemTable(const InternalKeyComparator& comparator)
: comparator_(comparator), refs_(0) {
-
}
MemTable::~MemTable() { assert(refs_ == 0); }
@@ -266,4 +265,249 @@ bool MemTable::Get(const LookupKey& key, std::string* value, Status* s) {
return false;
}
+__device__ const char* GetVarint32PtrFallbackCuda(const char* p, const char* limit,
+ uint32_t* value) {
+ uint32_t result = 0;
+ for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
+ uint32_t byte = *(reinterpret_cast<const uint8_t*>(p));
+ p++;
+ if (byte & 128) {
+ // More bytes are present
+ result |= ((byte & 127) << shift);
+ } else {
+ result |= (byte << shift);
+ *value = result;
+ return reinterpret_cast<const char*>(p);
+ }
+ }
+ return nullptr;
+}
+
+__device__ inline const char* GetVarint32PtrCuda(const char* p, const char* limit,
+ uint32_t* value) {
+ if (p < limit) {
+ uint32_t result = *(reinterpret_cast<const uint8_t*>(p));
+ if ((result & 128) == 0) {
+ *value = result;
+ return p + 1;
+ }
+ }
+ return GetVarint32PtrFallbackCuda(p, limit, value);
+}
+
+struct SizedSlice {
+ const char * ptr;
+ size_t len;
+
+ __device__ __host__ explicit SizedSlice(const char * ptr, size_t len) {
+ this->ptr = ptr;
+ this->len = len;
+ }
+};
+
+__device__ static SizedSlice GetLengthPrefixedSliceCuda(const char* data) {
+ uint32_t len;
+ const char* p = data;
+ p = GetVarint32PtrCuda(p, p + 5, &len); // +5: we assume "p" is not corrupted
+ return SizedSlice(p, len);
+}
+
+
+__device__ MemTableCuda::MemTableCuda(const InternalKeyComparator& comparator)
+ : comparator_(comparator), refs_(0), table_(comparator_, &arena_) {
+}
+
+MemTableCuda::~MemTableCuda() { assert(refs_ == 0); }
+
+size_t MemTableCuda::ApproximateMemoryUsage() { return arena_.MemoryUsage(); }
+
+__device__ int MemTableCuda::KeyComparator::operator()(const char* aptr,
+ const char* bptr) const {
+ // Internal keys are encoded as length-prefixed strings.
+ Slice a = GetLengthPrefixedSliceCuda(aptr);
+ Slice b = GetLengthPrefixedSliceCuda(bptr);
+ return comparator.Compare(a, b);
+}
+
+class MemTableCudaIterator : public Iterator {
+ public:
+ explicit MemTableCudaIterator(MemTableCuda::Table* table) : iter_(table) {}
+
+ MemTableCudaIterator(const MemTableCudaIterator&) = delete;
+ MemTableCudaIterator& operator=(const MemTableCudaIterator&) = delete;
+
+ ~MemTableCudaIterator() override = default;
+
+ bool Valid() const override { return iter_.Valid(); }
+ void Seek(const Slice& k) override {
+ char * key = nullptr;
+ EncodeKey(&tmp_, k);
+ Seek_<<<1, 1>>>(this, key);
+ }
+ void SeekToFirst() override { iter_.SeekToFirst(); }
+ void SeekToLast() override { iter_.SeekToLast(); }
+ void Next() override { iter_.Next(); }
+ void Prev() override { Prev_<<<1, 1>>>(this); }
+ Slice key() const override { return GetLengthPrefixedSlice(iter_.key()); }
+ Slice value() const override {
+ Slice key_slice = GetLengthPrefixedSlice(iter_.key());
+ return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
+ }
+
+ Status status() const override { return Status::OK(); }
+
+ static __global__ void Prev_(MemTableCudaIterator* this_) {
+ this_->iter_.Prev();
+ }
+
+ static __global__ void Seek_(MemTableCudaIterator* this_, const char * key) {
+ this_->iter_.Seek(key);
+ }
+
+ private:
+ MemTableCuda::Table::Iterator iter_;
+ std::string tmp_; // For passing to EncodeKey
+};
+
+Iterator* MemTableCuda::NewIterator() { return new MemTableCudaIterator(&table_); }
+
+
+__global__ void MemTableCudaAdd_(MemTableCuda * mtb, size_t encoded_len, char * encode_data) {
+ char* buf = mtb->arena_.Allocate(encoded_len);
+ memcpy(buf, encode_data, encoded_len);
+ mtb->table_.Insert(buf);
+}
+
+
+void MemTableCuda::Add(SequenceNumber s, ValueType type, const Slice& key,
+ const Slice& value) {
+ // Format of an entry is concatenation of:
+ // key_size : varint32 of internal_key.size()
+ // key bytes : char[internal_key.size()]
