Integration of Generic Operating Systems in Partitioned Architectures (presentation)
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Transcript of Integration of Generic Operating Systems in Partitioned Architectures (presentation)
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Integration of Generic
Operating Systems in
Partitioned Architectures
João Pedro Gonçalves Crespo Craveiro
Supervisor: Prof. José Rufino
Provas públicas do
Mestrado em Engenharia Informática22 September 2009, Lisbon, Portugal
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Outline
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
2
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
3
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
ARINC 653 specification
• Important part of IMA– Partition environment
– Multiple functions, of
different criticality levels
– Shared computing platform
• Standard interface
between application
software and
operating system
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Partition management, process management, time management,
inter- and intrapartition communication, health monitoring
Optional services (ARINC 653 Part 2)
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Temporal and spatial
segregation
• Temporal segregation– Activities in one partition do not interfere with the
remaining partitions
– Fixed cyclic scheduling of partitions
• Spatial segregation– Applications in one partition cannot access memory
zones outside that partition
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
6
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
IMA/ARINC 653 in space
• Space industry players, ESA:– Identified similarities between the requirements of
space and aeronautical apps
– Established requirements for the employment of the
IMA concepts in space
– No major technological feasibility impairments identified
• Following the interest of ESA:– Proof of concept
– Demonstration of feasibility
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AIRARINC 653 In
Space RTOS
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR system architecture
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• Time and space partitioning
• Two-level hierarchical scheduling
• Hardware and OS independence
• Different OSs among partitions
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR system architecture
AIR PMK
• Fixed cyclic partition scheduling (first level)– Second level (process): native partition OS process
scheduler
• Partition dispatching– Notify heir partition of clock ticks elapsed while it was
inactive
– Partition context save and restore
• Mode-based schedules (NEW)
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR system architecture
APEX and AIR HM
• Flexible Portable APEX– Services defined in ARINC 653
– Generic OSs: only subset of the APEX services
• Management/monitoring, interpartition communication
• AIR Health Monitoring (HM)– Responsible for handling HW/SW errors
– Isolate errors within domain of occurence
• Process
• Partition
• System
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Time and space partitioning
Time partitioning
• Two-level hierarchical
scheduling
• Fixed cyclic partition
scheduling, RTOS
process scheduling
Space partitioning
• High-level processor-
independent abstraction
• Mapping of high-level
partition description to
low-level mechanisms
11
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
12
1-13
João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR POS Adaptation Layer
13
• Evolved from a paravirtualization layer below the POS
• Identified requirement for integration of generic OSs
• Confirmed observation that partitions hosting RTOSs
would also benefit from its presence
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR POS Adaptation Layer
Flexible POS integration
• POS-independent PMK1. POS initialization procedures
2. Interface with AIR PMK
components (e.g. partition
scheduler/dispatcher)
• APEX3. Map sys calls onto POS or
AIR-specific services
• HM4. Triggered by raising
exception
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
AIR POS Adaptation Layer
Development process
• Separation of
concerns
• Reusable building
blocks
• Less time spent on
interactions
• Modifications
restricted, better
validation efforts
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Enhanced timeliness mechanisms
Mode-based schedules
• Adaptation to different
modes/phases of
operation
• Accomomodation of
component failure
• Schedule change only
becomes effective at
the end of the MTF
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Enhanced timeliness mechanisms
Process deadline monitoring
• Process may miss
deadline when
partition inactive– Operational fault
– Uncertain WCET, partition
windows underdimensioned
• Only earliest
deadlines verified,
right after clock tick
update
17
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Demo
18
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
19
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Integration of generic
operating systems
• Motivation:– Application portability
• Interpreted / scripting languages
– Hardware interface / device driver availability
• Case study – (Embedded) Linux:– Open source
– Portable (processor architectures, HW configurations)
– Modular and configurable
– Soft real-time developments
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Embedded Linux
21
• Approach:
– Configuration of a vanilla Linux kernel
• Portability/maintainability
– Smaller system library (uClibc)
• Optimized /trimmed implementations
– Provision of standard commands more efficiently (BusyBox)
• Optimized/trimmed implementations
• Single executable file
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Embedded Linux
Overall results
• Linux kernel 2.6
• uClibc
• Busybox (system
tools)
Entire Linux OS fitting
in less than 2 MiB
22
Will coexist with other POSs and reside always in memory
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Integration of Linux in AIR
Paravirtualization in Linux
• Temporal partitioning
ensurance inherent– But Linux can still
undermine it
• Paravirtualization– Not all ISAs fully
virtualizable
• VMI / paravirt-ops– Allows same kernel to run
either natively or as
paravirtualized guest
23
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Integration of Linux in AIR
Linux partition and AIR PAL
• In AIR, AIR PAL will
provide the VMI layer
to the POS
• Interactions with the
AIR PMK when
required
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
• Aerospace applications: concepts
• AIR: ARINC 653 In Space RTOS
• Improving the AIR Technology
– AIR POS Adaptation Layer
– Enhanced timeliness mechanisms
• Integration of generic operating systems
– Case study: (Embedded) Linux
• Concluding remarks and future work
25
1-26
João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Concluding remarks (I)
• New component, AIR PAL, allowing:– stable POS-independent AIR PMK
– homogenous POS integration;
– better development process workflow
• Advanced timeliness adaptation and
monitoring mechanisms– absent in other ARINC 653/TSP solutions, both
opensource(XtratuM)andcommercial(WindRiver’s
VxWorks 653)
26
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Concluding remarks (II)
• Study of Linux as a generic non-RT POS in
AIR– Embedded approach yields encouraging results, given
the POS coexistence in memory
– Proposal of paravirtualization mechanisms to
guarantee Linux does not compromise TSP-related
safety
– Implementation of AIR prototype complete with a
Linux partition was deemed incompatible with the
duration of the project
27
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João Craveiro, LaSIGE/FCUL, Portugal <[email protected]>
Provas públicas do Mestrado em Engenharia Informática
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Future work
• Direct follow-ups– Prototype implementation (IA-32, SPARC)
– Extend to other generic POSs, like Windows (WRK)
• Consolidate/extend TSP support– Integrate interactions with environment, via
sensors/actuators
• TSP scheduling and multicore– Working plan approved for funding through an
Individual Doctoral Grant from FCT
28
Copyright © 2008-2009 Navigators - LASIGE – FCUL
Questions?
João Craveiro
LaSIGE/FCUL, Lisboa, Portugal
Homepage: http://lasige.di.fc.ul.pt/~jcraveiro/
E-mail: [email protected]
More information:
• AIR projects website, at http://air.di.fc.ul.pt• J. Craveiro, J. Rufino, C. Almeida, R. Covelo, and P.Venda,“Embedded Linux in a partitioned
architecture for aerospace applications,”inProc. 7th ACS/IEEE Int’l Conf. on Computer
Systems and Applications, Rabat, Morocco, May 2009.
• J. Rufino, J. Craveiro, T. Schoofs, C. Tatibana,andJ.Windsor,“AIR Technology: a step towards
ARINC 653 in space,”inDASIA 2009 "DAta Systems In Aerospace" Conference, Istanbul, Turkey,
May 2009.
• J. Craveiro, J. Rufino, T. Schoofs,andJ.Windsor,“Flexible Operating System Integration in
Partitioned Aerospace Systems,”inINForum 2009 – Simpósio de Informática, Lisbon, Portugal,
Sep. 2009. (Nominated for Best Student Paper award)