X-Lap : A Systems Approach for Cross-Layer Profjling and Latency - PowerPoint PPT Presentation

X-Lap : A Systems Approach for Cross-Layer Profjling and Latency Analysis for Cyber-Physical Networks RTN 2017 Stefan Reif, Timo Hönig, Wolfgang Schröder-Preikschat Department of Computer Science 4 (Distributed Systems and Operating Systems) Friedrich-Alexander-Universität Erlangen-Nürnberg Andreas Schmidt, Thorsten Herfet Telecommunications Lab Saarland Informatics Campus - Saarbrücken June 27, 2017

Cyber-Physical Networks (CPNs) 2 / 19

Cyber-Physical Networks (CPNs) 2 / 19

Cyber-Physical Networks (CPNs) 2 / 19

Cyber-Physical Networks (CPNs) 2 / 19

Existing Solutions Single-Host Evaluation Tools Network Evaluation Tools Need for Cross-Layer-Analysis of communication stacks 3 / 19 ▶ Network protocol evaluation ▶ Local evaluation ▶ Abstract from host-related delays ▶ Network-oblivious

Existing Solutions Single-Host Evaluation Tools Network Evaluation Tools Need for Cross-Layer-Analysis of communication stacks 3 / 19 ▶ Network protocol evaluation ▶ Local evaluation ▶ Abstract from host-related delays ▶ Network-oblivious

Outline Introduction X-Lap PRRT Evaluation Conclusion 4 / 19

Outline Introduction X-Lap PRRT Evaluation Conclusion 4 / 19

X-Lap | Introduction X-Lap Application Transport protocol Operating system Channel Packet creation Error correction ... Inter-process communication (IPC) Resource management ... Transmission delay Propagation delay ... 5 / 19

X-Lap | Introduction X-Lap Application Transport protocol Operating system Channel 5 / 19 ▶ Packet creation ▶ Error correction ▶ ... ▶ Inter-process communication (IPC) ▶ Resource management ▶ ... ▶ Transmission delay ▶ Propagation delay ▶ ...

X-Lap | Architecture Minimize run-time Correlation analysis Outlier analysis Jitter amongst packets Single-packet traces Combine trace data Collect traces source code Embedded into protocol interference Trace every packet jk *.csv Ofg-line analysisjk Run-time evaluationjk 6 / 19 ▶ Timestamping functions ▶ Data analysis ▶ ⇒ Timestamps ▶ ⇒ Latency and jitter ▶ C codejk ▶ Python code

X-Lap | Architecture jk Correlation analysis Outlier analysis Jitter amongst packets Single-packet traces Combine trace data Collect traces source code interference 6 / 19 Ofg-line analysisjk *.csv Run-time evaluationjk ▶ Timestamping functions ▶ Data analysis ▶ ⇒ Timestamps ▶ ⇒ Latency and jitter ▶ C codejk ▶ Python code ▶ Trace every packet ▶ Minimize run-time ▶ Embedded into protocol

X-Lap | Architecture jk Correlation analysis Outlier analysis Jitter amongst packets Single-packet traces source code Embedded into protocol interference Minimize run-time Trace every packet *.csv Ofg-line analysisjk Run-time evaluationjk 6 / 19 ▶ Timestamping functions ▶ Data analysis ▶ ⇒ Timestamps ▶ ⇒ Latency and jitter ▶ C codejk ▶ Python code ▶ Collect traces ▶ Combine trace data

X-Lap | Architecture *.csv Combine trace data Collect traces source code Embedded into protocol interference Minimize run-time jk Trace every packet Ofg-line analysisjk Run-time evaluationjk 6 / 19 ▶ Timestamping functions ▶ Data analysis ▶ ⇒ Timestamps ▶ ⇒ Latency and jitter ▶ C codejk ▶ Python code ▶ Single-packet traces ▶ Jitter amongst packets ▶ Outlier analysis ▶ Correlation analysis