+ // tag : uint64((sequence << 8) | type)
+ // value_size : varint32 of value.size()
+ // value point : point to host memory
+ size_t key_size = key.size();
+ size_t val_size = value.size();
+ size_t internal_key_size = key_size + 8;
+ //const size_t encoded_len = VarintLength(internal_key_size) +
+ // internal_key_size + VarintLength(val_size) +
+ // val_size;
+ const size_t encoded_len = VarintLength(internal_key_size) + internal_key_size +
+ VarintLength(val_size) + 8;
+
+
+ char * key_mem = this->arena_.Allocate( key_size);
+ std::memcpy(key_mem, key.data(), key_size);
+
+ //char * tag_mem = key_mem + key_size;
+ //EncodeFixed64(tag_mem, (s << 8) | type);
+
+ char * val_mem = this->arena_.Allocate(val_size);
+ std::memcpy(val_mem, value.data(), val_size);
+
+ char * insert_val = new char[encoded_len], *cuda_insert = nullptr;
+ // EncodeVarint32(insert_val, encoded_len);
+ char * p = EncodeVarint32(insert_val + 8, internal_key_size);
+ //EncodeFixed64(p, reinterpret_cast<uint64_t>(key_mem));
+ memcpy(p, key_mem, key_size);
+ p += key_size;
+ EncodeFixed64(p, (s << 8) | type );
+ p += 8;
+ //EncodeFixed64(p, reinterpret_cast<uint64_t>(val_size));
+ p = EncodeVarint32(p, val_size);
+ EncodeFixed64(p, reinterpret_cast<uint64_t>(val_mem));
+
+ assert(p + 8 == insert_val + encoded_len);
+
+ cudaMalloc((void**)&cuda_insert, encoded_len);
+ cudaMemcpy(cuda_insert, insert_val, encoded_len, cudaMemcpyHostToDevice);
+
+ MemTableCudaAdd_<<<1, 1>>>(this, encoded_len, cuda_insert);
+ cudaDeviceSynchronize();
+
+ cudaFree(cuda_insert);
+ delete[] insert_val;
+}
+
+__global__ void MemTableCudaGet_(MemTableCuda * met, char * memkey, char ** data, size_t* malloc_size) {
+ *data = nullptr;
+ auto iter = met->getIter();
+ iter.Seek(memkey);
+ if (iter.Valid()) {
+ // entry format is:
+ // klength varint32
+ // userkey char[klength]
+ // tag uint64
+ // vlength varint32
+ // value char[vlength]
+ // Check that it belongs to same user key. We do not check the
+ // sequence number since the Seek() call above should have skipped
+ // all entries with overly large sequence numbers.
+ size_t key_size;
+ const char *entry = iter.key();
+ const char * p = GetVarint32PtrCuda(entry, entry + 5,
+ reinterpret_cast<uint32_t*>(&key_size));
+ p = GetVarint32PtrCuda(p + key_size, p + key_size + 5, nullptr);
+ *malloc_size = (p - entry + 8);
+ cudaMalloc((void**)*data, *malloc_size);
+ memcpy(*data, entry, *malloc_size);
+ }
+}
+
+bool MemTableCuda::Get(const LookupKey& key, std::string* value, Status* s) {
+
+ Slice memkey = key.memtable_key();
+ char * cuda_mem_key = nullptr;
+ cudaMalloc((void**)&cuda_mem_key, memkey.size());
+ cudaMemcpy(cuda_mem_key, memkey.data(), memkey.size(), cudaMemcpyHostToDevice);
+
+ char ** cuda_skiplist_key = nullptr;
+ cudaMalloc((void**)&cuda_skiplist_hkey, sizeof(char *));
+
+ size_t * cuda_malloc_size = nullptr;
+ cudaMalloc((void**)&cuda_malloc_size, sizeof(cuda_malloc_size));
+
+ MemTableCudaGet_<<<1,1>>>(this, cuda_mem_key, cuda_skiplist_key, cuda_malloc_size);
+ cudaDeviceSynchronize();
+ cudaFree(cuda_mem_key);
+
+ if (*cuda_skiplist_key == nullptr) {
+ cudaFree(cuda_skiplist_key);
+ cudaFree(cuda_malloc_size);
+ return false;
+ }
+ auto * malloc_size = new size_t;
+ cudaMemcpy(malloc_size, cuda_malloc_size, sizeof(size_t), cudaMemcpyDeviceToHost);
+
+ char * entry = this->host_arena_.Allocate(*malloc_size);
+ cudaMemcpy(entry, cuda_skiplist_key, *malloc_size, cudaMemcpyDeviceToHost);
+
+ cudaFree(cuda_skiplist_key);
+ cudaFree(cuda_malloc_size);
+ delete malloc_size;
+
+ uint32_t key_length;
+ const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
+ if (comparator_.comparator.user_comparator()->Compare(
+ Slice(key_ptr, key_length - 8), key.user_key()) == 0) {
+ // Correct user key
+ const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
+ switch (static_cast<ValueType>(tag & 0xff)) {
+ case kTypeValue: {
+ // HOW CAN WE GET IT?
+ Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
+ value->assign(v.data(), v.size());
+ return true;
+ }
+ case kTypeDeletion:
+ *s = Status::NotFound(Slice());
+ return true;
+ }
+ }
+
+
+ return false;
+}
+
} // namespace leveldb
diff --git a/db/memtable.cuh b/db/memtable.cuh
index 766eb03..6f0b2cd 100644
--- a/db/memtable.cuh
+++ b/db/memtable.cuh
@@ -18,36 +18,6 @@ namespace leveldb {
class InternalKeyComparator;
class MemTableIterator;
-__device__ const char* GetVarint32PtrFallbackCuda(const char* p, const char* limit,
- uint32_t* value) {
- uint32_t result = 0;
- for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
- uint32_t byte = *(reinterpret_cast<const uint8_t*>(p));
- p++;
- if (byte & 128) {
- // More bytes are present
- result |= ((byte & 127) << shift);
- } else {
- result |= (byte << shift);
- *value = result;
- return reinterpret_cast<const char*>(p);
- }
- }
- return nullptr;
-}
-
-__device__ inline const char* GetVarint32PtrCuda(const char* p, const char* limit,
- uint32_t* value) {
- if (p < limit) {
- uint32_t result = *(reinterpret_cast<const uint8_t*>(p));
- if ((result & 128) == 0) {
- *value = result;
- return p + 1;
- }
- }
- return GetVarint32PtrFallbackCuda(p, limit, value);
-}
-
struct SizedString {
char * data;
size_t length;
@@ -73,13 +43,6 @@ struct SizedString {
};
-__device__ static SizedString GetLengthPrefixedSliceCuda(const char* data) {
- uint32_t len;
- const char* p = data;
- p = GetVarint32PtrCuda(p, p + 5, &len); // +5: we assume "p" is not corrupted
- return SizedString(p, len);
-}
-
class MemTable {
public:
// MemTables are reference counted. The initial reference count
@@ -154,6 +117,294 @@ class MemTable {
Table table_;
};
+
+class CudaSlice;
+
+// A Comparator object provides a total order across slices that are
+// used as keys in an sstable or a database. A Comparator implementation
+// must be thread-safe since leveldb may invoke its methods concurrently
+// from multiple threads.
+class LEVELDB_EXPORT CudaComparator {
+ public:
+ virtual ~CudaComparator();
+
+ virtual __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const = 0;
+
+ virtual __device__ __host__ const char* Name() const = 0;
+
+ virtual __device__ void FindShortestSeparator(const CudaSlice* start,
+ const CudaSlice& limit) const = 0;
+
+ virtual __device__ void FindShortSuccessor(CudaSlice* key) const = 0;
+};
+
+// Return a builtin comparator that uses lexicographic byte-wise
+// ordering. The result remains the property of this module and
+// must not be deleted.
+LEVELDB_EXPORT const Comparator* BytewiseComparator();
+
+
+// A comparator for internal keys that uses a specified comparator for
+// the user key portion and breaks ties by decreasing sequence number.
