t-kernel/itron - · pdf fileitron/t-kernel is chip-agnostic, ... andescore, arc 600, arm...

T-Kernel/ITRON

Ken Sakamura

Professor at the University of Tokyo

Chair of T-Engine Forum

1Copyright 2014 by T-Engine Forum., All Rights Reserved.

What is ITRON/T-Kernel?

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Embedded Systems

Computers are not just PCs Embedded systems

Software systems embedded inside consumer electronics,

automobiles, sensors/actuators, , etc.

In fact, 98% of computing devices are embedded systems

By 2020, over 40 billion embedded processors are predicted to be

sold annually [ARTEMIS Joint Undertaking (EU)]

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What is Real-Time?

(Hard) Real-Time Computer must process the given jobs within a specific amount

of time (referred to as deadline)

PCs are NOT hard real-time systems Users can wait until to disappear for practically indefinite

amount of time

Embedded systems ARE real-time systems E.g., Automobile must cause its brakes to work immediately

The time MUST be assured to be upper-bounded; otherwise,

Same for other embedded systems

Because embedded systems interact with physical environments

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Real-Time OS

Real-Time Operating System (RTOS) Operating system with real-time assurance

Multi-task (multi-thread) model

Simplifies programming of operation workflows

Task switching with real-time assurance

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Response time not bounded

Real-Time OS

Is RTOS really needed? Is it practical for application programmers to write application

codes to assume real-time behavior on multiple tasks by hand?

Apparently too complex to handle The use of event-driven OS is thus limited to extremely-

constrained devices & simple application scenarios

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Real-Time OSThen, why not Linux or Android?

Too heavy to ensure hard real-time, even when real-time

scheduler is selected

Lets compare the boot sequence

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Linux (typically boots with 10 secs) T-Kernel 2.0 + T2EX (boots instantly)

TRON Project

TRON Project Started in 1984 to build an ideal computer architecture

The vision we pursue has been HFDS (highly functional

distributed system)

a.k.a. IoT (Internet of Things), Ubiquitous Computing, M2M,

One of the most important contributions is the

standard embedded real-time OS (RTOS)

ITRON (Industrial TRON) family (1987)

T-Kernel family (2002)

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ITRON

ITRON Features Real-time operating system

TRON sub-framework for embedded devices

Open architecture

Specification made publicly available without any fee

Chip Agnostic

Not restricted to a specific hardware nor chip

Efficient

Equipped with abundant synchronization/communication API

No virtualization, no processes

Optimization

Allows chip-dependent optimizations

Relaxed specifications of chip-dependant functions (like interrupts)

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The Birth of T-Kernel

Evolution of OS never ends As long as the computer evolves

e.g. 64-bit address space space-efficient page tables

e.g. higher clock frequency low-power (clock/power-gating, etc.)

e.g. multi-core, virtualization

Embedded technology advanced a lot since ITRON in 1987

T-Kernel is the ITRON for the 21st century Based on the ITRON, industrial-proven for long since 1980s

But with major revision to be adopted for computing technology

of the 21st century

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T-Kernel

Additional T-Kernel Features Open source

The source code for T-Kernel is distributed for free

Anyone can use it, alter them, and sell them

Higher compatibility

Achieved by the reference source code

The original source code defines the specification, with no

ambiguity

Middleware and applications made reusable

High compatibility makes software no longer strongly tied to

specific board or chip

Minimize the cost to develop richer embedded application systems

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Acceptance of ITRON/T-Kernel

ITRON/T-Kernel as a de facto standard Due to the successful concept and cooperation, ITRON/T-

Kernel is now one of the de facto standards in the world RTOS

According to a survey, ITRON/T-Kernel has had the topmost

share for 18 consecutive years

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TRON Ecosystem

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Maturity of ITRON/T-Kernel

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Maturity

ITRON/T-Kernel is a mature technology, having

almost 30 years of industrial experience

Thus accepted by mission critical applications Artificial satellites, spacecrafts,

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Space Ships

Hayabusa Launched in May 2013, and returned to the Earth in June 2010

Has continued to work for 7 years in space

Space Ship Hayabusa CPU: SH-3(SH7708) with triple redundancy

OS: ITRON

Space Probe MINERVA CPU: SH-3 (SH7708)

OS: ITRON

Copyright 2014 by T-Engine Forum., All Rights Reserved.

Artificial Satellites

Space Ship Akatsuki and Solar Power Sail IKAROS Launched in May 2010

Controlled by T-Kernel Camera control for Venus

atmosphere observation

Expansion and control of solar sail

Processing photographs

Space Telescope Hisaki (SPRINT-A) Launched in September 2013

Controlled by T-Kernel

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Proven Performance

T-Kernel performance proved to perform the best

in IEEE-authorized, third-party paper In both context-switching and interrupt-handling

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Source: T.Nguyen, B. Anh, S. Tan: Real-time operating systems for small microcontrollers,

IEEE Micro Sept./Oct. 2009, pp-30-45

Evolution of ITRON/T-Kernel

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Evolving T-KernelAgain, evolution of OS never ends

As long as the computer evolves

T-Kernel has continued to evolve to meet the

demands of the era T-Kernel Standard Extension

T-Kernel

MP T-Kernel (SMP/AMP)

T-Kernel 2.0

T-Kernel 2.0 Extension (T2EX)

T-Kernel 2.0

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Evolving T-Kernel

T-Kernel Standard Extension Extension to add PC-like rich OS functionalities to RTOS

File systems, processes, standard I/O,

Accepted in informational devices

Car navigation systems,

T-Kernel Compacted version of T-Kernel

Can be used with 8KB ROM and 4KB RAM

Suitable for 16-bit/32-bit processors with less ROM/RAM

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Evolving T-Kernel

MP T-Kernel Multi-processor and Multi-core support for T-Kernel

Support for two models: AMP and SMP

AMP (Asymmetric multi-processing)

Each OS instance for each processors/cores Suitable for I/O-intensive applications,

especially when tasks works with little dependencies

SMP (Symmetric multi-processing)

One OS instance works on multi-processors No need to define which task on which CPU Suitable for CPU-intensive applications Tend to lose real-time behavior by locks for resource protection

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Evolving T-Kernel

T1 to T2 After 10 years of T-Kernel, embedded computer systems have

drastically changed

At the same time, network, communication, and server-side

technologies have evolved

e.g., IPv6, WPAN, Cloud Computing,

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Now is the time for major update of T-Kernel:

T-Kernel 2.0 (T2) the new RTOS for the age of IoT(Internet of Things)

Evolving T-Kernel 2.0

T-Kernel 2.0 Major update of T-Kernel for the next decades

Real-time support beyond RTOS

Microsecond API (e.g., tk_dly_tsk_u)

Physical-timer functions

Fast locks (FastLock, FastMLock, )

Microwaits (WaitUsec, WaitNsec, )

Support for large-capacity devices

Embedded systems now handles large-capacity disks

e.g. Digital camera with MicroSD card > 4GB

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Evolving T-Kernel 2.0

Is Microsecond API really needed? Not always, but YES

e.g. engines and motors

When they rotate with 6,000 times per minute (6,000rpm), they

rotate 36 degrees in 1 millisecond

e.g. network communications

Inter-frame gap of Ethernet (10Mbps): 9.6s

Initial retransmit time of data-link layer protocols

(incresed by exponential backoff): 10s200s

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Evolving T-Kernel

T-Kernel 2.0 Extension (T2EX) RTOS Extension w