Multi-core Processor

Jia Yao

ECE Dep. Auburn University

What is a multi-core processor ? A processing system composed of two or

more independent cores, which facilitates simultaneous managing of activities.

CPU1 and

L1 Cache

CPU2 and

L1 Cache

L2 Cache

Main Memory

Dual-core Architecture

Dual-core and quad-core processor

High performance without driving up power consumption

Multi-core processor history Motivated by increasing operating frequency, which

leads to increasing gap between processor and memory speeds, larger cache, higher power consumption.

The world’s first multi-core processor is “Power4” released by IBM in 2001.

IBM Power4, Power5, Power6, PowerPC

AMD Athlon, Opteron, Phenom

Intel Core 2 Duo, Core 2 Quad, Xeon

Nvidia Geforce9, Geforce200

Sun microsystem MARJC, UltraSPARC

Advantages ?

Single-core

Large tasks running simultaneously slow down

Dual-core

Large tasks can be processed in separate CPUs

CPU

CPU1 CPU2

How does multi-core processor work?

Significant improvement on cache (bus) snooping

Signals between different CPUs travel shorter distance, which allows more date sent in one period, less signal degradation, does not need to sent data repeatedly as often

CPU1 and

L1 Cache

CPU2 and

L1 Cache

L2 Cache

Main Memory

1 + 1 = 2?

Not exactly, 1+1=1.5

Future Development

Low Power Design

power consumption doubles with each doubling of operating frequency

Software support

Such like more intelligent compiler which is capable of sending balanced load of instructions to individual cores.

Reference

[1] http://en.wikipedia.org/wiki/Multi-core [2]http://www.dell.com/downloads/global/power/ps2q

05-20050103-Fruehe.pdf [3]http://multicore.amd.com/Resources/33211A_Mult

i-Core_WP_en.pdf [4] http://www.intel.com/multi-core [5] http://www.bitpipe.com/tlist/Multi-core-Processor-A

rchitecture.html