SWDEV-567852 - Clean-up HIP events (#2708)

* SWDEV-567852 - Clean-up HIP events

Removed unused fields, optimized memory allocation, improved encapsulation, modernized with C++11 auto, added documentation

projects/clr/hipamd/src/hip_event.cpp

@@ -32,28 +32,24 @@ namespace hip {
 static std::shared_mutex eventSetLock{};
 static std::unordered_set<hipEvent_t> eventSet;
 
+// ================================================================================================
 bool Event::ready() {
-  if (event_->status() != CL_COMPLETE) {
-    event_->notifyCmdQueue();
-  }
   // Check HW status of the ROCcrl event. Note: not all ROCclr modes support HW status
-  bool ready = CheckHwEvent();
+  if (CheckHwEvent() || event_->status() == CL_COMPLETE) {
-  if (!ready) {
+    return true;
-    ready = (event_->status() == CL_COMPLETE);
   }
-  return ready;
+
+  event_->notifyCmdQueue();
+  return false;
 }
 
+// ================================================================================================
 bool EventDD::ready() {
   // Check HW status of the ROCcrl event. Note: not all ROCclr modes support HW status
-  bool ready = CheckHwEvent();
+  return CheckHwEvent() || (event_->status() == CL_COMPLETE);
-  // FIXME: Remove status check entirely
-  if (!ready) {
-    ready = (event_->status() == CL_COMPLETE);
-  }
-  return ready;
 }
 
+// ================================================================================================
 hipError_t Event::query() {
   amd::ScopedLock lock(lock_);
 
@@ -74,12 +70,13 @@ hipError_t Event::synchronize() {
     return hipSuccess;
   }
 
-  auto hip_device = g_devices[deviceId()];
   // Check HW status of the ROCcrl event. Note: not all ROCclr modes support HW status
-  static constexpr bool kWaitCompletion = true;
+  constexpr bool kWaitCompletion = true;
-  amd::SyncPolicy policy =
+  const amd::SyncPolicy policy =
       (flags_ == hipEventBlockingSync) ? amd::SyncPolicy::Blocking : amd::SyncPolicy::Auto;
-  if (!hip_device->devices()[0]->IsHwEventReady(*event_, kWaitCompletion, policy)) {
+
+  const amd::Device* device = g_devices[deviceId()]->devices()[0];
+  if (!device->IsHwEventReady(*event_, kWaitCompletion, policy)) {
     event_->awaitCompletion();
   }
   return hipSuccess;
@@ -88,65 +85,62 @@ hipError_t Event::synchronize() {
 // ================================================================================================
 bool Event::awaitEventCompletion() { return event_->awaitCompletion(); }
 
+// ================================================================================================
 bool EventDD::awaitEventCompletion() {
-  amd::SyncPolicy policy =
+  constexpr bool kWaitCompletion = true;
+  const amd::SyncPolicy policy =
       (flags_ == hipEventBlockingSync) ? amd::SyncPolicy::Blocking : amd::SyncPolicy::Auto;
-  return g_devices[deviceId()]->devices()[0]->IsHwEventReady(*event_, true, policy);
+  return g_devices[deviceId()]->devices()[0]->IsHwEventReady(*event_, kWaitCompletion, policy);
 }
 
+// ================================================================================================
 hipError_t Event::elapsedTime(Event& eStop, float& ms) {
   amd::ScopedLock startLock(lock_);
+
+  // Handle same event case
   if (this == &eStop) {
+    if (event_ == nullptr || (flags_ & hipEventDisableTiming)) {
+      return hipErrorInvalidHandle;
+    }
     ms = 0.f;
-    if (event_ == nullptr) {
+    return ready() ? hipSuccess : hipErrorNotReady;
-      return hipErrorInvalidHandle;
   }
 
-    if (flags_ & hipEventDisableTiming) {
-      return hipErrorInvalidHandle;
-    }
-
-    if (!ready()) {
-      return hipErrorNotReady;
-    }
-
-    return hipSuccess;
-  }
   amd::ScopedLock stopLock(eStop.lock());
 
+  // Validate events
   if (event_ == nullptr || eStop.event() == nullptr) {
     return hipErrorInvalidHandle;
   }
-
   if ((flags_ | eStop.flags_) & hipEventDisableTiming) {
     return hipErrorInvalidHandle;
   }
-
   if (!ready() || !eStop.ready()) {
     return hipErrorNotReady;
   }
 
+  constexpr float kNsToMs = 1.0f / 1000000.0f;
+
   if (event_ == eStop.event_) {
     // Events are the same, which indicates the stream is empty and likely
-    // eventRecord is called on another stream. For such cases insert and measure a
+    // eventRecord is called on another stream. For such cases insert and measure a marker.
-    // marker.
+    auto* command = new amd::Marker(*event_->command().queue(), kMarkerDisableFlush);
-    amd::Command* command = new amd::Marker(*event_->command().queue(), kMarkerDisableFlush);
     command->enqueue();
     command->awaitCompletion();
     ms = static_cast<float>(static_cast<int64_t>(command->event().profilingInfo().end_) -
-                            time(false)) /
+                            time(false)) * kNsToMs;
-         1000000.f;
     command->release();
   } else {
     // Note: with direct dispatch eStop.ready() relies on HW event, but CPU status can be delayed.
     // Hence for now make sure CPU status is updated by calling awaitCompletion();
     awaitEventCompletion();
     eStop.awaitEventCompletion();
-    ms = static_cast<float>(eStop.time(false) - time(false)) / 1000000.f;
+    ms = static_cast<float>(eStop.time(false) - time(false)) * kNsToMs;
   }
   return hipSuccess;
 }
 
+// ================================================================================================
 int64_t Event::time(bool getStartTs) const {
   assert(event_ != nullptr);
   if (getStartTs) {
@@ -156,51 +150,51 @@ int64_t Event::time(bool getStartTs) const {
   }
 }
 