Outline Introduction X-Lap PRRT Evaluation Conclusion 7 / 19

Predictably Reliable Real-time Transport (PRRT) UDP TCP Not suitable for reliable real-time networks PRRT Error correction Latency-awareness 8 / 19 ▶ Data integrity checks ▶ No timeliness guarantees ▶ Error control ▶ No timeliness guarantees

Predictably Reliable Real-time Transport (PRRT) UDP TCP Not suitable for reliable real-time networks PRRT Error correction Latency-awareness 8 / 19 ▶ Data integrity checks ▶ No timeliness guarantees ▶ Error control ▶ No timeliness guarantees �

Predictably Reliable Real-time Transport (PRRT) UDP TCP Not suitable for reliable real-time networks PRRT 8 / 19 ▶ Data integrity checks ▶ No timeliness guarantees ▶ Error correction ▶ Latency-awareness ▶ Error control ▶ No timeliness guarantees �

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Error Control and Timeliness Automated Repeat reQuest (ARQ) Forward Error Correction (FEC) Hybrid Error Correction (HEC) Adaptive HEC (AHEC) + Application Constraints Channel State Information (CSI) Run-time CSI System Information Jitter 9 / 19

PRRT | Interaction with X-Lap Benefjts from X-Lap Goals: Latency and jitter ... 10 / 19 ▶ Obtain system information ▶ Analyse jitter ▶ ... avoidance → Eliminate causes of latency and jitter ▶ ... hiding → Preparatory/Clean-up tasks → Optimise resource management ▶ ... tolerance → Parameters for AHEC

Outline Introduction X-Lap PRRT Evaluation Conclusion 11 / 19

X-Lap | Evaluation scope X-Lap Application Transport protocol Operating system Channel Evaluation focus Future work 12 / 19 ▶ PRRT ▶ Interaction with OS ▶ Application delays ▶ Network transmission time

PRRT | Results: Packet Trace 13 / 19 Feedback ReceiverIPC HandlePacket ReceiverTotal LinkTransmit PrrtTransmit SenderEnqueued Enqueue SenderIPC Submit Send SenderTotal EndToEnd 0 20 40 60 80 Time [us]

PRRT | Results: Trace Jitter 14 / 19 Feedback ReceiverIPC HandlePacket ReceiverTotal LinkTransmit PrrtTransmit SenderEnqueued Enqueue SenderIPC Submit Send SenderTotal EndToEnd 0 20 40 60 80 100 Time [us]

PRRT | Results: Outliers 15 / 19 40 30 Frequency 20 10 0 C t d t C t k g e d t e e i i c n u n i P k m P m m u a i e e I c I d r e s r s b u S b a n n o e u e d q u P a a c v q d e n S i e r r e e n T n T e E l D c d E e F t k e n S r r n R a e r P i H d L n e S

16 / 19 PRRT | Results: Correlation SenderTotal 140 120 100 EndToEnd [us] 80 60 40 20 40 60 80 100 SenderTotal [us]

17 / 19 PRRT | Results: Correlation ReceiverIPC 140 120 100 EndToEnd [us] 80 60 40 5 10 15 20 25 ReceiverIPC [us]

Outline Introduction X-Lap PRRT Evaluation Conclusion 18 / 19

Conclusion X-Lap Thank you for your attention. Questions? LinkTransmit ReceiverIPC SenderEnqueue Jitter LinkTransmit SendFeedback PrrtTransmit Latency Network-related Receiver Sender PRRT Analysis 19 / 19 → http://xlap.larn.systems Source Code available at: ▶ Cross-layer, inter-host timing analysis tool ▶ Evaluation of real-time network protocols

Conclusion X-Lap Thank you for your attention. Questions? LinkTransmit ReceiverIPC SenderEnqueue Jitter LinkTransmit SendFeedback PrrtTransmit Latency Network-related Receiver Sender PRRT Analysis 19 / 19 → http://xlap.larn.systems Source Code available at: ▶ Cross-layer, inter-host timing analysis tool ▶ Evaluation of real-time network protocols