Multi Core processors Multiple Choice Questions
1. The idea of cache memory is based
A. on the property of locality of reference
B. on the heuristic 90-10 rule
C. on the fact that references generally tend to cluster
D. all of the above
Answer: C. on the fact that references generally tend to cluster
2. Systems that do not have parallel processing capabilities are
A. sisd
B. mimd
C. simd
D. misd
Answer: D. misd
3. Parallel programs: Which speedup could be achieved according to Amdahl´s law for infinite number of processors if 5% of a program is sequential and the remaining part is ideally parallel?
A. 10
B. 20
C. 30
D. 40
Answer: B. 20
4. In shared bus architecture, the required processor(s) to perform a bus cycle, for fetching data or instructions is
A. one processor
B. two processor
C. multi-processor
D. none of the above
Answer: C. multi-processor
5. Alternative way of a snooping-based coherence protocol, is called a
A. write invalidate protocol
B. snooping protocol
C. directory protocol
D. write update protocol
Answer: C. directory protocol
6. If no node having a copy of a cache block, this technique is known as
A. cached
B. un-cached
C. shared data
D. valid data
Answer: D. valid data
7. All nodes in each dimension form a linear array, in the .
A. star topology
B. ring topology
C. connect topology
D. mesh topology
Answer: D. mesh topology
8. tasks being performed in different stages :
A. require different amount of time
B. require about the same amount of time
C. require different amount of time with time difference between any two tasks being same
D. require different amount with time difference between any two tasks being different
Answer: A. require different amount of time
9. The expression ‘delayed load’ is used in context of
A. processor-printer communication
B. memory-monitor communication
C. pipelining
D. none of the above
Answer: C. pipelining
10. During the execution of the instructions, a copy of the instructions is placed in the .
A. register
B. ram
C. system heap
D. cache
Answer: C. system heap
11. Producer consumer problem can be solved using
A. semaphores
B. event counters
C. monitors
D. all of the above
Answer: C. monitors
12. A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called:
A. data consistency
B. race condition
C. aging
D. starvation
Answer: B. race condition
13. Which one of the following statements describes the properties achieved?
A. mutual exclusion but not progress
B. progress but not mutual exclusion
C. neither mutual exclusion nor progress
D. both mutual exclusion and progress
Answer: A. mutual exclusion but not progress
14. All deadlocks involve conflicting needs for
A. resources
B. users
C. computers
D. programs
Answer: A. resources
15. To avoid deadlock
A. there must be a fixed number of resources to allocate
B. resource allocation must be done only once
C. all deadlocked processes must be aborted
D. inversion technique can be used
Answer: A. there must be a fixed number of resources to allocate
16. processes to solve the critical section problem.
A. one
B. two
C. three
D. four
Answer: B. two
17. Spinlocks are intended to provide only.
A. mutual exclusion
B. bounded waiting
C. aging
D. progress
Answer: B. bounded waiting
18. A semaphore is a shared integer variable .
A. lightweight process
B. that cannot drop below zero
C. program counter
D. stack space
Answer: B. that cannot drop below zero
19. A critical section is a program segment .
A. where shared resources are accessed
B. single thread of execution
C. improves concurrency in multi-core system
D. lower resource consumption
Answer: D. lower resource consumption
20. A counting semaphore was initialized to 10. Then 6 P (wait) operations and 4V (signal) operations were completed on this semaphore. The resulting value of the semaphore is
A. 4
B. 6
C. 9
D. 8
Answer: D. 8
21. How many times will process P0 print ‘0’?
A. at least twice
B. one
C. three
D. none of the above
Answer: C. three
22. A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units, then
A. better system utilization
B. deadlock can never occur
C. responsiveness
D. faster execution
Answer: C. responsiveness
23. code, resources or data in such a way that only one process has access to shared object at a time.
A. readers_writer locks
B. barriers
C. semaphores
D. mutual exclusion
Answer: C. semaphores
24. is the ability of multiple processes to co-ordinate their activities by exchange of information.
A. deadlock
B. synchronization
C. mutual exclusion
D. cache
Answer: A. deadlock
25. Paths that have an unbounded number of allowed nonminimal hops from packet sources, this situation is referred to as .
A. livelock
B. deadlock
C. synchronization
D. mutual exclusion
Answer: C. synchronization
26. Let S and Q be two semaphores initialized to 1, where P0 and P1 processes the following statements wait(S);wait(Q); —; signal(S);signal(Q) and wait(Q); wait(S);—;signal(Q);signal(S); respectively. The above situation depicts a .
A. livelock
B. critical section
C. deadlock
D. mutual exclusion
Answer: C. deadlock
27. Which of the following conditions must be satisfied to solve the critical section problem?
A. mutual exclusion
B. progress
C. bounded waiting
D. all of the mentioned
Answer: D. all of the mentioned
28. a process is allowed to enter its critical section .
A. after a process has made a request to enter its critical section and before the request is granted
B. when another process is in its critical section
C. before a process has made a request to enter its critical section
D. none of the mentioned
Answer: A. after a process has made a request to enter its critical section and before the request is granted
29. processes to solve the critical section problem.
