Recommended
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Key considerations for multithreaded architectures in LabVIEW
Similar to Key considerations for multithreaded architectures in LabVIEW (20)
Recently uploaded
Recently uploaded (20)
Key considerations for multithreaded architectures in LabVIEW
- 1. Piotr Demski piotr.demski@sparkflow.pl Key Considerations for Multithreaded Architectures
- 2. What We Do? Custom Software Development Outsourcing Consulting Hardware Integration Sparkflow Sp z o.o. Kolejowa 57 40-602 Katowice Poland
- 3. We’re experts in NI Platform • PXI • cDAQ • cRIO, sbRIO • USRP • Machine Vision Systems Real-Time FPGA
- 4. Agenda The case Is single loop enough? Applications of multithreaded architecture Architecture design
- 5. Scope Applications that use multiple loops running in parallel
- 6. The Case • Create the application for the test stand. • 4 independent test slots. • Some test hardware is shared between slots. • Operator mounts the UUT in the slot and starts test. Operator then mounts another UUT in another slot. • Operator needs some control over the slot when mounting UUT. • Application needs to communicate with PLC and other equipment.
- 7. Is single loop enough for this application?
- 8. Simple State Machine • A single loop that combine user interface control and application logic. *File->Create Project->Simple State Machine
- 9. Simple State Machine • How do we handle multiple slots? • How do we handle user interaction during test? • How do we handle PLC and other equipment communication? *File->Create Project->Simple State Machine
- 10. (Some) Applications of multithreaded architectures Improving User Interface responsiveness Parallel processing
- 12. Improving User Interface responsiveness • 0.1 second is about the limit for having the user feel that the system is reacting instantaneously • 1.0 second is about the limit for the user's flow of thought to stay uninterrupted • 10 seconds is about the limit for keeping the user's attention *Jakob Nielsen, Usability Engineering (1993)
- 13. Queued Message Handler • Respond to user actions instantaneously in Event Handling Loop • Offload any processing to Message Handling Loop *File->Create Project->Queued Message Handler
- 14. Considerations • Make User Interface independent from the application logic.
- 15. Considerations • Make User Interface independent from the application logic. • Focus on proper messages design.
- 16. Considerations • Make User Interface independent from the application logic. • Focus on proper messages design. • Start project using existing architecture (QMH, Delacor QMH, your own code).
- 17. Considerations • Make User Interface independent from the application logic. • Focus on proper messages design. • Start project using existing architecture (QMH, Delacor QMH, your own code). • Consider splitting UI into multiple VIs.
- 19. How to make 4 independent slots? • Design a single Slot. • Use 4 instances of this Slot in application. • Design a single Test Stand that controls 4 Slots. • Use 1 instance of Test Stand in application.
- 20. Single Test Stand • Slots are processed sequentially. They should not do too much processing. • Any message to the Slot must be sent to the Test Stand with proper Slot ID.
- 21. Multiple Slot instances • Every slot is independent from another. They can do heavy processing internally without blocking each other. • Any message must be send to proper slot using this slot specific communication channel. • Slot VI and all subVIs must be reentrant (harder debugging).
- 22. Considerations • Select the right architecture for your application.
- 23. Considerations • Select the right architecture for your application. • Consider alternatives.
- 24. Considerations • Select the right architecture for your application. • Consider alternatives. • Identify blocking and time-consuming operations, move them to other threads.