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

How to calculate colour depth, Q. How to calculate Colour Depth? Colour...

Q. How to calculate Colour Depth? Colour Depth (or number of Colour Planes) is number of bits assigned to every pixel to code colour information in it. These are also known as

What is meant by the guest function, When  transferring  one  functio...

When  transferring  one  function  to  another,  what  is  meant  by  the  guest  function? A pointer to a function can be passed to another function as an argument. This allows

What is a table pool, What is a table pool? A table pool (or pool) is ...

What is a table pool? A table pool (or pool) is used to join several logical tables in the ABAP/4 Dictionary.  The definition of a pool having of at least two key fields and a

Explain the concept of thread, The Concept of Thread A thread is a sequ...

The Concept of Thread A thread is a sequential flow of control within a process. A process is able to have one or more threads. Threads have their own register-values and progr

Describe about relationships and look up fields, Relationships are imported...

Relationships are imported from the source to finish without any hindrance but once they land in the destination they can never be changed or changed and change of extensions canno

What is a word line, What is a word line? In a memory cell, all the cel...

What is a word line? In a memory cell, all the cells of a row are linked to a common line called as word line

Describe about minicomputers, Q. Describe about Minicomputers? Minicomp...

Q. Describe about Minicomputers? Minicomputers, developed in the early 1960s, are high-performance, general-purpose multi user computers. These are also designed for real-tim

What is the bios full form, BIOS - Basic Input Output System, Power On ...

BIOS - Basic Input Output System, Power On Self Test (POST) and Loading Bootloader from the Hard disk drive Boot Sector is being completed by BIOS. It started the system for

What do you mean by directives, Q What do you mean by Directives? Assem...

Q What do you mean by Directives? Assembly languages support numerous statements. This allows you to control the way in which a source program assembles and list. These stateme

Serialized when you perform serialization, What exactly is being serialized...

What exactly is being serialized when you perform serialization? Serialization is the process of changing an object into stream of bytes. We perform it at the time of transpor

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