Transcript A Comparison of Parallel Sorting Algorithms on Different

A Comparison of Parallel Sorting Algorithms on
Different Architectures
Nancy M. Amato, Ravishankar Iyer, Sharad Sundaresan and Yan Wu
Texas A&M University
Hoang Bui
CMPS 5443
Overview
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Introduction
Machine Descriptions
Parallel Sorting Algorithms
Experimental Results
Comparisons and Recommendations
Introduction
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Sorting is one of the fundamental problems.
Sequential sorting and Parallel sorting.
Variety of parallel architectures.
Experimental study of three algorithms:
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Bitonic sort, sample sort & parallel radix sort.
Apply to three different machines.
Machine Descriptions
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The MasPar MP1201.
The nCUBE 2.
The Sequent Balance.
The MasPar MP1201
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SIMD machine.
2,048 processors, 1.8 MIPS, 16Kbytes RAM.
Mesh based architecture.
X-Net and Global Router for communication.
Programming languages: C-Like and Fortran.
The nCUBE 2
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MIMD machine.
64 processors, 7.5 MIPS 1Mbyte RAM.
Hypercube architecture.
Broadcasting.
Language: C.
The Sequent Balance
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MIMD.
Shared Memory
10 processors, 8 Kbytes RAM.
Communicate through shared memory.
Running Unix, language: C.
Parallel Sorting Algorithms
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Bitonic Sort.
Sample Sort.
Parallel Radix Sort.
Bitonic Sort
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Bitonic Sequence:
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Is the concatenation of an ascending and
descending sequence of numbers.
Example: 2,4,6,8,9,24,6,3,2,0.
Algorithm:
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Convert n numbers into a bitonic sequence with
n/2 numbers in an increasing subsequence.
Merge into an ordered sequence (increasing or
decreasing.)
Sample sort
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Algorithm:
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Select p-1 splitters  p buckets.
Each number is put into the appropriate bucket.
Sort each buckets.
Parallel Radix Sort
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Example list:
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170, 45, 75, 90, 2, 24, 802, 66
Algorithm:
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sorting by least significant digit (1s place) gives:
170, 90, 2, 802, 24, 45, 75, 66.
sorting by next digit (10s place) gives:
2, 802, 24, 45, 66, 170, 75, 90 .
sorting by most significant digit (100s place) gives:
2, 24, 45, 66, 75, 90, 170, 802
Experimental Results
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Make modifications to each machine.
Code was written in C.
Keys are randomly generated 32 bit integers.
Repeat 25 times and calculate the average.
The MasPar MP1202 – Bitonic sort
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Good speed-ups for all input size.
The MasPar MP1202 – Sample sort
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Also good speed-ups.
The MasPar MP1202 – Radix sort
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Shortest time for the MasPar MP1202.
The MasPar MP1202
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Comparisons:
The nCUBE 2 – Bitonic Sort
The nCUBE 2 – Sample Sort
The nCUBE 2 – Radix Sort
The nCUBE 2
The Sequent Balance – Bitonic sort
The Sequent Balance – Sample sort
The Sequent Balance – Radix sort
The Sequent Balance
Comparisons and Recommendations
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MasPar MP1202:
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nCUBBE 2:
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Bitonic Sort for smaller input size.
Parallel Radix Sort for larger input size.
Sample Sort is the best.
Sequent Balance:
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Sample Sort for smaller input size.
Parallel Radix Sort for larger input size.
Question