1 files changed, 245 insertions, 1 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