FSKTM

Sistem-MultipemprosesApakah faedah sistem multi-pemproses?

....a LAN?

Memory Unit

CPU 1 CPU 2 CPU 3 IOP 1 IOP 2

...or a single system with many

processors?

FSKTM

Sistem Multipemproses

Sistem multipemproses yg sebenar ialah suatu sistem yg berbilang pemproses dlm satu hos yg sama, sama2 beroperasi utk mencapai truput yg lbh baik drps satu pemproses.

FSKTM

Approaches To Building Powerful Systems

• Penggunaan pendekatan single high performance processor memerlukan penekanan dan sokongan teknologi litar berkelajuan tinggi. Ini

• susah utk direkabentuk dan

• penyelenggaraannya mahal

• Senang digunakan jk dipandang dr sudut perisian.

atau

FSKTM

Approaches To Building Powerful Systems

•Menggunakan pendekatan multiple conventional processors, ini perlu memfokus kpd peningkatan truput dgn kaedah parallel processing.

• Pemproses individu tidak kompleks

• Parallel processing - ok tetapi,

• Sukar utk bhgkan aplikasi ke tugasan2 yg kecil supaya diproses serentak

• Penjadualan dan kordinasi memerlukan perisian yang sofisikated

FSKTM

Kebaikan Sistem Multi-pemproses

• Ekonomik yakni peningkatan keupayaan komputer dgn hanya sedikit kos tambahan(jk m’gunakan pemproses konventional yg murah)

• Meningkatnya kebolehpercayaan sistem disbbkan adanya lewahan (redundancy) (yakni multiple-processors).

FSKTM

Keburukkan Sistem Multi -pemproses

•Agihan tugasan2 antara pemproses2

•Salingsambungan ant pemproses (topologi)

•Pengurusan memori (dlm ertikata penggunaan memori) yg komplex

•avoidance of deadlock and control of I/O resources

•Senibina berkemungkinan sesuai bg masalah tertentu tapi bukan utk semua masalah.

FSKTM

Forms of Parallel Processing

• Single-Instruction Single-Data (SISD), a normal conventional single processor system

• Single-Instruction Multiple-Data (SIMD), memproses sacara tatasusun ‘array processing’, binaan disekitar pusat pemproses mengawal tatasusun bg special purpose processors

• Multiple-Instruction Single-Data (MISD), Secara teoritikal ia melaksanakan multi-operasi secara selasi dalam satu aliran data tunggal berserta dgn pemproses bertalianpaip. Buat masa ini tiada sistem berjenis ini.

• Multiple-Instruction Multiple-Data (MIMD), setiap pemproses mempunyai set arahan sendiri pada struktur datanya. Pemproses blh mencapai memori setempat yg lain melalui sistem I/O (Most of the commercial multiprocessor systems are of MIMD system).

FSKTM

Multiprocessor System Characteristics

• Gandingan ‘coupling’ ant pemproses2.

• Tightly coupled, pemproses2 direkabentuk supaya merujuk kpd common buses dan memory area (global memory) utk pertukaran large quantities of data yg bertubi-bertubi (pantas).

•Potential speed

•Complexity of the hardware and software

• Loosely coupled, pemproses2 melakukan pertukaran data melalui rangkaian I/O. Setiap pemprose ada memorinya sendiri.

•Slower data rate

•Simplifies the hardware design

FSKTM

Multiprocessor System Characteristics

• Topologi Sistem (paparan fizikal pemproses2), yakni bgmn pemproses2 disusun dan berkomunikasi diantara satu sama lain. Sistem multipemproses blh dikategori berdasarkan topologinya (method of interlinking the processors together). Topologi2nya ialah:-

• Time-shared common bus

• Multi-port memory

• Crossbar switch

• Multi-stage switching network

• Hyper-cube system

FSKTM

Time-Shared common bus

Memory Unit

CPU 1 CPU 2 CPU 3 IOP 1 IOP 2

The total overall transfer rate within the system is

very much restricted by the speed of the single path

FSKTM

Multiple Bus Structure

GlobalMemory

BusController

CPU IOPLocal

Memory

Local Bus

BusController CPU IOP

LocalMemory

Local Bus

System Bus

FSKTM

Multi-port Memory

CPU 1

MM1

CPU 2

CPU 3

CPU 4

MM2 MM3 MM4

FSKTM

Cross-bar Switch

CPU 1

MM1

CPU 2

CPU 3

CPU 4

MM2 MM3 MM4

Crossbar switch organization supports simultaneous transfers

from all memory modules because there

is a separate path associated with each

module

FSKTM

Multistage Switching Network

stage1 stage2 stage3

D0D1

D2D3

D4D5

D6D7

S0

S1

S2

S3

S4

S5

S6

S7

FSKTM

2 X 2 SwitchA

B

A

B

A

B

A

B

0

1

0

1

0

1

0

1

Operation of a 2 X 2 interchange switch

FSKTM

Hyper-cube System

• A hyper-cube system is a loosely coupled system which comprises of N (2n) processors in an n-dimensional cube form.For Example,If a system has sixteen (N) processors, the hyper-cube system is an n-dimensional system, whereby,N = 2n

2n =16n = log 16 log 2n = 4

FSKTM

Hyper-cube System

0

1

n = 1

(One Cube)

1101

00 10

n = 2

(Two Cube)

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Hyper-cube System

110 111

101100

010

000 001

011

The first practical hyper-cube was built in

1983 (Called the Cosmic Cube) and

was created using 64 units of the 8086 microprocessor

(together with the 8087 coprocessor)

FSKTM

Operating System

•Master/Slave OS, OS tuggal dilarikan pd master processor dan yg lain akan menerima tugasan daripadanya (slaves).

• Distributed OS, setiap pemproses melarikan Osnya sendiri, atau setiap pemproses boleh mencapai common OS melalui perkongsian memori. ( High Reliability)

FSKTM

Cache CoherencyIsu yang berkaitan dgn data disimpan dalam sistem multiprocessor, dan samada data didapati dr memori, sah atau tidak.

GlobalMemory

InterconnectionNetwork

CPU

CACHE

CPU

CACHE

FSKTM

Cache Coherency SolutionMethods of solving cache coherency problems:-

•Tidak membenarkan private cache, tumpukan kpd penggunaan shared cache area ( increases the average memory access time )

•Membenar penggunaan cache, ttp hy digunakan utk menyimpan data yg tidak dikongsi dan read only data ( cachable data )

•Membenarkan data dikongsi kecuali ttp hy satu pemproses blh Read/Write data dalam cachenya dalam satu masa.

•gunakan snoopy cache protocol (which is a hardware solution).