artdaq_core  v3_06_10
SharedMemoryManager.hh
1 #ifndef artdaq_core_Core_SharedMemoryManager_hh
2 #define artdaq_core_Core_SharedMemoryManager_hh 1
3 
4 #include <atomic>
5 #include <deque>
6 #include <list>
7 #include <mutex>
8 #include <string>
9 #include <vector>
10 #include "artdaq-core/Utilities/TimeUtils.hh"
11 
12 namespace artdaq {
18 {
19 public:
24  {
25  Empty,
26  Writing,
27  Full,
28  Reading
29  };
30 
36  static inline std::string FlagToString(BufferSemaphoreFlags flag)
37  {
38  switch (flag)
39  {
41  return "Empty";
43  return "Writing";
45  return "Full";
47  return "Reading";
48  }
49  return "Unknown";
50  }
51 
61  SharedMemoryManager(uint32_t shm_key, size_t buffer_count = 0, size_t buffer_size = 0, uint64_t buffer_timeout_us = 100 * 1000000, bool destructive_read_mode = true);
62 
66  virtual ~SharedMemoryManager() noexcept; // NOLINT(bugprone-exception-escape) See implementation for more details
67 
71  bool Attach(size_t timeout_usec = 0);
72 
77  int GetBufferForReading();
78 
84  int GetBufferForWriting(bool overwrite);
85 
90  bool ReadyForRead();
91 
97  virtual bool ReadyForWrite(bool overwrite);
98 
103  size_t ReadReadyCount();
104 
110  size_t WriteReadyCount(bool overwrite);
111 
117  std::deque<int> GetBuffersOwnedByManager(bool locked = true);
118 
124  size_t BufferDataSize(int buffer);
125 
130  size_t BufferSize() { return (shm_ptr_ != nullptr ? shm_ptr_->buffer_size : 0); }
131 
136  void ResetReadPos(int buffer);
137 
142  void ResetWritePos(int buffer);
148  void IncrementReadPos(int buffer, size_t read);
149 
156  bool IncrementWritePos(int buffer, size_t written);
157 
163  bool MoreDataInBuffer(int buffer);
164 
171  bool CheckBuffer(int buffer, BufferSemaphoreFlags flags);
172 
178  void MarkBufferFull(int buffer, int destination = -1);
179 
186  void MarkBufferEmpty(int buffer, bool force = false, bool detachOnException = true);
187 
194  bool ResetBuffer(int buffer);
195 
199  void GetNewId()
200  {
201  if (manager_id_ < 0 && IsValid()) manager_id_ = shm_ptr_->next_id.fetch_add(1);
202  }
203 
208  uint16_t GetAttachedCount() const;
209 
213  void ResetAttachedCount() const
214  {
215  if (manager_id_ == 0 && IsValid()) shm_ptr_->next_id = 1;
216  }
217 
222  int GetMyId() const { return manager_id_; }
223 
228  int GetRank() const { return IsValid() ? shm_ptr_->rank : -1; }
229 
234  void SetRank(int rank)
235  {
236  if (manager_id_ == 0 && IsValid()) shm_ptr_->rank = rank;
237  }
238 
243  bool IsValid() const { return shm_ptr_ ? true : false; }
244 
248  bool IsEndOfData() const;
249 
254  size_t size() const { return IsValid() ? shm_ptr_->buffer_count : 0; }
255 
263  size_t Write(int buffer, void* data, size_t size);
264 
272  bool Read(int buffer, void* data, size_t size);
273 
278  virtual std::string toString();
279 
284  uint32_t GetKey() const { return shm_key_; }
285 
291  void* GetReadPos(int buffer);
292 
298  void* GetWritePos(int buffer);
299 
305  void* GetBufferStart(int buffer);
306 
314  void Detach(bool throwException = false, const std::string& category = "", const std::string& message = "", bool force = false);
315 
320  uint64_t GetBufferTimeout() const { return IsValid() ? shm_ptr_->buffer_timeout_us : 0; }
321 
326  size_t GetBufferCount() const { return IsValid() ? shm_ptr_->next_sequence_id : 0; }
327 
332  size_t GetLastSeenBufferID() const { return last_seen_id_; }
333 
337  size_t GetLowestSeqIDRead() const { return IsValid() ? shm_ptr_->lowest_seq_id_read : 0; }
338 
343  void SetMinWriteSize(size_t size) { min_write_size_ = size; }
344 
349  std::vector<std::pair<int, BufferSemaphoreFlags>> GetBufferReport();
350 
354  void TouchBuffer(int buffer) { return touchBuffer_(getBufferInfo_(buffer)); }
355 
356 private:
357  SharedMemoryManager(SharedMemoryManager const&) = delete;
