Computer architecture multi core processor

Computer Architecture multi core processor seminar
Mustansiriya University
Department of Education
Computer Science

1. Presented by : Sahar MULTI CORE POCESSOR

2. Introduction: What is Processor? A  processor  is the logic circuitry that responds to and processes the basic instructions that drive a computer. The term  processor  has generally replaced the term central processing unit ( CPU ). The  processor  in a personal computer or embedded in small devices is often called a microprocessor .

3. What Is Core? Actually, a CORE is the part of something that is central to its existence or character. Similarly, in computer system the CPU is referred as CORE. Basically, there are two types of core processor: 1. Single Core Processor 2. Multi Core Processor

4. Single Core processor It is a processor that has only one core, so it can only start one operation at a time. It can however in some situations start a new operation before the previous one is complete. Originally all processors were single core. Examples are Intel Pentium 4 670, AMD Athlon 64 FX-55.

5. Multi Core Processor A multi-core processor is one which combines two or more independent processors into a single package, often a single integrated circuit. Examples are Intel core i7, intel core 2 duo.

6. Processor consists: A single chip package that fits in a socket Cores can have functional units, cache, etc. associated with them, just as today Cores can be fast or slow, just as today Shared resources More cache Other integration: Northbridge, memory controllers, high-speed serial links, etc. One system interface for System Bus and System Memory

7. Problems with Single Core To execute the tasks faster you must increase the clock time. Increasing clock times too high drastically increases power consumption and heat dissipation to extremely high levels, making the processor inefficient

8. Multi Core solution Creating two cores or more on the same Die increases processing power while keeping clock speeds at an efficient level. A processor with 2 cores running at efficient clock speeds can process instructions with similar speed to a single core processor running at twice the clock speed, yet the dual core processor would still consume less energy.

9. Why Multi-core? Better Performance For the Multi tasking e.g. Burning CD with graphic works at the same time Power consumption and Heat generation C aused from the advance of CPU clock speed

10. Why Multi-core? Save the room of motherboard Two single cores → In one die We can use this room more efficiently Simplicity We need additional systems to control the several single cores. Economical efficiency A dual-core is much cheaper than two single cores

11. If multi means two or more, what types are there? A dual-core processor A quad-core processor contains two cores contains four cores

12. Multicore Organization Number of core processors on chip Number of levels of cache on chip Amount of shared cache

13. Shared caches As the trend moves from single-core to multi-core processors for the next computing performance leap, system architectures have several options for the organization of one of the most important system resources-the cache. Some architectures choose to keep the last-level cache private to each core for simplicity, while other architectures explore sharing the last-level cache among different cores for better performance/cost ratio and improved resource allocation.

14. Benefits of the shared cache architecture Figure 1 shows two processors (processor 0 and processor 1) sharing the same system bus and system memory. Inside each processor there are two CPU cores; each has its own private L1 cache while sharing the L2 cache. The benefits of such a shared cache system are many:

15. Benefits of the shared cache architecture Efficient usage of the last-level cache If one core idles, the other core takes all the shared cache Reduces resource underutilization Flexibility for programmers Allows more data-sharing opportunities for threads running on separate cores that are sharing cache One core can pre-/post-process data for the other core Alternative communication mechanisms between cores

16. Benefits of the shared cache architecture (cont) Reduce cache-coherency complexity Reduced false sharing because of the shared cache Less workload to maintain coherency, compared to the private cache architecture Reduce data-storage redundancy The same data only needs to be stored once

17. Benefits of the shared cache architecture (cont) Reduce front-side bus traffic Effective data sharing betw een cores allows data requests to be resolved at the shared-cache level instead of going all the way to the system memory

18. Multi-core Organization (cont…)

19. Cache coherence “ For any given memory location, at any given (logical) time, there is either a single core that may write it (and that may also read it) or some number of cores that may read it. ” Cache coherence: definition Two fundamental invariants: ● Single-Writer-Multiple-Reader (SWMR) ● Data-Value

20. Cache Consistency A specification of the allowed behavior of multithreaded programs executing with shared memory ● Multiple correct behaviors are usually allowed One fundamental: ● Out-of-Order execution

21. Performance Enhancement Pipelining concept used i.e. subsequent instruction begins to execute before completion of the previous one or allowing parallel processing.

22. Performance Enhancement Contd. Multithreading i.e. time is divided and interlaced between more than one thread to simulate simultaneous execution.

23. Applications of Multicore 3D Gaming Database servers Multimedia applications Video editing Powerful graphics solution Encoding Computer Aided Design (CAD)

24. Advantages Signals between different CPUs travel shorter distances, those signals degrade less. These higher quality signals allow more data to be sent in a given time period since individual signals can be shorter and do not need to be repeated as often. A dual-core processor uses slightly less power than two coupled single-core processors. More features can be added to the computer

25. Disadvantages They do not work at twice the speed as a normal processor . They get only 60-80% more speed. The speed that the computer works at depends on what the user is doing with it. They cost more than single core processors. They are more difficult to manage thermally than lower-density single-core processors.

26. EXAMPLES dual- core processor with 2 cores e.g . AMD Phenom II X2, Intel Core 2 Duo E8500 quad-core processor with 4 cores e.g. AMD Phenom II X4, Intel Core i5 2500T) hexa -core processor with 6 cores e.g. AMD Phenom II X6, Intel Core i7 Extreme Ed. 980X octa-core processor with 8 cores e.g . AMD FX-8150, Intel Xeon E7-2820

27. Thank You