linux em tempo real
DESCRIPTION
Atualmente, o Linux vem sendo utilizado como sistema operacional de tempo real, tanto comercialmente quando academicamente. Esta apresentação introduz os conceitos básicos do Linux em tempo real, fazendo um paralelo com a teoria de sistemas de tempo real. Das implementações do kernel do Linux com características de tempo real, duas são apresentadas: o PREEMPT_RT, a alternativa comercial, e o LitmusRT, a alternativa acadêmica. Para cada implementação, são apresentados detalhes de sua implementação e exemplos de pesquisas que estão sendo desenvolvidas atualmente nestes sistemas.TRANSCRIPT
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Who I'm and what we will
talk about?
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What does Real-Time means?
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Event -> Response, latency,
response time,
deadline...
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Real-Time means
fast?
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Real Time != FAST!
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RT means
Determinism, WCET,
Response Time.
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How Red Hat shows your Real-Time Linux
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What is a Real-Time
Operating System?
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Real-Time Operating System Examples
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Why Linux is not a RTOS?
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Real-Time Linux: Past, Present, Possible
Futures...
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RTAI and Xenomai
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RT Task on Xenomai +
Non-RT on Linux... =
):) <- this is a bipolar emoticon
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PREEMPT-RT
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- latency+ control over OS tasks
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Preemptive lock
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Priority inversion problems...
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PREMPT-RT is WONDERFULL! Let's use everywhere!!!
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):)
This is another bipolar emoticon, but more happy than another...
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How expensive is PREEMP-RT?
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12 24 36 600
5
10
15
20
25
30
35
40
45
50
PREEMPT-RT
Vanilla
Concurrent channels
CP
U L
oa
d (
%)
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LITMUSRT
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A testbed for multiprocessor scheduling
in Real-Time Systems
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(Partitioned|Global|Clustered) EDF
Partitioned Fixed-Priority
PD2 (PFAIR)
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Mutual Exclusion
Interrupt Handling
Real-Time GPU Management
Tracing Tools
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What about SCHED_DEADLINE?
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Research Opportunities
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Questions?