359  SharedMemoryManager& operator=(SharedMemoryManager const&) = delete;
360  SharedMemoryManager& operator=(SharedMemoryManager&&) = delete;
361 
362  struct ShmBuffer
363  {
364  size_t writePos;
365  size_t readPos;
366  std::atomic<BufferSemaphoreFlags> sem;
367  std::atomic<int16_t> sem_id;
368  std::atomic<size_t> sequence_id;
369  std::atomic<uint64_t> last_touch_time;
370  };
371 
372  struct ShmStruct
373  {
374  std::atomic<unsigned int> reader_pos;
375  std::atomic<unsigned int> writer_pos;
376  int buffer_count;
377  size_t buffer_size;
378  size_t buffer_timeout_us;
379  size_t next_sequence_id;
380  size_t lowest_seq_id_read;
381  bool destructive_read_mode;
382 
383  std::atomic<int> next_id;
384  int rank;
385  unsigned ready_magic;
386  };
387 
388  inline uint8_t* dataStart_() const
389  {
390  if (shm_ptr_ == nullptr) return nullptr;
391  return reinterpret_cast<uint8_t*>(shm_ptr_ + 1) + shm_ptr_->buffer_count * sizeof(ShmBuffer); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast,cppcoreguidelines-pro-bounds-pointer-arithmetic)
392  }
393 
394  inline uint8_t* bufferStart_(int buffer)
395  {
396  if (shm_ptr_ == nullptr) return nullptr;
397  if (buffer >= requested_shm_parameters_.buffer_count && buffer >= shm_ptr_->buffer_count) Detach(true, "ArgumentOutOfRange", "The specified buffer does not exist!");
398  return dataStart_() + buffer * shm_ptr_->buffer_size; // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
399  }
400 
401  inline ShmBuffer* getBufferInfo_(int buffer)
402  {
403  if (shm_ptr_ == nullptr) return nullptr;
404  // Check local variable first, but re-check shared memory
405  if (buffer >= requested_shm_parameters_.buffer_count && buffer >= shm_ptr_->buffer_count)
406  Detach(true, "ArgumentOutOfRange", "The specified buffer does not exist!");
407  return buffer_ptrs_[buffer];
408  }
409  bool checkBuffer_(ShmBuffer* buffer, BufferSemaphoreFlags flags, bool exceptions = true);
410  void touchBuffer_(ShmBuffer* buffer);
411 
412  ShmStruct requested_shm_parameters_;
413 
414  int shm_segment_id_;
415  ShmStruct* shm_ptr_;
416  uint32_t shm_key_;
417  int manager_id_;
418  std::vector<ShmBuffer*> buffer_ptrs_;
419  mutable std::vector<std::mutex> buffer_mutexes_;
420  mutable std::mutex search_mutex_;
421 
422  std::atomic<size_t> last_seen_id_;
423  size_t min_write_size_;
424 };
425 
426 } // namespace artdaq
427 
428 #endif // artdaq_core_Core_SharedMemoryManager_hh
void Detach(bool throwException=false, const std::string &category="", const std::string &message="", bool force=false)
Detach from the Shared Memory segment, optionally throwing a cet::exception with the specified proper...
void TouchBuffer(int buffer)
Touch the given buffer (update its last_touch_time)
bool Read(int buffer, void *data, size_t size)
Read size bytes of data from buffer into the given pointer.
void IncrementReadPos(int buffer, size_t read)
Increment the read position for a given buffer.
void ResetAttachedCount() const
Reset the attached manager count to 0.
bool IsValid() const
Is the shared memory pointer valid?
bool Attach(size_t timeout_usec=0)
Reconnect to the shared memory segment.
std::deque< int > GetBuffersOwnedByManager(bool locked=true)
Get the list of all buffers currently owned by this manager instance.
void ResetReadPos(int buffer)
Set the read position of the given buffer to the beginning of the buffer.
static std::string FlagToString(BufferSemaphoreFlags flag)
Convert a BufferSemaphoreFlags variable to its string represenatation.
bool MoreDataInBuffer(int buffer)
Determine if more data is available to be read, based on the read position and data size...
virtual std::string toString()
Write information about the SharedMemory to a string.
void GetNewId()
Assign a new ID to the current SharedMemoryManager, if one has not yet been assigned.