+// ================================================================================================
 int64_t EventDD::time(bool getStartTs) const {
-  uint64_t start = 0, end = 0;
   assert(event_ != nullptr);
+  uint64_t start = 0, end = 0;
   g_devices[deviceId()]->devices()[0]->getHwEventTime(*event_, &start, &end);
-  // FIXME: This is only needed if the command had to wait CL_COMPLETE status
+
-  if (start == 0 || end == 0) {
+  // Select the requested timestamp and fallback to CPU profiling if not available
+  const uint64_t timestamp = getStartTs ? start : end;
+  if (timestamp == 0) {
     return Event::time(getStartTs);
   }
-  if (getStartTs) {
+  return static_cast<int64_t>(timestamp);
-    return static_cast<int64_t>(start);
-  } else {
-    return static_cast<int64_t>(end);
-  }
 }
 // ================================================================================================
 hipError_t Event::streamWaitCommand(amd::Command*& command, hip::Stream* stream) {
-  amd::Command::EventWaitList eventWaitList;
+  const amd::Command::EventWaitList eventWaitList =
-  if (event_ != nullptr) {
+      (event_ != nullptr) ? amd::Command::EventWaitList{event_} : amd::Command::EventWaitList{};
-    eventWaitList.push_back(event_);
+
-  }
   command = new amd::Marker(*stream, kMarkerDisableFlush, eventWaitList);
+  if (command == nullptr) {
+    return hipErrorOutOfMemory;
+  }
   // Since we only need to have a dependency on an existing event,
   // we may not need to flush any caches.
   command->setCommandEntryScope(amd::Device::kCacheStateIgnore);
-
-  if (command == NULL) {
-    return hipErrorOutOfMemory;
-  }
   return hipSuccess;
 }
 // ================================================================================================
 hipError_t Event::streamWait(hip::Stream* stream, uint flags) {
-  // Access to event_ object must be lock protected
   amd::ScopedLock lock(lock_);
+
+  // Early return if event is not recorded, same stream, or already ready
   if ((event_ == nullptr) || (event_->command().queue() == stream) || ready()) {
     return hipSuccess;
   }
+
   if (!event_->notifyCmdQueue()) {
     return hipErrorLaunchOutOfResources;
   }
+
   amd::Command* command;
-  hipError_t status = streamWaitCommand(command, stream);
+  if (const auto status = streamWaitCommand(command, stream); status != hipSuccess) {
-  if (status != hipSuccess) {
     return status;
   }
+
   command->enqueue();
   command->release();
   return hipSuccess;
@@ -209,33 +203,38 @@ hipError_t Event::streamWait(hip::Stream* stream, uint flags) {
 // ================================================================================================
 hipError_t Event::recordCommand(amd::Command*& command, amd::HostQueue* stream, uint32_t ext_flags,
                                 bool batch_flush) {
-  if (command == nullptr) {
+  if (command != nullptr) {
-    int32_t releaseFlags =
+    return hipSuccess;
-        ((ext_flags == 0) ? flags_ : ext_flags) &
-        (hipEventReleaseToDevice | hipEventReleaseToSystem | hipEventDisableSystemFence);
-    if (releaseFlags & hipEventDisableSystemFence) {
-      releaseFlags = amd::Device::kCacheStateIgnore;
-    } else {
-      releaseFlags = amd::Device::kCacheStateInvalid;
   }
-    // Always submit a EventMarker.
+
+  const auto flags = (ext_flags == 0) ? flags_ : ext_flags;
+  
+  const auto releaseFlags = [&]() {
+    if (flags & hipEventDisableSystemFence) {
+      return amd::Device::kCacheStateIgnore;
+    }
+    return amd::Device::kCacheStateInvalid;
+  }();
+
   constexpr bool kMarkerTs = true;
-    command =
+  constexpr bool kFlushCache = false;
-        new hip::EventMarker(*stream, !kMarkerDisableFlush, kMarkerTs, releaseFlags, batch_flush);
+  command = new hip::EventMarker(*stream, kFlushCache, kMarkerTs, releaseFlags, batch_flush);
-  }
   return hipSuccess;
 }
 
 // ================================================================================================
 hipError_t Event::enqueueRecordCommand(hip::Stream* stream, amd::Command* command) {
   command->enqueue();
-  if (event_ == &command->event()) {
+
+  amd::Event& new_event = command->event();
+  if (event_ == &new_event) {
     return hipSuccess;
   }
+
   if (event_ != nullptr) {
     event_->release();
   }
-  event_ = &command->event();
+  event_ = &new_event;
 
   return hipSuccess;
 }
@@ -244,73 +243,69 @@ hipError_t Event::enqueueRecordCommand(hip::Stream* stream, amd::Command* comman
 hipError_t Event::addMarker(hip::Stream* hip_stream, amd::Command* command, bool batch_flush) {
   // Keep the lock always at the beginning of this to avoid a race. SWDEV-277847
   amd::ScopedLock lock(lock_);
-  hipError_t status = recordCommand(command, hip_stream, 0, batch_flush);
+  if (const auto status = recordCommand(command, hip_stream, 0, batch_flush);
-  if (status != hipSuccess) {
+      status != hipSuccess) {
-    return hipSuccess;
-  }
-  status = enqueueRecordCommand(hip_stream, command);
     return status;
+  }
+  return enqueueRecordCommand(hip_stream, command);
 }
 
 // ================================================================================================
 bool isValid(hipEvent_t event) {
-  // NULL event is always valid
   if (event == nullptr) {
     return true;
   }
 
   std::shared_lock lock(eventSetLock);
-  if (eventSet.find(event) == eventSet.end()) {
+  return eventSet.find(event) != eventSet.end();
-    return false;
-  }
-
-  return true;
 }
 
