Outline  Over view  Design  Performance  Advantages and disadvantages  Examples  Conclusion  Bibliography

Multicore Processor Overview  A multi-core processor is composed of two or more independent cores. One can describe it as an integrated circuit which has two or more individual processors  Each core has it’s own complete set of resources, and may share the on-die cache layers

Windows Task Manager Core 1 Core 2

Why Using Multicore Processor Drawbacks of Unicore Processors  Difficult to make single-core clock frequencies even higher.  Many new applications are multithreaded  Deeply pipelined circuits :  Heat problems  Speed of light problems  Difficult design and verification  Large design teams necessary  Server farms need expensive air-conditioning

MOORE’S LAW  Moore's law describes a long-term trend in the history of computing hardware.  The number of transistors that can be placed inexpensively on an integrated circuit has doubled approximately every two years.  he trend has continued for more than half a century and is not expected to stop until 2015 or later.

DESIGN Single-core CPU Chip CPU chip bus interface ALUALU register file The single core System bus

Multi-core architecture  Replicate multiple processor cores on single die ALUALU ALUALU ALUALU ALUALU Bus interface Register file Multi-core CPU chip Core 2 Core 1 Core 3 Core 4

Multi-Core Processor Architecture of AMD

Architecture of Dual-Core Intel Processor  Two physical core in a package  Each with it’s own execution resources  Each with it’s own L1 cache  Both cores share the L2 cache  Truly parallel multi- tasking and threaded execution. Increased throughput..

Multi-core CPU chip core1core1 core2core2 core3core3 core4core4

Cores run in parallel core1core1 core2core2 core3core3 core4core4 thread 1 thread 2 thread 3 thread 4

Within each core, threads are time- sliced (just like on a uniprocessor) core1core1 core2core2 core3core3 core4core4 Several threads

Performance