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April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
1Philips Research
1st meeting of project EES.5653
Quality of Service for In-Home Digital Networks
PROGRESS PROJECT EES.5653
Terminal QoS
M.A. Weffers-Albu
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
2Philips Research
1st meeting of project EES.5653
Contents
• Project goals
• Approach
• Description of analyzed systems
• Trimedia Streaming Software Architecture
• A characterization of streaming applications execution
• DVD player case study
• Future work
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
3Philips Research
1st meeting of project EES.5653
QoS in IN-Home Digital Networks
Network
Aim: provide guaranteed and optimised Quality of Service (QoS) for interconnected real-time embedded systems.
Prediction
&
Optimisation
of
Performance Attributes:
AT, RT, NCS, RU.
Terminal QoS:
Reliability
&
Performance
Predictability of system.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
4Philips Research
1st meeting of project EES.5653
Component-based Real-Time Embedded Systems
…
… …
…
…
Physical Platform
Goals•Nearly optimised design for optimal resource utilization of the subsystems involved (good performance).
•Interference limited - reduced to a minimum through good design practices (good reliability).
•Fast integration of pre-designed subsystems.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
5Philips Research
1st meeting of project EES.5653
Component-based Real-Time Embedded Systems
…
… …
…
…
Physical Platform
Challenges
Scarcity of resources
Resource sharing
Low Predictability
Non-guaranteed Reliability & Performance
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
6Philips Research
1st meeting of project EES.5653
Component-based Real-Time Embedded Systems
…
… …
…
…
Physical Platform
Approach
Resource requirements
Resource reservations
Virtual Platforms
Guaranteed resource availability
while
Resource usage restricted to a
configured maximum.
VP1 VP2
VPn-1 VPn
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
7Philips Research
1st meeting of project EES.5653
Component-based Real-Time Embedded Systems
Approach
1. Derive the VPs of the subsystems involved by predicting performance quality parameters (NCS, AT, RT, RU) for each of the subsystems. (Specifications in terms of behaviour and performance).
2. Control performance quality parameters - find good practices of design for the subsystems so that their resources needs can be satisfied on the physical platform.
Example:
• Predict the number of context switches (NCS) – the overhead occurring during the execution of a system.
• Give guidelines for priority assignment such that the NCS is minimized.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
8Philips Research
1st meeting of project EES.5653
Component-based Real-Time Embedded Systems
Approach
3. Resources needs - strongly related to events that occur during the execution of a subsystem.
Repetitive patterns of events => Execution predictable
Identify the patterns of events during the execution of a subsystem…
· the conditions under which the events adopt repetitive patterns…
· the relations between the patterns of events.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
9Philips Research
1st meeting of project EES.5653
…
EQ EQ
FQ
EQ
FQC1
C2 Cn
FQ…
Empty Queue
Full Queue Full Queue
Empty Queue
Component
Processing code
Get Full Packet Put Full Packet
Put Empty Packet Get Empty Packet
Typical execution scenario of a TSSA component
- get 1 FP from input FQ,
- get 1 EP from input EQ,
- processing,
- put 1EP in output EQ.
- put 1FP in output FQ.
TriMedia Streaming Software Architecture
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
10Philips Research
1st meeting of project EES.5653
TriMedia Streaming Software Architecture TSSA components
Data driven. Execution determined by:
- Availability of necessary input
- Priority of component task
- Data driven with blocking due to communication with hardware. Execution determined by:
- Availability of necessary input
- Average blocking time
- Time driven. Execution determined by:
- Availability of necessary input. (Or NOT)
- Priority
- Periodicity.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
11Philips Research
1st meeting of project EES.5653
TriMedia Streaming Software Architecture TSSA components
All types. Execution determined by:
- Average computation time.
- n->m relation between input and output.
- If m variable – average m or distribution over time for the values of m.
- Average times needed to get each input FP/EP.
- Average times needed to produce each output FP/EP.
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
12Philips Research
1st meeting of project EES.5653
A characterization of streaming applications execution.
Theorem
Let C1, C2, C3, …, Cn be a chain of components communicating through a set of queues as in Figure 1. Provided that the components are designed such that their execution in the chain does not lead to deadlock, and provided that the input is sufficiently long, the execution of the components in the chain will adopt a repetitive pattern after a finite number of steps.
Hyperperiod
Initialization
Phase
Stable
Phase
Finalization
Phase
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
13Philips Research
1st meeting of project EES.5653
A characterization of streaming applications execution.
Definitions• Initialization phase – the interval of time until the execution of the components
reaches a repetitive pattern.
• Stable phase - the interval of time during which the all components execute according to a repetitive pattern.
• Hyperperiod – the interval of time needed for the execution of the repetitive pattern.
• Finalization phase – interval of time following the stable phase. The finalization phase starts when the first component does not have input anymore and finishes its execution. During the finalization phase the last transactions in the queues are completed and all the components are stopped
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
14Philips Research
1st meeting of project EES.5653
A characterization of streaming applications execution.
Chain:
- N data driven components
- n->m: 1->1
- priorities in descending order.
EQ EQ
FQ
EQ
FQ
C1C2 CN
FQ
P(C1) > P(C2) > …> P(CN)
…
C1C2 CN…
Initialization phase:C1: executes until output FQ is filled=> C1 - Blocked (b).
C2(p)C1(b), C2(p)C1(b), …, until C2(b) (FQ filled, EQ empty)C1(b),
C3(p)C2(p)C1(b) C2(b), C3(p) C2(p)C1(b) C2(b)… C3(p) C2(p)C1(b) C2(b), C3(b)
CN(p)CN-1(p)… C2(p)C1(b)C2(b)…CN-1(b),
Hyperperiod
Stable phase:CN(p)CN-1(p)… C2(p)C1(b)C2(b)…CN-1(b),
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
15Philips Research
1st meeting of project EES.5653
DVD player case study
FRead VDec SSE VO
EQEQ
FQ
EQ
FQFRead VDec SSE VO
FQ
P(FRead) > P(VDec) > P(SSE) > P(VO)
FRead
- Data driven with blocking
VO
-Time driven
- 1->2
VDec
-Data driven
-1->m, m variable
SSE
-Data driven
-1->1
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
16Philips Research
1st meeting of project EES.5653
DVD player case study
NCS_hyperperiod(FRead) = 5,
NCS_hyperperiod(VDec) = 9,
NCS_hyperperiod(SSE) = 8,
NCS_hyperperiod(VO) = 8.
the total NCS_hyperperiod = 5+9+8+8 =30;
In order to validate our results we measure the NCS on a duration of the stable phase equal with 30 hyperperiods.
NCS_StablePhaseMeasured = 895;
NCS_StablePhaseCalculated = 900;
April 18, 2023 Alina Albu, [email protected]
TU/e Computer Science, System Architecture and NetworkingPhilips Research Laboratories Eindhoven
17Philips Research
1st meeting of project EES.5653
Current & Future Work
Current Work• Proof “Stable State Theorem” in a general case of components
types combinations.• Provide design guidelines for optimizing the NCS, RU• Find patterns in the input stream that can be related to the
pattern of execution.
Future Work • Analyze patterns of memory access, bus utilization• Find relations between memory accesses, bus utilization and
the pattern of execution.• Provide ways for controlling the above patterns.• Consider multi-processor platforms.