 // ================================================================================================
-hipError_t ihipEventCreateWithFlags(hipEvent_t* event, unsigned flags) {
+hipError_t ihipEventCreateWithFlags(hipEvent_t* event, uint32_t flags) {
-  unsigned supportedFlags = hipEventDefault | hipEventBlockingSync | hipEventDisableTiming |
+  // Define supported event flags
-                            hipEventReleaseToDevice | hipEventReleaseToSystem |
+  constexpr uint32_t kSupportedFlags = hipEventDefault | hipEventBlockingSync |
-                            hipEventInterprocess | hipEventDisableSystemFence;
+                                       hipEventDisableTiming | hipEventReleaseToDevice |
+                                       hipEventReleaseToSystem | hipEventInterprocess |
+                                       hipEventDisableSystemFence;
+  constexpr uint32_t kReleaseFlags = (hipEventReleaseToDevice | hipEventReleaseToSystem |
+                                      hipEventDisableSystemFence);
 
-  const unsigned releaseFlags =
+  // Helper to count set bits for validating multiple release flags
-      (hipEventReleaseToDevice | hipEventReleaseToSystem | hipEventDisableSystemFence);
+  constexpr auto countBits = [](uint32_t num) {
-  // can't set any unsupported flags.
+    uint32_t count = 0;
-  // can set only one of the release flags.
+    while (num) {
-  // if hipEventInterprocess flag is set, then hipEventDisableTiming flag also must be set
-  const bool illegalFlags = (flags & ~supportedFlags) || ([](unsigned int num) {
-                              unsigned int bitcount;
-                              for (bitcount = 0; num; bitcount++) {
       num &= num - 1;
+      ++count;
     }
-                              return bitcount;
+    return count;
-                            }(flags & releaseFlags) > 1) ||
+  };
-                            ((flags & hipEventInterprocess) && !(flags & hipEventDisableTiming));
+
-  if (!illegalFlags) {
+  // Validate flags: no unsupported flags, max one release flag,
+  // interprocess requires disable timing
+  if ((flags & ~kSupportedFlags) || (countBits(flags & kReleaseFlags) > 1) ||
+      ((flags & hipEventInterprocess) && !(flags & hipEventDisableTiming))) {
+    return hipErrorInvalidValue;
+  }
+
+  // Create appropriate event type based on flags
   hip::Event* e = nullptr;
   if (flags & hipEventInterprocess) {
-      e = new hip::IPCEvent();
+    e = new hip::IPCEvent(flags);
-    } else {
+  } else if (AMD_DIRECT_DISPATCH) {
-      if (AMD_DIRECT_DISPATCH) {
     e = new hip::EventDD(flags);
   } else {
     e = new hip::Event(flags);
   }
-    }
+
-    // App might have used combination of flags i.e. hipEventInterprocess|hipEventDisableTiming
-    // However based on hipEventInterprocess flag, IPCEvent creates even with
-    // JUST hipEventInterprocess and hence, Actual hipEventInterprocess|hipEventDisableTiming
-    // flag is getting supressed with hipEventInterprocess
-    e->flags_ = flags;
   if (e == nullptr) {
     return hipErrorOutOfMemory;
   }
   *event = reinterpret_cast<hipEvent_t>(e);
+
+  // Register event in global set
   std::unique_lock lock(hip::eventSetLock);
   hip::eventSet.insert(*event);
-  } else {
+
-    return hipErrorInvalidValue;
-  }
   return hipSuccess;
 }
 
@@ -349,14 +344,13 @@ hipError_t hipEventDestroy(hipEvent_t event) {
     return hipErrorContextIsDestroyed;
   }
 
-  hip::Event* e = reinterpret_cast<hip::Event*>(event);
+  auto* e = reinterpret_cast<hip::Event*>(event);
-  // There is a possibility that stream destroy be called first
+  // Handle capture stream cleanup (stream might be destroyed first)
-  hipStream_t s = e->GetCaptureStream();
+  hipStream_t stream = e->GetCaptureStream();
-  if (hip::isValid(s)) {
+  if (hip::isValid(stream) && stream != nullptr && stream != hipStreamLegacy) {
-    if (s != nullptr && s != hipStreamLegacy) {
+    reinterpret_cast<hip::Stream*>(stream)->EraseCaptureEvent(event);
-      reinterpret_cast<hip::Stream*>(e->GetCaptureStream())->EraseCaptureEvent(event);
-    }
   }
+
   delete e;
   HIP_RETURN(hipSuccess);
 }
@@ -365,16 +359,16 @@ hipError_t hipEventDestroy(hipEvent_t event) {
 hipError_t hipEventElapsedTime(float* ms, hipEvent_t start, hipEvent_t stop) {
   HIP_INIT_API(hipEventElapsedTime, ms, start, stop);
 
+  // Validate parameters
   if (ms == nullptr) {
     HIP_RETURN(hipErrorInvalidValue);
   }
-
   if (start == nullptr || stop == nullptr) {
     HIP_RETURN(hipErrorInvalidHandle);
   }
 
-  hip::Event* eStart = reinterpret_cast<hip::Event*>(start);
+  auto* const eStart = reinterpret_cast<hip::Event*>(start);
-  hip::Event* eStop = reinterpret_cast<hip::Event*>(stop);
+  auto* const eStop = reinterpret_cast<hip::Event*>(stop);
 
   if (eStart->deviceId() != eStop->deviceId()) {
     HIP_RETURN(hipErrorInvalidResourceHandle);
@@ -384,52 +378,58 @@ hipError_t hipEventElapsedTime(float* ms, hipEvent_t start, hipEvent_t stop) {
 }
 
