João Américo and Walter Rudametkin
Bull S.A.S./LIG Grenoble
Predictability vs. Dynamism:
managing dynamic real-time
applic...
Outline
• Context
• State-of-the-art
• Problem Identification
• Suggested Approach
• Limitations
• Conclusions and perspec...
About
• Walter RUDAMETKIN
– PhD student at Université de Grenoble
• João AMÉRICO
– PhD student at Université de Grenoble
–...
Context
Dynamic
Adaptive
Applications
Real-time
Applications
?Architecture evolution
Software maintenance
Deterministic ex...
State-of-the-art
RTSJ: Real-time Specification for Java
• Issues: garbage collection, dynamic class
loading, thread schedu...
State-of-the-art
Real-time OSGi
• Works focused mainly on isolation issues:
ARFLEX Project, [Richardson, 2009],
AONIX’s Re...
Problem Identification
• OSGi platform is inappropriate for
real-time applications
– Memory issues
– Scheduling issues
– I...
Simple Use Case
Update/Reconfiguration
Security
Camera
TFrame = 4 ms
Security
Camera
TFrame = 5ms
Motion Detection
System
...
Suggested Approach
• Distinction between critical and non-critical
code
– Architecture freezing policy
– Dynamic Real-time...
Architecture Freezing
• Application = set of states
– Each state corresponds to an architecture
(service bindings)
State S...
Architecture Freezing
• Real-time processing states
– Architecture modifications forbidden
State S2 State S3
Add
Remove
Ad...
Service Level Agreement
Service Registry
Contract
Monitor
SLA
Needs
!
Notation
Required Service
Provided Service
September...
Real-Time Dynamic SLA
• Extension to the D-SLA model [Touseau, 2010]
– Task type
– Period
– Worst case execution time (WCE...
Implementation
• iPOJO component model extension
September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managin...
Validation
 Architectures frozen during
real-time processing states
 SLM not implemented
September 2010 AMÉRICO, RUDAMET...
Limitations
• One real-time application at a time
• Unknown update times
• Component characterization
– Resource utilizati...
Results
• Architectural Freezing solves:
– Dynamic update
– Service interruptions
•but not disappearance of physical devic...
THANK YOU FOR YOUR
ATTENTION!
Contact: {Joao.Americo, Walter.Rudametkin}@imag.fr
September 2010 AMÉRICO, RUDAMETKIN – Pred...
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OSGi Community Event 2010 - Predictability vs Dynamism - Managing dynamic real-time applications

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OSGi Community Event 2010 - Predictability vs Dynamism - Managing dynamic real-time applications (Walter Rudametkin - Bull S.A.S.)

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OSGi Community Event 2010 - Predictability vs Dynamism - Managing dynamic real-time applications

  1. 1. João Américo and Walter Rudametkin Bull S.A.S./LIG Grenoble Predictability vs. Dynamism: managing dynamic real-time applications
  2. 2. Outline • Context • State-of-the-art • Problem Identification • Suggested Approach • Limitations • Conclusions and perspectives September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 2/18
  3. 3. About • Walter RUDAMETKIN – PhD student at Université de Grenoble • João AMÉRICO – PhD student at Université de Grenoble – BSc at UFRGS (2010), MSc at Université Joseph Fourier (2010), Engineer Degree at ENSIMAG (2009) September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 3/18
  4. 4. Context Dynamic Adaptive Applications Real-time Applications ?Architecture evolution Software maintenance Deterministic execution Low jitter September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 4/18
  5. 5. State-of-the-art RTSJ: Real-time Specification for Java • Issues: garbage collection, dynamic class loading, thread scheduling, etc. Dynamic Evolution/Adaptation • Architecture modification at runtime Real-time dynamic adaptive software • Based on QoS objects (QoSkets), modes (SOFA-HI/Blue-ArX), and real-time adaptations for CCM (CIAO, Cardamom). September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 5/18
  6. 6. State-of-the-art Real-time OSGi • Works focused mainly on isolation issues: ARFLEX Project, [Richardson, 2009], AONIX’s Real-time OSGi model • Industry initiatives: Oracle/BEA’s WebLogic Real-time, Integration between Perc and mBS September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 6/18
  7. 7. Problem Identification • OSGi platform is inappropriate for real-time applications – Memory issues – Scheduling issues – Isolation issues – Runtime software evolution September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 7/18
  8. 8. Simple Use Case Update/Reconfiguration Security Camera TFrame = 4 ms Security Camera TFrame = 5ms Motion Detection System Real-time ∑TFrame ≤ 10ms Security Camera TFrame = 3ms Security Camera TFrame = 6ms Display Application Non real-time Notation Required Service Provided Service getFrame() getFrame() getFrame() September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 8/18
  9. 9. Suggested Approach • Distinction between critical and non-critical code – Architecture freezing policy – Dynamic Real-time SLA September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 9/18
  10. 10. Architecture Freezing • Application = set of states – Each state corresponds to an architecture (service bindings) State S2 State S3 Add Remove State S1 Update Update Update Add Remove September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 10/18
  11. 11. Architecture Freezing • Real-time processing states – Architecture modifications forbidden State S2 State S3 Add Remove Add Remove State S1 Update Update Update State RTS1 State RTS2 State RTS3 Enter RT state Leave RT state Enter RT state Leave RT state Enter RT state Leave RT state September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 11/18
  12. 12. Service Level Agreement Service Registry Contract Monitor SLA Needs ! Notation Required Service Provided Service September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 12/18
  13. 13. Real-Time Dynamic SLA • Extension to the D-SLA model [Touseau, 2010] – Task type – Period – Worst case execution time (WCET) – Resource Utilization – Priority September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 13/18
  14. 14. Implementation • iPOJO component model extension September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 14/18
  15. 15. Validation  Architectures frozen during real-time processing states  SLM not implemented September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 15/18
  16. 16. Limitations • One real-time application at a time • Unknown update times • Component characterization – Resource utilization measures • Overhead September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 16/18
  17. 17. Results • Architectural Freezing solves: – Dynamic update – Service interruptions •but not disappearance of physical devices • Dynamic RT-SLA solves: – Service admission •based on resource consumption, deadlines, … • Both require modifying apps (explicit notifications) September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 17/18
  18. 18. THANK YOU FOR YOUR ATTENTION! Contact: {Joao.Americo, Walter.Rudametkin}@imag.fr September 2010 AMÉRICO, RUDAMETKIN – Predictability vs. Dynamism: Managing dynamic real-time applications 18/18

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