Deck 13: Parallel Communication and Runtime Analysis

Question 1

In All-to-All Personalized Communication on a Ring, the size of the message reduces by___________      at each step

A)p
B)m-1
C)p-1
D)m

Answer 1

p

Question 2

All-to-All Broadcast and Reduction algorithm on a Ring terminates in___________           steps.

A)p+1
B)p-1
C)p*p
D)p

Answer 2

p*p

Question 3

In All-to-all Broadcast on a Mesh, operation performs in which sequence?

A)rowwise, columnwise
B)columnwise, rowwise
C)columnwise, columnwise
D)rowwise, rowwise

Answer 3

columnwise, rowwise

Question 4

Messages get smaller in and stay constant in .

A)gather, broadcast
B)scatter , broadcast
C)scatter, gather
D)broadcast, gather

Question 5

The time taken by all-to- all broadcast on a ring is .

A)t= (ts + twm)(p-1)
B)t= ts logp + twm(p-1)
C)t= 2ts(?p - 1) - twm(p-1)
D)t= 2ts(?p - 1) + twm(p-1)

Question 6

The time taken by all-to- all broadcast on a mesh is .

A)t= (ts + twm)(p-1)
B)t= ts logp + twm(p-1)
C)t= 2ts(?p - 1) - twm(p-1)
D)t= 2ts(?p - 1) + twm(p-1)

Question 7

The time taken by all-to- all broadcast on a hypercube is .

A)t= (ts + twm)(p-1)
B)t= ts logp + twm(p-1)
C)t= 2ts(?p - 1) - twm(p-1)
D)t= 2ts(?p - 1) + twm(p-1)

Question 8

The prefix-sum operation can be implemented using the kernel

A)all-to-all broadcast
B)one-to-all broadcast
C)all-to-one broadcast
D)all-to-all reduction

Question 9

Select the parameters on which the parallel runtime of a program depends.

A)number of processors
B)communication parameters of the machine
C)all of the above
D)input size

Question 10

The time that elapses from the moment the first processor starts to the moment the last processor finishes execution is called as___________               .

A)parallel runtime
B)overhead runtime
C)excess runtime
D)serial runtime

Question 11

Select how the overhead function (To) is calculated.

A)to = p*n tp - ts
B)to = p tp - ts
C)to = tp - pts
D)to = tp - ts

Question 12

What is is the ratio of the time taken to solve a problem on a single processor to the time required to solve the same problem on a parallel computer with p identical processing elements?

A)overall time
B)speedup
C)scaleup
D)efficiency

Question 13

Which is alternative options for latency hiding?

A)increase cpu frequency
B)multithreading
C)increase bandwidth
D)increase memory

Question 14

______ Communication model is generally seen in tightly coupled system.

A)message passing
B)shared-address space
C)client-server
D)distributed network

Question 15

The principal parameters that determine the communication latency are as follows:

A)startup time (ts) per-hop time (th) per-word transfer time (tw)
B)startup time (ts) per-word transfer time (tw)
C)startup time (ts) per-hop time (th)
D)startup time (ts) message-packet-size(w)

Question 16

The number and size of tasks into which a problem is decomposed determines the __

A)granularity
B)task
C)dependency graph
D)decomposition

Question 17

Average Degree of Concurrency is...

A)the average number of tasks that can run concurrently over the entire duration of execution of the process.
B)the average time that can run concurrently over the entire duration of execution of the process.
C)the average in degree of task dependency graph.
D)the average out degree of task dependency graph.

Question 18

Which task decomposition technique is suitable for the 15-puzzle problem?

A)data decomposition
B)exploratory decomposition
C)speculative decomposition
D)recursive decomposition

Question 19

Which of the following method is used to avoid Interaction Overheads?

A)maximizing data locality
B)minimizing data locality
C)increase memory size
D)none of the above.

Question 20

Which of the following is not parallel algorithm model

A)the data parallel model
B)the work pool model
C)the task graph model
D)the speculative model

Question 21

Nvidia GPU based on following architecture

A)mimd
B)simd
C)sisd
D)misd

Question 22

What is Critical Path?

A)the length of the longest path in a task dependency graph is called the critical path length.
B)the length of the smallest path in a task dependency graph is called the critical path length.
C)path with loop
D)none of the mentioned.

Question 23

Which decompositioin technique uses divide-andconquer strategy?

A)recursive decomposition
B)sdata decomposition
C)exploratory decomposition
D)speculative decomposition

Question 24

Consider Hypercube topology with 8 nodes then how many message passing cycles will require in all to all broadcast operation?

A)the longest path between any pair of finish nodes.
B)the longest directed path between any pair of start & finish node.
C)the shortest path between any pair of finish nodes.
D)the number of maximum nodes level in graph.

Question 25

Scatter is ____________.

A)one to all broadcast communication
B)all to all broadcast communication
C)one to all personalised communication
D)node of the above.