RTOS on hardware

오후 4:39 2008-02-25
조경민 bro@shinbiro.com
RTOS on hardware
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OS의 일부 기능을 hardware로 구현하여 overhead를 줄이는 분야
특히 OS의 scheduler나, synchronizer를 하드웨어로 만드는게 주류

개괄 설명 강추 자료
6th RTL Workshop: RTOS Acceleration techniques -- Review and Challenges
http://www.linuxdevices.com/articles/AT8022215906.html
Co-processor apporach
- task scheduling co-processor
- onchip programmable I/O processor
RTOS Primitives in Hardware
- F-Timer
- Spring Scheduling Co-processor
Hardware RTOS
- FASTCHART
- FASTHARD
- Silicon TRON
Instruction Set Customization
- task switch같은 OS기능 custom 명령을 추가하여 하드웨어에서 처리

Multitasking operations require more hardware based RTOSes
By Tommy Klevin, Product Manager, RealFast AB, Vasteras, Sweden, EE Times
February 24, 2003 (10:36 a.m. EST)
Embedded OS도 요즘 multitasking을 많이하는데, sw기반 os에서는 clock tick인터럽트를 이용하여 task switch를 한다. 그러나 clock tick을 쓰지 않고 직접 task switch interrupt를 구현하자.이렇게 함으로써 20% cpu time을 app에서 더 쓰게 할 수 있다.
다른 장점으로 clock tick을 sw task switch에 쓰지 않기 때문에 hw kernel은 sw커널보다 clock tick 단위를 1ms이하로 핸들할 수 있게 된다.
http://www.us.design-reuse.com/articles/5003/multitasking-operations-req
uire-more-hardware-based-rtoses.html

Sierra RTOS
스웨덴 realfast사(realfast.se)에서 2005년에 개발
이 후 prevas사에서 판매
http://www.prevas.com/productdevelopment/products/prevassierra.4.7ebfd4a210f9150c2bd80002274.html


Lennart Lindh, From Single to Multiprocessor Real-Time Kernels in Hardware,  1995 IEEE
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spring project
real time kernel을 hardware coprocessor로 놓은 것(1991)

RTU (real time unit으로 scheduler, semaphore등 일부 기능만 하드웨어로 만듬)
FASTCHART (1992), FASTHARD (1993), RTU94 (1994, 이기종 멀티프로세서향)

PERFORMANCE and DETERMINISM
- deterministic multitasking and multiprocessor real time kernel,
- the speed with which real time service calls are executed is increased by several orders of magnitude compared with a conventional CPU-based solution.
- no clock tick interrupt to the CPU is needed.

PORTABILITY
-no memory requirements,
-no special instruction format,
-no special CPU, only one interrupt and an external data bus (FASTHARD and RTU94).

SOFTWARE DESIGN
- simpler software system since the program code for the real time kernel does not occupy CPU memory,
- simpler timing analysis of the system,
- improved understandability when the system is divided into parts (complexity reduction),
- all RTK service calls are isolated in the RTU (no problem with interference between different service call
- no external interrupt handler in the software,
- simplified debugging of the software tasks, since different protection modes are not required,

Scheduler in FPGA
http://wiki.ittc.ku.edu/hybridthread/Image:RTSS_FPGA_Scheduler.pdf

Paper Reference
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대부분이 IEEE에서 찾은 것으로 파일명이 제목이니 구글 검색해보면 논문을 볼 수 있다.
1991_00144077_Fastchart-a fast time deterministic CPU and hardware based real-time-kernel.pdf
1991_00139929_FASTCHART-idea and implementation [virtual machine].pdf
1992_00637466_FASTHARD - A Fast Time Deterministic HARDware Based Real-time Kernel.pdf
1993_00393392_The spring scheduling co-processor- a scheduling accelerator.pdf
1993_00393510_The Spring scheduling co-processor- Design, use, and performance.pdf
1993_00639104_FASTCHART - Performance, Benefits and Disadvantages of the Architecture.pdf
1995_00516193_From single to multiprocessor real-time kernels in hardware.pdf
1996_00557849_Real-time kernel in hardware RTU- a step towards deterministic and high-performance real-time systems.pdf
1999_00748199_The spring scheduling coprocessor- a scheduling accelerator.pdf
2002_GIT-CC-02-19_A New Multiprocessor RTOS Kernel for. System-on-a-Chip Applications.pdf
2003_01195108_A comparison of the RTU hardware RTOS with a hardwaresoftware RTOS.pdf
2004_KrishnamoorthyBaskaran-HWOS.pdf
2005_01547468_Application specific real-time microkernel in hardware.pdf
aspdac_2003ppt_A Comparison of the RTU Hardware RTOS with a HardwareSoftware RTOS.pdf
2005_01568513_Reconfigurable hardware operating systems.pdf
2005_01612697_hthreads- a hardware_software co-designed multithreaded RTOS kernel.pdf
2005_RTSS_FPGA_Scheduler_FPGA Implementation of a Priority Scheduler Module.pdf
2007_04289055_A Real-Time Hardware-Based Scheduler For Next-Generation Optical Burst Switches.pdf
2007_04380686_ReconOS An RTOS Supporting Hard-and Software Threads.pdf
2007_04427426_Configurable Hardware-Software Support for Single Processor Real-Time Kernels.pdf

book
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관련있는지는 모르겠다..
Hardware Task Scheduling and Placement in Operating Systems for Dynamically Reconfigurable SoC
http://www.springerlink.com/content/y131m2q385003338/

 

SynthOS
이거는 HW OS가 아니네.. 알고보니 HW Synthesis 개념을 도입해서 C로 태스크레벨 작성하면서 SynthOS_Sleep();같은 함수 넣어놓으면 작성된 태스크에 맞춰서 최적화된 OS를 컴파일해주나보네.
http://www.zeidman.biz/synthos.htm
관련기사
http://www.embedded.com/news/embeddedindustry/170700476?_requestid=99771
http://www.pldesignline.com/206900555;jsessionid=2T3OSRT0HBBGEQSNDLQSKH0CJUNN2JVN?printableArticle=true