Changes between Version 1 and Version 2 of cypress/Programming/SpeedupScaling
- Timestamp:
- 08/18/15 12:24:51 (9 years ago)
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cypress/Programming/SpeedupScaling
v1 v2 2 2 = Parallel Computing = 3 3 == Moore's law == 4 [[Image(Moores_law_(1970-2011).png, 25%)]] 5 4 6 * 2X transistors/Chip Every 1.5 years Called “Moore’s Law” 5 7 * Microprocessors have become smaller, denser, and more powerful. … … 15 17 * When task switches occur frequently enough the illusion of parallelism is achieved. 16 18 19 [[Image(CPUpowerDensity.tiff)]] 17 20 18 21 == Multi-core == … … 26 29 A coprocessor is a computer processor used to supplement the functions of the primary processor (the CPU). Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, encryption or I/O Interfacing with peripheral devices. By offloading processor-intensive tasks from the main processor, coprocessors can accelerate system performance. 27 30 31 [[Image()]] 28 32 29 33 === GPU === 30 34 A graphics processing unit (GPU), also occasionally called visual processing unit (VPU), is a specialized electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display. GPUs are used in embedded systems, mobile phones, personal computers, workstations, and game consoles. Modern GPUs are very efficient at manipulating computer graphics, and their highly parallel structure makes them more effective than general-purpose CPUs for algorithms where processing of large blocks of data is done in parallel. In a personal computer, a GPU can be present on a video card, or it can be on the motherboard. 31 35 [[Image()]] 32 36 33 37 ==== GPU computing ==== … … 38 42 Intel Many Integrated Core Architecture or Intel MIC (pronounced Mick or Mike) is a coprocessor computer architecture developed by Intel, the Teraflops Research Chip multicore chip research project, and the Intel Single-chip Cloud Computer multicore microprocessor. 39 43 40 44 [[Image()]] 41 45 ---- 42 46 43 47 44 48 == Speedup Factor == 45 49 [[Image(Speedup_fac1.png)]] 46 50 * Suppose you have a code that takes ts~ seconds to run on one processor. 47 51 … … 65 69 66 70 This is the Amdahl's Law. 71 [[Image(Speedup_fac2.png)]] 72 73 == Overhead time == 74 75 * Since some extra procedures are required for parallelization, there are overheads of each parallel process. 76 * For MPI codes, the communication between processes is a major overhead. 77 * We can reduce this negative impact by overlapping communication with computations. 78 * For OpenMP, there are overhead time at the fork and join threads. 79 80 [[Image(Speedup_fac3.png)]]