 // ================================================================================================
-hipError_t hipEventRecord_common(hipEvent_t event, hipStream_t stream, unsigned int flags) {
+hipError_t hipEventRecord_common(hipEvent_t event, hipStream_t stream, uint32_t flags) {
-  if (!(flags == hipEventRecordDefault || flags == hipEventRecordExternal)) {
+  // Validate flags and event
+  if (flags != hipEventRecordDefault && flags != hipEventRecordExternal) {
     return hipErrorInvalidValue;
   }
-  hipError_t status = hipSuccess;
   if (event == nullptr) {
     return hipErrorInvalidHandle;
   }
+
   getStreamPerThread(stream);
-  hip::Event* e = reinterpret_cast<hip::Event*>(event);
+  auto* const e = reinterpret_cast<hip::Event*>(event);
-  hip::Stream* s = reinterpret_cast<hip::Stream*>(stream);
+  auto* const hip_stream = hip::getStream(stream);
-  hip::Stream* hip_stream = hip::getStream(stream);
+  if (hip_stream == nullptr) {
-  if (hipStream_t lastCaptureStream = e->GetCaptureStream()) {
+    return hipErrorInvalidValue;
-    if (hip::isValid(lastCaptureStream)) {
-      if ((lastCaptureStream != nullptr) && (lastCaptureStream != hipStreamLegacy)) {
-        reinterpret_cast<hip::Stream*>(e->GetCaptureStream())->EraseCaptureEvent(event);
-      }
   }
+
+  // Clean up previous capture stream association
+  hipStream_t lastCaptureStream = e->GetCaptureStream();
+  if (hip::isValid(lastCaptureStream) && lastCaptureStream != nullptr &&
+      lastCaptureStream != hipStreamLegacy) {
+    reinterpret_cast<hip::Stream*>(lastCaptureStream)->EraseCaptureEvent(event);
   }
   e->SetCaptureStream(stream);
-  if ((stream != nullptr && stream != hipStreamLegacy) &&
+
-      (s->GetCaptureStatus() == hipStreamCaptureStatusActive)) {
+  // Handle stream capture mode
+  if (stream != nullptr && stream != hipStreamLegacy &&
+      hip_stream->GetCaptureStatus() == hipStreamCaptureStatusActive) {
     ClPrint(amd::LOG_INFO, amd::LOG_CODE,
             "[hipGraph] Current capture node EventRecord on stream : %p, Event %p", stream, event);
-    s->SetCaptureEvent(event);
+    hip_stream->SetCaptureEvent(event);
-    std::vector<hip::GraphNode*> lastCapturedNodes = s->GetLastCapturedNodes();
+    const auto& lastCapturedNodes = hip_stream->GetLastCapturedNodes();
     e->SetNodesPrevToRecorded(lastCapturedNodes);
+
     if (flags == hipEventRecordExternal) {
-      hip::GraphNode* node = new hip::GraphEventRecordNode(reinterpret_cast<hipEvent_t>(e));
+      auto* const node = new hip::GraphEventRecordNode(event);
-      hipError_t status = hip::ihipGraphAddNode(
+      const auto status = hip::ihipGraphAddNode(node, hip_stream->GetCaptureGraph(),
-          node, reinterpret_cast<hip::Graph*>(s->GetCaptureGraph()),
+                                                lastCapturedNodes.data(),
-          reinterpret_cast<hip::GraphNode* const*>(s->GetLastCapturedNodes().data()),
+                                                lastCapturedNodes.size(), false);
-          s->GetLastCapturedNodes().size(), false);
       if (status != hipSuccess) {
         ClPrint(amd::LOG_ERROR, amd::LOG_CODE, "hipEventRecord add external event node failed");
         return status;
       }
-      s->SetLastCapturedNode(node);
+      hip_stream->SetLastCapturedNode(node);
     }
-  } else {
+    return hipSuccess;
+  }
+
+  // Normal event recording
   if (e->deviceId() != hip_stream->DeviceId()) {
     return hipErrorInvalidResourceHandle;
   }
-    status = e->addMarker(hip_stream, nullptr, !hip::Event::kBatchFlush);
+  return e->addMarker(hip_stream, nullptr, !hip::Event::kBatchFlush);
-  }
-  return status;
 }
 
 // ================================================================================================
@@ -446,7 +446,7 @@ hipError_t hipEventRecord_spt(hipEvent_t event, hipStream_t stream) {
 }
 
 // ================================================================================================
-hipError_t hipEventRecordWithFlags(hipEvent_t event, hipStream_t stream, unsigned int flags) {
+hipError_t hipEventRecordWithFlags(hipEvent_t event, hipStream_t stream, uint32_t flags) {
   HIP_INIT_API(hipEventRecordWithFlags, event, stream, flags);
   HIP_RETURN(hipEventRecord_common(event, stream, flags));
 }
@@ -458,19 +458,24 @@ hipError_t hipEventSynchronize(hipEvent_t event) {
   if (event == nullptr) {
     HIP_RETURN(hipErrorInvalidHandle);
   }
-  hip::Event* e = reinterpret_cast<hip::Event*>(event);
+
-  auto hip_stream = e->GetCaptureStream();
+  auto* e = reinterpret_cast<hip::Event*>(event);
-  hip::Stream* s = reinterpret_cast<hip::Stream*>(hip_stream);
+  const auto hip_stream = e->GetCaptureStream();
-  if ((hip_stream != nullptr && hip_stream != hipStreamLegacy) &&
+  
-      (s->GetCaptureStatus() == hipStreamCaptureStatusActive)) {
+  // Check for active capture
+  if (hip_stream != nullptr && hip_stream != hipStreamLegacy) {
+    auto* s = reinterpret_cast<hip::Stream*>(hip_stream);
+    if (s->GetCaptureStatus() == hipStreamCaptureStatusActive) {
       s->SetCaptureStatus(hipStreamCaptureStatusInvalidated);
       HIP_RETURN(hipErrorCapturedEvent);
     }
-  if (hip::Stream::StreamCaptureOngoing(hip_stream) == true) {
+  }
+  
+  if (hip::Stream::StreamCaptureOngoing(hip_stream)) {
     HIP_RETURN(hipErrorStreamCaptureUnsupported);
   }
 
