Speed up - metrics for performance evaluation, Computer Engineering

Assignment Help:

Q. Speed Up - metrics for performance evaluation?

Speed up is ratio of time needed to execute a given program employing a specific algorithm on a machine with single processor (It implies that T (1) (where n=1)) to time needed to execute same program using a particular algorithm on a machine with multiple processors (It implies that T (n)). Fundamentally speed up factor helps us in knowing relative gain achieved in shifting from a sequential machine to a parallel computer. It can be noted the term T(1) denotes amount of time taken to execute a program employing the best sequential algorithm It implies that the algorithm with least time complexity. 

2366_Speed Up - metrics for performance evaluation.png

Let's take an illustration and explain practical use of speedup. Suppose we have a problem of multiplying n numbers. Time complexity of sequential algorithm for a machine with single processor is O(n) because we require one loop for reading and computing output. But in the parallel computer let every number is assigned to specific processor and computation model being used being a hypercube. In such a condition the total number of steps essential to compute result is log n it implies that time complexity is O(log n). Figure below explains the steps to be followed for achieving the required output in a parallel hypercube computer model.

As number of steps followed is equivalent to 3 it implies that log 8 where n is number of processors. Therefore complexity is O(log n). 

In view of fact sequential algorithm takes 8 steps whereas above mentioned parallel algorithm takes 3 steps speed up is as under:

1715_Speed Up - metrics for performance evaluation1.png

Because value of S(n) is inversely proportional to time needed to calculate output on a parallel number that in turn is dependent on number of processors used for performing the computation. The relation amid S(n) versus Number of processors is displayed in Figure. The speedup is directly proportional to number of processors so a linear arc is portrayed. But in situations where there is parallel overhead the arc is sub-linear.

716_Speed Up - metrics for performance evaluation3.png

Figure: Steps followed for multiplying n numbers stored on n processors

295_Speed Up - metrics for performance evaluation2.png

Figure: Speed-up vs. Number of Processors


Related Discussions:- Speed up - metrics for performance evaluation

What is a javabean, JavaBeans are reusable software components written in t...

JavaBeans are reusable software components written in the Java programming language, designed to be influenced visually by a software development environment, like JBuilder or Visu

Define the time when a block of data is ready to be read, The total time to...

The total time to prepare a disk drive mechanism for a block of data to be read from is its ? Ans. latency plus seek time is the total time to prepare a disk drive mechanism fo

Define protocol, Define Protocol. It is a set of rules that are followe...

Define Protocol. It is a set of rules that are followed by interconnecting computers and terminals to make sure the orderly transfer of information

Explain program level of parallel processing, Program Level This is nor...

Program Level This is normally the liability of OS (operating system) that runs processes simultaneously. Different programs are generally independent of each other. So paralle

What is the function of the correction system, What is the function of the ...

What is the function of the correction system? The correction system handles changes to internal system components. Like as objects of the ABAP/4 Dictionary.

Determine the uses of defparam, Using defparam Parameter values can be ...

Using defparam Parameter values can be changed in any module instance in the design with keyword defparam. Hierarchical name of the module instance can be used to override para

System software, what can be the good projects for system software subject

what can be the good projects for system software subject

Which of the memories stores the most number of bits, Which of the memories...

Which of the memories stores the most number of bits ? Ans. most number of bits stores in 32M x 8 As 2 5 x 2 20   = 2 25 Therefore 1M = 2 20 = 1K x 1K = 2 10 x 2 10

What is a reference string, What is a reference string? An algorithm is...

What is a reference string? An algorithm is evaluated by running it on a exacting string of memory references and computing the number of page faults. The string of memory refe

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd