A Component-Based QoS. Embedded Systems. Jean-Charles TournierFrance Télécom

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A Component-Based QoS Architecture for Embedded Systems Jean-Charles TournierFrance Télécom Jeancharles.tournier@rd.francetelecom.

1 A Component-Based QoS Architecture for Embedded Systems Jean-Charles TournierFrance Télécom Jean-Philippe Babau CITI / INSA Lyon ARTIST 2 - Component Modelling and Composition Paris, January 24th 2005 France Télécom R&D ARTIST2 01/24/2005

) lead to dedicated, closed and monolithic systems Tomorrow: need for flexible systems Dynamicity

2 Context - 1/2 Mobile embedded systems Today Complex features QoS constraints (real-time, safety, etc.) Limited resources (CPU, memory, battery, etc.) lead to dedicated, closed and monolithic systems Tomorrow: need for flexible systems Dynamicity Add or remove applications on the fly Opening Heterogeneous communication networks(gsm, GRPS, Bluetooth, etc.) France Télécom R&D ARTIST2-01/24/2005 2

3 Context - 2/2 Component Based Software Engineering (CBSE) An easier way to build complex software by assembling, composing software entities called components CBSE provides Adaptability Reusability Scalability Component frameworks (Think, OS-Kit, Coyote) Provide composition of components from a functional point of view But, no support for QoS management France Télécom R&D ARTIST2-01/24/2005 3

4 Objectives Dynamically manage QoS constraints in component-based systems Define a QoS architecture Open Independent of QoS management policies, Qos mechanisms and Qos specifications Component-based Supporting dynamic QoS management France Télécom R&D ARTIST2-01/24/2005 4

5 Overview Our view of components Main QoS concepts Qinna Experiment Analysis Conclusions France Télécom R&D ARTIST2-01/24/2005 5

6 CBSE - The Fractal Component Model Component Run-time entity Made of a content and a controller Content Composed of a finite number of other components (recursive) Under the control of the controller Controller Reflexivity E.g. Life-cycle, configuration, etc. Interface Unique access points Client or server Binding Oriented connection between two components From a client interface to a server interface (type compatibility) Primitive or composite (component+binding) France Télécom R&D ARTIST2-01/24/2005 6

7 CBSE - Fractal API Life-Cycle, Reflexivity (BindingController and ContentController), Instanciation (Factory) ADL A language for defining Fractal architectures (configuration) A modular and an open (extensible) language to describe Components, interfaces and bindings Attributes Typing Implementations Deployment Behaviour and QoS contracts France Télécom R&D ARTIST2-01/24/2005 7

8 CBSE - The Think Framework Think Framework for component-based operating systems Conforms to the Fractal model Everything is components Fine grain control over resources Two kinds of components Hardware Abstraction Components Boot, exceptions, MMU, device drivers (screen, keyboard, serial port, ), etc. OS Services Components Thread, scheduler (RR, priority, EDF, ), Network (Ethernet, IP, TCP, ), etc. Ported on ARM (Intel StrongARM, Intel xscale, Portal Player, Motorola Dragon Ball MX1), Intel x86, Hitachi H8 (Lego RCX) Provides a complete tools chain ADL and IDL parsers, component compiler, etc. France Télécom R&D ARTIST2-01/24/2005 8

9 Quality of Service architecture Concepts Specification Initialization Management Performance Importance Adaptation Mapping Admission Testing Reservation Observation Maintenance Adaptation GOOD HIGH GOOD AVERAGE BAD GOOD= 25 f/sec {6,10} EDF 80Kb Mem Sched_anal ({6,10})? set_prio ({6,10}) 25 f/sec? improve_ resssource() degrade_to AVERAGE France Télécom R&D ARTIST2-01/24/2005 9

10 Qinna A Component-Based QoS Architecture Capturing the main QoS concepts Generic Dynamic Reusable Qinna defines A set of APIs Component types Data types Inter-component relationships Dynamic behavior France Télécom R&D ARTIST2-01/24/