The buffer is full, and waiting for a reader.
std::vector< std::pair< int, BufferSemaphoreFlags > > GetBufferReport()
Get a report on the status of each buffer.
BufferSemaphoreFlags
The BufferSemaphoreFlags enumeration represents the different possible &quot;states&quot; of a given shared mem...
size_t BufferDataSize(int buffer)
Get the current size of the buffer&#39;s data.
size_t BufferSize()
Get the size of of a single buffer.
virtual ~SharedMemoryManager() noexcept
SharedMemoryManager Destructor.
The buffer is currently being read from.
The buffer is currently being written to.
The SharedMemoryManager creates a Shared Memory area which is divided into a number of fixed-size buf...
The buffer is empty, and waiting for a writer.
size_t ReadReadyCount()
Count the number of buffers that are ready for reading.
bool ResetBuffer(int buffer)
Resets the buffer from Reading to Full. This operation will only have an effect if performed by the o...
int GetRank() const
Get the rank of the owner of the Shared Memory (artdaq assigns rank to each artdaq process for data f...
size_t GetLowestSeqIDRead() const
Gets the lowest sequence ID that has been read by any reader, as reported by the readers.
size_t size() const
Get the number of buffers in the shared memory segment.
bool IncrementWritePos(int buffer, size_t written)
Increment the write position for a given buffer.
bool IsEndOfData() const
Determine whether the Shared Memory is marked for destruction (End of Data)
bool CheckBuffer(int buffer, BufferSemaphoreFlags flags)
Check both semaphore conditions (Mode flag and manager ID) for a given buffer.
size_t GetLastSeenBufferID() const
Gets the highest buffer number either written or read by this SharedMemoryManager.
uint32_t GetKey() const
Get the key of the shared memory attached to this SharedMemoryManager.
void MarkBufferFull(int buffer, int destination=-1)
Release a buffer from a writer, marking it Full and ready for a reader.
void MarkBufferEmpty(int buffer, bool force=false, bool detachOnException=true)
Release a buffer from a reader, marking it Empty and ready to accept more data.
uint64_t GetBufferTimeout() const
Gets the configured timeout for buffers to be declared &quot;stale&quot;.
void ResetWritePos(int buffer)
Set the write position of the given buffer to the beginning of the buffer.
void SetMinWriteSize(size_t size)
Sets the threshold after which a buffer should be considered &quot;non-empty&quot; (in case of default headers)...
size_t GetBufferCount() const
Gets the number of buffers which have been processed through the Shared Memory.
void * GetWritePos(int buffer)
Get a pointer to the current write position of the buffer.
size_t Write(int buffer, void *data, size_t size)
Write size bytes of data from the given pointer to a buffer.
void * GetReadPos(int buffer)
Get a pointer to the current read position of the buffer.
void * GetBufferStart(int buffer)
Get a pointer to the start position of the buffer.
SharedMemoryManager(uint32_t shm_key, size_t buffer_count=0, size_t buffer_size=0, uint64_t buffer_timeout_us=100 *1000000, bool destructive_read_mode=true)
SharedMemoryManager Constructor.
bool ReadyForRead()
Whether any buffer is ready for read.
void SetRank(int rank)
Set the rank stored in the Shared Memory, if the current instance is the owner of the shared memory...
int GetBufferForWriting(bool overwrite)
Finds a buffer that is ready to be written to, and reserves it for the calling manager.
uint16_t GetAttachedCount() const
Get the number of attached SharedMemoryManagers.
size_t WriteReadyCount(bool overwrite)
Count the number of buffers that are ready for writing.
int GetMyId() const
Get the ID number of the current SharedMemoryManager.
int GetBufferForReading()
Finds a buffer that is ready to be read, and reserves it for the calling manager. ...
virtual bool ReadyForWrite(bool overwrite)
Whether any buffer is available for write.