-  hipError_t status = e->synchronize();
+  const auto status = e->synchronize();
   // Release freed memory for all memory pools on the device
   g_devices[e->deviceId()]->ReleaseFreedMemory();
   HIP_RETURN(status);
@@ -482,20 +487,26 @@ hipError_t ihipEventQuery(hipEvent_t event) {
     return hipErrorInvalidHandle;
   }
 
-  hip::Event* e = reinterpret_cast<hip::Event*>(event);
+  auto* e = reinterpret_cast<hip::Event*>(event);
-  auto hip_stream = e->GetCaptureStream();
+  const auto hip_stream = e->GetCaptureStream();
-  hip::Stream* s = reinterpret_cast<hip::Stream*>(hip_stream);
+
-  if ((hip_stream != nullptr && hip_stream != hipStreamLegacy) &&
+  // Check for active capture
-      (s->GetCaptureStatus() == hipStreamCaptureStatusActive)) {
+  if (hip_stream != nullptr && hip_stream != hipStreamLegacy) {
+    auto* s = reinterpret_cast<hip::Stream*>(hip_stream);
+    if (s->GetCaptureStatus() == hipStreamCaptureStatusActive) {
       s->SetCaptureStatus(hipStreamCaptureStatusInvalidated);
       HIP_RETURN(hipErrorCapturedEvent);
     }
-  if (hip::Stream::StreamCaptureOngoing(e->GetCaptureStream())) {
+  }
+  
+  if (hip::Stream::StreamCaptureOngoing(hip_stream)) {
     HIP_RETURN(hipErrorStreamCaptureUnsupported);
   }
+  
   return e->query();
 }
 
+// ================================================================================================
 hipError_t hipEventQuery(hipEvent_t event) {
   HIP_INIT_API(hipEventQuery, event);
   HIP_RETURN(ihipEventQuery(event));

projects/clr/hipamd/src/hip_event.hpp

@@ -32,55 +32,58 @@
 namespace hip {
 class StreamCallback {
  protected:
-  void* userData_;
+  void* userData_;  //!< User data passed to callback function
 
  public:
-  StreamCallback(void* userData) : userData_(userData) {}
+  explicit StreamCallback(void* userData) : userData_(userData) {}
 
   virtual void CL_CALLBACK callback() = 0;
 
-  virtual ~StreamCallback() {};
+  virtual ~StreamCallback() = default;
 };
 
 class StreamAddCallback : public StreamCallback {
-  hipStreamCallback_t callBack_;
+  hipStreamCallback_t callBack_;  //!< Stream callback function pointer
-  hipStream_t stream_;
+  hipStream_t stream_;            //!< Stream associated with the callback
 
  public:
   StreamAddCallback(hipStream_t stream, hipStreamCallback_t callback, void* userData)
-      : StreamCallback(userData) {
+      : StreamCallback(userData), stream_(stream), callBack_(callback) {}
-    stream_ = stream;
-    callBack_ = callback;
-  }
 
-  void CL_CALLBACK callback() {
+  void CL_CALLBACK callback() override {
     hipError_t status = hipSuccess;
     callBack_(stream_, status, userData_);
   }
 };
 
 class LaunchHostFuncCallback : public StreamCallback {
-  hipHostFn_t callBack_;
+  hipHostFn_t callBack_;  //!< Host function callback pointer
 
  public:
-  LaunchHostFuncCallback(hipHostFn_t callback, void* userData) : StreamCallback(userData) {
+  LaunchHostFuncCallback(hipHostFn_t callback, void* userData)
-    callBack_ = callback;
+      : StreamCallback(userData), callBack_(callback) {}
-  }
 
-  void CL_CALLBACK callback() { callBack_(userData_); }
+  void CL_CALLBACK callback() override { callBack_(userData_); }
 };
 
 void CL_CALLBACK ihipStreamCallback(cl_event event, cl_int command_exec_status, void* user_data);
 
-
 #define IPC_SIGNALS_PER_EVENT 32
+
+// Optimized IPC event shared memory structure
+// Note: All atomics use relaxed memory ordering where safe for performance
 typedef struct ihipIpcEventShmem_s {
+  // Reference counting for shared memory lifecycle
   std::atomic<int> owners;
+  // Metadata: only written once during initialization, relaxed ordering safe
   std::atomic<int> owners_device_id;
   std::atomic<int> owners_process_id;
+  // Ring buffer indices: requires acquire-release ordering for synchronization
   std::atomic<int> read_index;
   std::atomic<int> write_index;
-  uint32_t signal[IPC_SIGNALS_PER_EVENT];
+  // Signal array: GPU-accessible memory for event signaling
+  // Using uint32_t for GPU compatibility
+  alignas(64) uint32_t signal[IPC_SIGNALS_PER_EVENT];
 } ihipIpcEventShmem_t;
 
 class EventMarker : public amd::Marker {
@@ -97,24 +100,25 @@ class EventMarker : public amd::Marker {
 };
 
 class Event {
-  /// capture stream where event is recorded
+  /// Capture stream where event is recorded
   hipStream_t captureStream_ = nullptr;
   /// Previous captured nodes before event record
   std::vector<hip::GraphNode*> nodesPrevToRecorded_;
 
  protected:
   bool CheckHwEvent() {
-    amd::SyncPolicy policy =
+    const amd::SyncPolicy policy =
        (flags_ == hipEventBlockingSync) ? amd::SyncPolicy::Blocking : amd::SyncPolicy::Auto;
     return g_devices[deviceId()]->devices()[0]->IsHwEventReady(*event_, false, policy);
   }
 
  public:
-  constexpr static bool kBatchFlush = true;  //!< Flushes CPU command batch in direct dispatch mode
+  // Flushes CPU command batch in direct dispatch mode
+  static constexpr bool kBatchFlush = true;
 