11 Qinna - QoSComponent Definition Provides functional interfaces with QoS management needs Detail Func_Itf (1..N) QoSComponent Local_Ct: T_CL Func_Itf (0..N) iqosobserver (1) ilocalconstraint (1) France Télécom R&D ARTIST2-01/24/

12 Qinna - QoSComponentBroker Definition Detail Provides a QoSComponent with a fixed local constraint Responsible for the admission testing and reservation for a class of QoSComponents ibrokeradministration (1) QoSComponentBroker Global_Ct: T_CG ilocalconstraint (0..N) iqosbroker (1) France Télécom R&D ARTIST2-01/24/

13 Qinna - QoSComponentManager Definition Initializes a QoSComponent from a QoS point of view Implements initialization, maintenance and adaptation mechanisms for a class of QoSComponents Detail QoSComponentManager imanageradministration Map_table: T_MT Contracts: T_CT_MANAGER (1) iqosbroker (1) iqosmanager (0..N) iqosmanager (1) iqosadapter (1) iqosmaintener (1) France Télécom R&D ARTIST2-01/24/

14 Qinna - QoSComponentObserver Definition Detail Implements observation policy for a class of QoSComponents iqosobserverlifecycle (1) QoSComponentObserver iqosobserverexception (1) iqosobserver (1..N) France Télécom R&D ARTIST2-01/24/

15 Qinna - QoSDomain Definition Encapsulates all Qinna components Implements adaptation and maintenance policies based on importance level Detail iqosdomain (1..N) QoSDomain Contracts: T_CT_DOMAIN iqosmaintener (0..N) iqosadapter (0..N) iqosmanager (1..N) iqosobserverexception iqosobserverlifecycle (0..N) (0..N) France Télécom R&D ARTIST2-01/24/

16 Qinna - Overview Functional services QoSComponent 1..N 1..N Admission testing Reservation Management mechanisms (initialization, adaptation, maintenance) Management policies (adaptation, maintenance) 1 QoSComponentBroker 1 1 QoSComponentManager 1..N 1 QoSDomain 0..N QoSComponentObserver 0..N Observation policy France Télécom R&D ARTIST2-01/24/

17 Experiment GUI DOOM Video Threads Memory EDF Video QoS Level Thread QoS Level Memory QoS Level (kb) Doom QoS Level Thread QoS Level Memory QoS Level (kb) GOOD {4,10} 60 GOOD {7,10} 50 AVERAGE {7,15} 30 BAD {4,20} 40 BAD {7,20} 20 France Télécom R&D ARTIST2-01/24/

18 Experiment - Qinna integration QoSDoom QoSThread QoSThread QoSEDF QoSVideo set( GOOD) QoSDoomBroker QoSThreadBroker QoSEDFBroker QoSVideoBroker Reserve( GOOD) QoSDoomManager Map(GOOD): Thread={7,10} Mem=50Kb DOOM=GOOD QoSThreadManager Reserve( {7,10}) Map({7,10}): Sched={7,10} Thread=given by QoSEDF QoSEDFManager Reserve({7,10}) Map({7,10}: Sched={7,10} QoSVideoManager Reserve(GOOD) QoSDomain Reserve( GOOD, LOW) GUI France Télécom R&D ARTIST2-01/24/

19 Analysis Dynamicity Allows dynamic QoS management Dynamic evaluation of QoS parameters Allows dynamic architecture reconfiguration Reusability Component-based Separation policy/mechanism Genericity Non QoS policy/mechanism/specification specific Each component has its own QoS mechanisms Management of heterogeneous QoS (real-time and non real-time) Real-time aspects Admission testing can be omitted (hard real-time) Performance depends on the implementation (avoid multiple admission testing) Adaptation occurs in soft real-time France Télécom R&D ARTIST2-01/24/

20 Conclusion Summary Qinna: component-based QoS architecture Some preliminary experiments including various QoS mechanisms, QoS policies and QoS specifications Benefits Dynamicity Reusability Genericity Future work Integrate complex QoS management policies Quantitative evaluation (LOC, memory, delay overhead, etc.) Supporting tools France Télécom R&D ARTIST2-01/24/

Real-Time & Embedded Operating Systems

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