Computer Architecture

1. Multi-Core Processor
Prepared by
Dr.S.Raja Ratna
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Multicore Processor
• A multi-core processor is an integrated circuit with two or more
processors connected to it for faster simultaneous processing of
several tasks, reduced power consumption, and for greater
performance.
• It is made up of two or more processors that read and execute
program instructions.
• On a single chip, a multi-core processor comprises numerous
processing units, or "Cores," each of which has the potential to do
distinct tasks.

3. Architecture of Multicore Processor
• A multicore processor design enables the communication between all
available cores, and they divide and assign all processing duties.
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4. Advantages of Multi-Core Processor
• Performance
• Reliability
• Software Interactions
• Multitasking
• Power Consumption
• Obsolescence Avoidance
• Isolation
• When compared to single-core processors, a multicore processor has
the potential of doing more tasks.
• Low energy consumption when doing many activities at once.
• Data takes less time to reach its destination since both cores are
integrated on a single chip.
• With the use of a small circuit, the speed can be increased.
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5. Multi-Core Processor
• For instance, if you are performing many tasks at once, such as
watching a movie and using WhatsApp, one core will handle activities
like watching a movie while the other handles other responsibilities like
WhatsApp.
• The processed data from each core is transmitted back to the
computer's main board (Motherboard) via a single common gateway
once all of the processing operations have been finished. This method
beats a single-core CPU in terms of total performance.
• These processors also enable more efficient simultaneous processing
of multiple tasks, such as with parallel processing and Multithreading.
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Multi core Processor
• The cores fit on a single processor socket
• Also called CMP (Chip Multi-Processor)
• OS perceives each core as a separate processor
• OS scheduler maps threads/processes to different cores

7. Multi core Processor
• Within each core, threads are time-sliced (just like on a
uniprocessor).
• Most major OS support multi-core today: Windows, Linux, Mac
OS X, etc…
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8. Instruction-level parallelism
• Parallelism at the machine-instruction level
• The processor can re-order, pipeline instructions, split them into
microinstructions, do aggressive branch prediction, etc.
• Instruction-level parallelism enabled rapid increases in processor
speeds over the last 15 years.
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9. Thread-level parallelism (TLP)
• This is parallelism on a more coarser scale.
• Server can serve each client in a separate thread (Web server,
database server)
• A computer game can do AI, graphics, and physics in three
separate threads
• Single-core superscalar processors cannot fully exploit TLP
• Multi-core architectures are the next step in processor evolution:
explicitly exploiting TLP
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