+class CudaInternalKeyComparator : public CudaComparator {
+ private:
+ const CudaComparator* user_comparator_;
+
+ public:
+ explicit CudaInternalKeyComparator(const CudaComparator* c) : user_comparator_(c) {}
+ __device__ __host__ const char* Name() const override;
+ __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const override;
+ __device__ void FindShortestSeparator(const CudaSlice* start,
+ const CudaSlice& limit) const override;
+ __device__ void FindShortSuccessor(CudaSlice* key) const override;
+
+ __device__ __host__ const CudaComparator* user_comparator() const { return user_comparator_; }
+
+ __device__ int Compare(const InternalKey& a, const InternalKey& b) const;
+};
+
+
+class LEVELDB_EXPORT CudaSlice {
+ public:
+ // Create an empty slice.
+ CudaSlice() : data_(""), size_(0) {}
+
+ // Create a slice that refers to d[0,n-1].
+ CudaSlice(const char* d, size_t n) : data_(d), size_(n) {}
+
+ // Create a slice that refers to the contents of "s"
+ //CudaSlice(const std::string& s) : data_(s.data()), size_(s.size()) {}
+
+ // Create a slice that refers to s[0,strlen(s)-1]
+ CudaSlice(const char* s) : data_(s), size_(strlen(s)) {}
+
+ // Intentionally copyable.
+ CudaSlice(const CudaSlice&) = default;
+ CudaSlice& operator=(const CudaSlice&) = default;
+
+ // Return a pointer to the beginning of the referenced data
+ __device__ const char* data() const { return data_; }
+
+ // Return the length (in bytes) of the referenced data
+ __device__ __host__ size_t size() const { return size_; }
+
+ // Return true iff the length of the referenced data is zero
+ __device__ __host__ bool empty() const { return size_ == 0; }
+
+ // Return the ith byte in the referenced data.
+ // REQUIRES: n < size()
+ /*__device__ char operator[](size_t n) const {
+ assert(n < size());
+ return data_[n];
+ }*/
+ __device__ char get_index(size_t n) const {
+ assert(n < size());
+ return data_[n];
+ }
+
+ // Change this slice to refer to an empty array
+ __device__ __host__ void clear() {
+ data_ = nullptr;
+ size_ = 0;
+ }
+
+ // Drop the first "n" bytes from this slice.
+ void remove_prefix(size_t n) {
+ assert(n <= size());
+ data_ += n;
+ size_ -= n;
+ }
+
+ // Return a string that contains the copy of the referenced data.
+ //std::string ToString() const { return std::string(data_, size_); }
+
+ // Three-way comparison. Returns value:
+ // < 0 iff "*this" < "b",
+ // == 0 iff "*this" == "b",
+ // > 0 iff "*this" > "b"
+ __device__ int compare(const CudaSlice& b) const;
+
+ // Return true iff "x" is a prefix of "*this"
+ bool starts_with(const CudaSlice& x) const {
+ return ((size_ >= x.size_) && (memcmp(data_, x.data_, x.size_) == 0));
+ }
+
+ private:
+ const char* data_;
+ size_t size_;
+};
+
+
+template<typename T>
+__device__ T cudaMin(const T & a, const T &b) {
+ return a>b?a:b;
+}
+
+CudaComparator::~CudaComparator() = default;
+
+namespace {
+class BytewiseComparatorImpl : public CudaComparator {
+ public:
+ BytewiseComparatorImpl() = default;
+
+
+
+ __device__ __host__ const char* Name() const override { return "leveldb.BytewiseComparator"; }
+
+ __device__ int Compare(const CudaSlice& a, const CudaSlice& b) const override {
+ return a.compare(b);
+ }
+
+ __device__ void FindShortestSeparator(const CudaSlice * start,
+ const CudaSlice& limit) const override {
+ // Find length of common prefix
+ size_t min_length = std::min(start->size(), limit.size());
+ size_t diff_index = 0;
+ while ((diff_index < min_length) &&
+ ((*start)[diff_index] == limit[diff_index])) {
+ diff_index++;
+ }
+
+ if (diff_index >= min_length) {
+ // Do not shorten if one string is a prefix of the other
+ } else {
+ uint8_t diff_byte = static_cast<uint8_t>((*start)[diff_index]);
+ if (diff_byte < static_cast<uint8_t>(0xff) &&
+ diff_byte + 1 < static_cast<uint8_t>(limit[diff_index])) {
+ (*start)[diff_index]++;
+ start->resize(diff_index + 1);
+ assert(Compare(*start, limit) < 0);
+ }
+ }
+ }
+
+ void FindShortSuccessor(CudaSlice* key) const override {
+ // Find first character that can be incremented
+ size_t n = key->size();
+ for (size_t i = 0; i < n; i++) {
+ const uint8_t byte = (*key)[i];
+ if (byte != static_cast<uint8_t>(0xff)) {
+ (*key)[i] = byte + 1;
+ key->resize(i + 1);
+ return;
+ }
+ }
+ // *key is a run of 0xffs. Leave it alone.