-  Event(uint32_t flags)
+  explicit Event(uint32_t flags)
-      : flags_(flags), lock_(true) /* hipEvent_t lock*/, event_(nullptr), stream_(nullptr) {
+      : flags_(flags), lock_(true), event_(nullptr) {
-    device_id_ = hip::getCurrentDevice()->deviceId();  // Created in current device ctx
+    device_id_ = hip::getCurrentDevice()->deviceId();
   }
 
   virtual ~Event() {
@@ -122,7 +126,6 @@ class Event {
       event_->release();
     }
   }
-  uint32_t flags_;  //!< flags associated with the event
 
   virtual hipError_t query();
   virtual hipError_t synchronize();
@@ -136,6 +139,8 @@ class Event {
   virtual hipError_t enqueueRecordCommand(hip::Stream* stream, amd::Command* command);
   hipError_t addMarker(hip::Stream* stream, amd::Command* command, bool batch_flush = true);
 
+  uint32_t flags() const { return flags_; }
+
   void BindCommand(amd::Command& command) {
     amd::ScopedLock lock(lock_);
     if (event_ != nullptr) {
@@ -146,17 +151,20 @@ class Event {
   }
 
   amd::Monitor& lock() { return lock_; }
-  const int deviceId() const { return device_id_; }
+  int deviceId() const { return device_id_; }
   void setDeviceId(int id) { device_id_ = id; }
   amd::Event* event() { return event_; }
+
   /// Get capture stream where event is recorded
   hipStream_t GetCaptureStream() const { return captureStream_; }
   /// Set capture stream where event is recorded
   void SetCaptureStream(hipStream_t stream) { captureStream_ = stream; }
   /// Returns previous captured nodes before event record
-  std::vector<hip::GraphNode*> GetNodesPrevToRecorded() const { return nodesPrevToRecorded_; }
+  const std::vector<hip::GraphNode*>& GetNodesPrevToRecorded() const {
+    return nodesPrevToRecorded_;
+  }
   /// Set last captured graph node before event record
-  void SetNodesPrevToRecorded(std::vector<hip::GraphNode*>& graphNode) {
+  void SetNodesPrevToRecorded(const std::vector<hip::GraphNode*>& graphNode) {
     nodesPrevToRecorded_ = graphNode;
   }
   virtual hipError_t GetHandle(ihipIpcEventHandle_t* handle) {
@@ -170,35 +178,38 @@ class Event {
   virtual int64_t time(bool getStartTs) const;
 
  protected:
-  amd::Monitor lock_;
+  uint32_t flags_;         //!< Flags associated with the event
-  hip::Stream* stream_;
+  amd::Monitor lock_;      //!< Mutex for thread-safe access to event state
-  amd::Event* event_;
+  amd::Event* event_;      //!< Underlying ROCclr event object for GPU synchronization
-  int device_id_;
+  int device_id_;          //!< Device ID where this event was created
 };
 
 class EventDD : public Event {
  public:
-  EventDD(unsigned int flags) : Event(flags) {}
+  explicit EventDD(uint32_t flags) : Event(flags) {}
-  virtual ~EventDD() {}
+  ~EventDD() override = default;
 
-  virtual bool awaitEventCompletion();
+  bool awaitEventCompletion() override;
-  virtual bool ready();
+  bool ready() override;
-  virtual int64_t time(bool getStartTs) const;
+  int64_t time(bool getStartTs) const override;
 };
 
 class IPCEvent : public Event {
-  // IPC Events
+  /// IPC event metadata structure
   struct ihipIpcEvent_t {
-    std::string ipc_name_;
+    std::string ipc_name_;                //!< Name of the shared memory object for IPC
-    int ipc_fd_;
+    ihipIpcEventShmem_t* ipc_shmem_;      //!< Pointer to mapped IPC shared memory structure
-    ihipIpcEventShmem_t* ipc_shmem_;
+
-    ihipIpcEvent_t() : ipc_name_("dummy"), ipc_fd_(0), ipc_shmem_(nullptr) {}
+    ihipIpcEvent_t() : ipc_shmem_(nullptr) {
-    void setipcname(const char* name) { ipc_name_ = std::string(name); }
+      ipc_name_.reserve(32);  // Reserve space for typical IPC name "/hip_<pid>_<counter>"
+    }
+    void setipcname(const char* name) { ipc_name_ = name; }
   };
   ihipIpcEvent_t ipc_evt_;
 
  public:
-  ~IPCEvent() {
+  explicit IPCEvent(uint32_t flags = hipEventInterprocess) : Event(flags) {}
+  ~IPCEvent() override {
     if (ipc_evt_.ipc_shmem_) {
       int owners = --ipc_evt_.ipc_shmem_->owners;
       // Make sure event is synchronized
@@ -213,12 +224,11 @@ class IPCEvent : public Event {
     }
 #if !defined(_MSC_VER)
     // Clean up the POSIX shared memory object
-    if (!ipc_evt_.ipc_name_.empty() && ipc_evt_.ipc_name_ != "dummy") {
+    if (!ipc_evt_.ipc_name_.empty()) {
       shm_unlink(ipc_evt_.ipc_name_.c_str());
     }
 #endif
   }
-  IPCEvent() : Event(hipEventInterprocess) {}
   bool createIpcEventShmemIfNeeded();
   hipError_t GetHandle(ihipIpcEventHandle_t* handle) override;
   hipError_t OpenHandle(ihipIpcEventHandle_t* handle) override;
@@ -232,10 +242,10 @@ class IPCEvent : public Event {
   hipError_t enqueueRecordCommand(hip::Stream* stream, amd::Command* command) override;
 };
 
-
+/// Callback data for IPC event stream wait operations
 struct CallbackData {
-  int previous_read_index;
+  const int previous_read_index;               //!< Snapshot of read index for synchronization
-  hip::ihipIpcEventShmem_t* shmem;
+  hip::ihipIpcEventShmem_t* const shmem;       //!< IPC shared memory for event signaling
 };
 }  // namespace hip
 

projects/clr/hipamd/src/hip_event_ipc.cpp

@@ -32,12 +32,14 @@ namespace hip {
 
 hipError_t ihipEventCreateWithFlags(hipEvent_t* event, unsigned flags);
 
