Method Schedule

oneflow/core/vm/virtual_machine_engine.cpp:426–458

}

void VirtualMachineEngine::Schedule(const ScheduleCtx& schedule_ctx) {
  // Release finished instructions and try to schedule out instructions in DAG onto ready list.
  if (unlikely(mut_active_stream_list()->size())) { ReleaseFinishedInstructions(schedule_ctx); }
  // Try run the first barrier instruction.
  if (unlikely(mut_barrier_instruction_list()->size())) { TryRunBarrierInstruction(schedule_ctx); }
  // Handle pending instructions, and try schedule them to ready list.
  // Use thread_unsafe_size to avoid acquiring mutex lock.
  // The inconsistency between pending_instruction_list.list_head_.list_head_.container_ and
  // pending_instruction_list.list_head_.list_head_.size_ is not a fatal error because
  // VirtualMachineEngine::Schedule is always in a busy loop. All instructions will get handled
  // eventually.
  //  VirtualMachineEngine::Receive may be less effiencient if the thread safe version
  //  `pending_instruction_list().size()` used here, because VirtualMachineEngine::Schedule is more
  //  likely to get the mutex lock.
  if (unlikely(local_pending_instruction_list().size())) {
    HandleLocalPending();
  } else if (unlikely(pending_instruction_list().thread_unsafe_size())) {
    // MoveTo is under a lock.
    mut_pending_instruction_list()->MoveTo(mut_local_pending_instruction_list());
    if (local_pending_instruction_list().size()) { HandleLocalPending(); }
  }
  // dispatch ready instructions and try to schedule out instructions in DAG onto ready list.
  if (unlikely(mut_ready_instruction_list()->size())) {
    DispatchAndPrescheduleInstructions(schedule_ctx);
  }
  // handle scheduler probes
  if (unlikely(local_probe_list_.size())) {
    HandleLocalProbe();
  } else if (unlikely(probe_list_.thread_unsafe_size())) {
    probe_list_.MoveTo(&local_probe_list_);
    if (local_probe_list_.size()) { HandleLocalProbe(); }
  }
}

bool VirtualMachineEngine::SchedulerThreadUnsafeEmpty() const {
  return pending_instruction_list().thread_unsafe_size() == 0