+ }
+};
+} // namespace
+
+const Comparator* BytewiseComparator() {
+ static NoDestructor<BytewiseComparatorImpl> singleton;
+ return singleton.get();
+}
+
+template<typename T>
+__device__ int cudaMemcmp(const T * a, const T * b, size_t min_length) {
+ for (size_t i = 0; i < min_length ; i++) {
+ if (a[i] == b[i])
+ continue;
+ return a[i] < b[i] ? -1 : 1;
+ }
+ return 0;
+}
+
+/*__device__ inline bool operator==(const CudaSlice& x, const CudaSlice& y) {
+ return ((x.size() == y.size()) &&
+ (cudaMemcmp(x.data(), y.data(), x.size()) == 0));
+}*/
+
+/*inline bool operator!=(const CudaSlice& x, const CudaSlice& y) { return !(x == y); }*/
+
+
+
+__device__ inline int CudaSlice::compare(const CudaSlice& b) const {
+ const size_t min_len = (size_ < b.size_) ? size_ : b.size_;
+ int r = cudaMemcmp(data_, b.data_, min_len);
+ if (r == 0) {
+ if (size_ < b.size_)
+ r = -1;
+ else if (size_ > b.size_)
+ r = +1;
+ }
+ return r;
+}
+
+
+
+class MemTableCuda {
+ public:
+ // MemTables are reference counted. The initial reference count
+ // is zero and the caller must call Ref() at least once.
+ __device__ explicit MemTableCuda(const InternalKeyComparator& comparator);
+
+ MemTableCuda(const MemTableCuda&) = delete;
+ MemTableCuda& operator=(const MemTableCuda&) = delete;
+
+ // Increase reference count.
+ void Ref() { ++refs_; }
+
+ // Drop reference count. Delete if no more references exist.
+ void Unref() {
+ --refs_;
+ assert(refs_ >= 0);
+ if (refs_ <= 0) {
+ delete this;
+ }
+ }
+
+ // Returns an estimate of the number of bytes of data in use by this
+ // data structure. It is safe to call when MemTable is being modified.
+ size_t ApproximateMemoryUsage();
+
+ // Return an iterator that yields the contents of the memtable.
+ //
+ // The caller must ensure that the underlying MemTable remains live
+ // while the returned iterator is live. The keys returned by this
+ // iterator are internal keys encoded by AppendInternalKey in the
+ // db/format.{h,cc} module.
+ Iterator* NewIterator();
+
+ // Add an entry into memtable that maps key to value at the
+ // specified sequence number and with the specified type.
+ // Typically value will be empty if type==kTypeDeletion.
+ __device__ void Add(SequenceNumber seq, ValueType type, const CudaSlice& key,
+ const Slice& value);
+
+ // If memtable contains a value for key, store it in *value and return true.
+ // If memtable contains a deletion for key, store a NotFound() error
+ // in *status and return true.
+ // Else, return false.
+ __device__ bool Get(const LookupKey& key, std::string* value, Status* s);
+
+ private:
+ friend class MemTableCudaIterator;
+ friend class MemTableCudaBackwardIterator;
+ friend __global__ void MemTableCudaAdd_(MemTableCuda *, size_t, char *);
+ friend __global__ void MemTableCudaGet_(MemTableCuda *, char *, char **, size_t* malloc_size);
+
+ struct KeyComparator {
+ const InternalKeyComparator comparator;
+ __device__ __host__ explicit KeyComparator(const InternalKeyComparator& c) : comparator(c) {}
+ __device__ int operator()(const char* a, const char* b) const;
+ __device__ __host__ ~KeyComparator() = default;
+ };
+
+ typedef SkipList<const char*, KeyComparator> Table;
+
+ __device__ Table::Iterator getIter() {
+ Table::Iterator iter(&this->table_);
+ return iter;
+ }
+
+ ~MemTableCuda(); // Private since only Unref() should be used to delete it
+
+ KeyComparator comparator_;
+ int refs_;
+ ArenaCuda arena_;
+ Table table_;
+};
+
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_MEMTABLE_H_