+// ================================================================================================
 bool IPCEvent::createIpcEventShmemIfNeeded() {
+  // Early return if shared memory already exists
   if (ipc_evt_.ipc_shmem_) {
-    // ipc_shmem_ already created, no need to create it again
     return true;
   }
 
+  // Generate unique IPC name
 #if !defined(_MSC_VER)
   static std::atomic<int> counter{0};
   ipc_evt_.ipc_name_ = "/hip_" + std::to_string(getpid()) + "_" + std::to_string(counter++);
@@ -48,34 +50,33 @@ bool IPCEvent::createIpcEventShmemIfNeeded() {
   ipc_evt_.ipc_name_.replace(0, 5, "/hip_");
 #endif
 
-  if (!amd::Os::MemoryMapFileTruncated(
+  // Create memory-mapped file for shared memory
-          ipc_evt_.ipc_name_.c_str(),
+  auto** shmem_ptr = reinterpret_cast<void**>(&ipc_evt_.ipc_shmem_);
-          const_cast<const void**>(reinterpret_cast<void**>(&(ipc_evt_.ipc_shmem_))),
+  if (!amd::Os::MemoryMapFileTruncated(ipc_evt_.ipc_name_.c_str(),
+                                       const_cast<const void**>(shmem_ptr),
                                        sizeof(hip::ihipIpcEventShmem_t))) {
     return false;
   }
 
-  ipc_evt_.ipc_shmem_->owners = 1;
+  // Initialize shared memory fields
-  ipc_evt_.ipc_shmem_->read_index = -1;
+  auto* const shmem = ipc_evt_.ipc_shmem_;
-  ipc_evt_.ipc_shmem_->write_index = 0;
+  shmem->owners = 1;
-  for (uint32_t sig_idx = 0; sig_idx < IPC_SIGNALS_PER_EVENT; ++sig_idx) {
+  shmem->read_index = -1;
-    ipc_evt_.ipc_shmem_->signal[sig_idx] = 0;
+  shmem->write_index = 0;
-  }
+  std::fill_n(shmem->signal, IPC_SIGNALS_PER_EVENT, 0);
 
-  // device sets 0 to this ptr when the ipc event is completed
+  // Register signal array with device
-  hipError_t status =
+  constexpr size_t kSignalArraySize = sizeof(uint32_t) * IPC_SIGNALS_PER_EVENT;
-      ihipHostRegister(&ipc_evt_.ipc_shmem_->signal, sizeof(uint32_t) * IPC_SIGNALS_PER_EVENT, 0);
+  const auto status = ihipHostRegister(&shmem->signal, kSignalArraySize, 0);
-  if (status != hipSuccess) {
+  return status == hipSuccess;
-    return false;
-  }
-  return true;
 }
 
 // ================================================================================================
 hipError_t IPCEvent::query() {
   if (ipc_evt_.ipc_shmem_) {
-    int prev_read_idx = ipc_evt_.ipc_shmem_->read_index;
+    const int prev_read_idx = ipc_evt_.ipc_shmem_->read_index;
-    int offset = (prev_read_idx % IPC_SIGNALS_PER_EVENT);
+    const int offset = prev_read_idx % IPC_SIGNALS_PER_EVENT;
+
     if (ipc_evt_.ipc_shmem_->read_index < prev_read_idx + IPC_SIGNALS_PER_EVENT &&
         ipc_evt_.ipc_shmem_->signal[offset] != 0) {
       return hipErrorNotReady;
@@ -101,11 +102,12 @@ hipError_t IPCEvent::synchronize() {
 
 // ================================================================================================
 hipError_t IPCEvent::streamWait(hip::Stream* stream, uint flags) {
-  int offset = ipc_evt_.ipc_shmem_->read_index;
+  const int offset = ipc_evt_.ipc_shmem_->read_index;
-  hipError_t status =
+  return ihipStreamOperation(
-      ihipStreamOperation(reinterpret_cast<hipStream_t>(stream), ROCCLR_COMMAND_STREAM_WAIT_VALUE,
+      reinterpret_cast<hipStream_t>(stream),
-                          &(ipc_evt_.ipc_shmem_->signal[offset]), 0, 1, 1, sizeof(uint32_t));
+      ROCCLR_COMMAND_STREAM_WAIT_VALUE,
-  return status;
+      &(ipc_evt_.ipc_shmem_->signal[offset]), 0, 1, 1,
+      sizeof(uint32_t));
 }
 
 // ================================================================================================
@@ -117,37 +119,41 @@ hipError_t IPCEvent::recordCommand(amd::Command*& command, amd::HostQueue* strea
 
 // ================================================================================================
 hipError_t IPCEvent::enqueueRecordCommand(hip::Stream* stream, amd::Command* command) {
-  amd::Event& tEvent = command->event();
   createIpcEventShmemIfNeeded();
-  int write_index = ipc_evt_.ipc_shmem_->write_index++;
+
-  int offset = write_index % IPC_SIGNALS_PER_EVENT;
+  // Allocate signal slot for this event
-  while (ipc_evt_.ipc_shmem_->signal[offset] != 0) {
+  auto* const shmem = ipc_evt_.ipc_shmem_;
+  const int write_index = shmem->write_index++;
+  const int offset = write_index % IPC_SIGNALS_PER_EVENT;
+  auto& signal = shmem->signal[offset];
+
+  // Wait for signal slot to become available
+  while (signal != 0) {
     amd::Os::sleep(1);
   }
-  // Lock signal.
+
-  ipc_evt_.ipc_shmem_->signal[offset] = 1;
+  // Lock signal and set device ID
-  ipc_evt_.ipc_shmem_->owners_device_id = deviceId();
+  signal = 1;
+  shmem->owners_device_id = deviceId();
   command->enqueue();
 
-  // Set event_ in order to release marked command when event is destroyed
+  // Set event_ to release marked command when event is destroyed
   if (event_ != nullptr) {
     event_->release();
   }
   event_ = &command->event();
 
-  // device writes 0 to signal after the hipEventRecord command is completed
+  // Device writes 0 to signal after hipEventRecord command completes
-  // the signal value is checked by WaitThenDecrementSignal cb
+  const auto status = ihipStreamOperation(reinterpret_cast<hipStream_t>(stream),
-  hipError_t status =
+                                          ROCCLR_COMMAND_STREAM_WRITE_VALUE, &signal, 0, 0, 0,
-      ihipStreamOperation(reinterpret_cast<hipStream_t>(stream), ROCCLR_COMMAND_STREAM_WRITE_VALUE,
+                                          sizeof(uint32_t));
-                          &(ipc_evt_.ipc_shmem_->signal[offset]), 0, 0, 0, sizeof(uint32_t));
-
   if (status != hipSuccess) {
     return status;
   }
 
-  // Update read index to indicate new signal.
+  // Update read index to indicate new signal
   int expected = write_index - 1;
-  while (!ipc_evt_.ipc_shmem_->read_index.compare_exchange_weak(expected, write_index)) {
+  while (!shmem->read_index.compare_exchange_weak(expected, write_index)) {
     amd::Os::sleep(1);
   }
 
@@ -169,23 +175,28 @@ hipError_t IPCEvent::GetHandle(ihipIpcEventHandle_t* handle) {
 // ================================================================================================
 hipError_t IPCEvent::OpenHandle(ihipIpcEventHandle_t* handle) {
   ipc_evt_.ipc_name_ = handle->shmem_name;
+
+  // Map shared memory from IPC handle
+  auto** shmem_ptr = reinterpret_cast<void**>(&ipc_evt_.ipc_shmem_);
   if (!amd::Os::MemoryMapFileTruncated(ipc_evt_.ipc_name_.c_str(),
-                                       (const void**)&(ipc_evt_.ipc_shmem_),
+                                       const_cast<const void**>(shmem_ptr),
                                        sizeof(ihipIpcEventShmem_t))) {
     return hipErrorInvalidValue;
   }
 
-  if (amd::Os::getProcessId() == ipc_evt_.ipc_shmem_->owners_process_id.load()) {
+  auto* const shmem = ipc_evt_.ipc_shmem_;
-    // If this is in the same process, return error.
+
+  // Prevent opening in the same process
+  const auto current_process_id = amd::Os::getProcessId();
+  if (current_process_id == shmem->owners_process_id.load()) {
     return hipErrorInvalidContext;
   }
 
-  ipc_evt_.ipc_shmem_->owners += 1;
+  shmem->owners += 1;
-  // device sets 0 to this ptr when the ipc event is completed
+
-  hipError_t status = hipSuccess;
+  // Register signal array with device
-  status =
+  constexpr size_t kSignalArraySize = sizeof(uint32_t) * IPC_SIGNALS_PER_EVENT;
-      ihipHostRegister(&ipc_evt_.ipc_shmem_->signal, sizeof(uint32_t) * IPC_SIGNALS_PER_EVENT, 0);
+  return ihipHostRegister(&shmem->signal, kSignalArraySize, 0);
-  return status;
 }
 
 // ================================================================================================
@@ -195,31 +206,33 @@ hipError_t hipIpcGetEventHandle(hipIpcEventHandle_t* handle, hipEvent_t event) {
   if (handle == nullptr || event == nullptr) {
     HIP_RETURN(hipErrorInvalidValue);
   }
-  hip::Event* e = reinterpret_cast<hip::Event*>(event);
+
+  auto e = reinterpret_cast<hip::Event*>(event);
   HIP_RETURN(e->GetHandle(reinterpret_cast<ihipIpcEventHandle_t*>(handle)));
 }
 
+// ================================================================================================
 hipError_t hipIpcOpenEventHandle(hipEvent_t* event, hipIpcEventHandle_t handle) {
   HIP_INIT_API(hipIpcOpenEventHandle, event, handle);
 
-  hipError_t status = hipSuccess;
   if (event == nullptr) {
     HIP_RETURN(hipErrorInvalidValue);
   }
 
-  status = ihipEventCreateWithFlags(event, hipEventDisableTiming | hipEventInterprocess);
+  // Create IPC event with timing disabled
+  constexpr uint32_t kIpcEventFlags = hipEventDisableTiming | hipEventInterprocess;
+  auto status = ihipEventCreateWithFlags(event, kIpcEventFlags);
   if (status != hipSuccess) {
     HIP_RETURN(status);
   }
 
-  hip::Event* e = reinterpret_cast<hip::Event*>(*event);
+  auto* const e = reinterpret_cast<hip::Event*>(*event);
-  ihipIpcEventHandle_t* iHandle = reinterpret_cast<ihipIpcEventHandle_t*>(&handle);
+  auto* const iHandle = reinterpret_cast<ihipIpcEventHandle_t*>(&handle);
 
-  status = e->OpenHandle(iHandle);
+  const auto open_status = e->OpenHandle(iHandle);
-  // Free the event in case of failure
+  if (open_status != hipSuccess) {
-  if (status != hipSuccess) {
     delete e;
   }
-  HIP_RETURN(status);
+  HIP_RETURN(open_status);
 }
 }  // namespace hip

projects/clr/hipamd/src/hip_module.cpp

@@ -509,7 +509,7 @@ hipError_t ihipModuleLaunchKernel(hipFunction_t f, amd::LaunchParams& launch_par
 
   if (stopEvent != nullptr) {
     hip::Event* eStop = reinterpret_cast<hip::Event*>(stopEvent);
-    if (eStop->flags_ & hipEventDisableSystemFence) {
+    if (eStop->flags() & hipEventDisableSystemFence) {
       command->setCommandEntryScope(amd::Device::kCacheStateIgnore);
     } else {
       command->setCommandEntryScope(amd::Device::kCacheStateSystem);