A. one
B. two
C. three
D. four
Answer: B. two
30. What are Spinlocks?
A. cpu cycles wasting locks over critical sections of programs
B. locks that avoid time wastage in context switches
C. locks that work better on multiprocessor systems
D. all of the mentioned
Answer: D.all of the mentioned
31. What is the main disadvantage of spinlocks?
A. they are not sufficient for many process
B. they require busy waiting
C. they are unreliable sometimes
D. they are too complex for programmers
Answer: B.they require busy waiting
32. at any moment (the mutex being initialized to 1)?
A. 1
B. 2
C. 3
D. none of the mentioned
Answer: C.3
33. Here, w1 and w2 have shared variables, which are initialized to false. Which one of the following statements is TRUE about the above construct?
A. it does not ensure mutual exclusion
B. it does not ensure bounded waiting
C. it requires that processes enter the critical section in strict alternation
D. it does not prevent deadlocks but ensures mutual exclusion
Answer: D.it does not prevent deadlocks but ensures mutual exclusion
34. The signal operation of the semaphore basically works on the basic system call.
A. continue()
B. wakeup()
C. getup()
D. start()
Answer: B.wakeup()
35. (not necessarily immediately)?
A. #pragma omp section
B. #pragma omp parallel
C. none
D. #pragma omp master
Answer: A. #pragma omp section
36. When compiling an OpenMP program with gcc, what flag must be included?
A. -fopenmp
B. #pragma omp parallel
C. –o hello
D. ./openmp
Answer: A. -fopenmp
37. program, i.e., each thread executes the same code.
A. parallel
B. section
C. single
D. master
Answer: A. parallel
38. they would be in serial program.
A. no wait
B. ordered
C. collapse
D. for loops
Answer: B. ordered
39. code of functions that are called (directly or indirectly) from within the parallel region.
A. lexical extent
B. static extent
C. dynamic extent
D. none of the above
Answer: C. dynamic extent
40. The specifies that the iterations of the for loop should be executed in parallel by multiple threads.
A. sections construct
B. for pragma
C. single construct
D. parallel for construct
Answer: B. for pragma
41. active in the parallel section region.
A. omp_get_num_procs ( )
B. omp_get_num_threads ( )
C. omp_get_thread_num ( )
D. omp_set_num_threads ( )
Answer: B. omp_get_num_threads ( )
42. The size of the initial chunksize .
A. total_no_of_iterations / max_threads
B. total_no_of_remaining_iterations / max_threads
C. total_no_of_iterations / no_threads
D. total_no_of_remaining_iterations / no_threads
Answer: A. total_no_of_iterations / max_threads
43. parallel architectures affect parallelization?
A. performance
B. latency
C. bandwidth
D. accuracy
Answer: C. bandwidth
44. global_count += 5;
A. 4 instructions
B. 3 instructions
C. 5 instructions
D. 2 instructions
Answer: C. 5 instructions
45. generate log files of MPI calls.
A. mpicxx
B. mpilog
C. mpitrace
D. mpianim
Answer: B.mpilog
46. selectively screen messages.
A. dest
B. type
C. address
D. length
Answer: B.type
47. them in this case and returning the result to a single process.
A. mpi _ reduce
B. mpi_ bcast
C. mpi_ finalize
D. mpi_ comm size
Answer: A.mpi _ reduce
48. The easiest way to create communicators with new groups is with .
A. mpi_comm_rank
B. mpi_comm_create
C. mpi_comm_split
D. mpi_comm_group
Answer: C.mpi_comm_split
49. is an object that holds information about the received message, including, for example, it’s actually count.
A. buff
B. count
C. tag
D. status
Answer: D.status
50. The operation similarly computes an element-wise reduction of vectors, but this time leaves the result scattered among the processes.
A. reduce-scatter
B. reduce (to-one)
C. allreduce
D. none of the above
Answer: A.reduce-scatter
51. is applicable in ___________________.
A. amdahl\s law
B. gustafson-barsis\s law
C. newton\s law
D. pascal\s law
Answer: A. amdahl\s law
52. programming. The issues related to synchronization include the followings, EXCEPT:
A. deadlock
B. livelock
C. fairness
D. correctness
Answer: C. fairness
53. Interface (MPI)?
A. a specification of a shared memory library
B. mpi uses objects called communicators and groups to define which collection of processes may communicate with each other
C. only communicators and not groups are accessible to the programmer only by a “handle”
D. a communicator is an ordered set of processes
Answer: C. only communicators and not groups are accessible to the programmer only by a “handle”
54. workload in the computation of the forces.
A. cyclic distribution
B. velocity of each particle
C. universal gravitation
D. gravitational constant
Answer: B. velocity of each particle
55. parallelizing them using OpenMP.
A. thread‘s rank
B. function loopschedule
C. pthreads
D. loop variable
Answer: D. loop variable
56. Each node of the tree has an , that is, the cost of the partial tour.
A. euler‘s method
B. associated cost
C. three-dimensional problems
D. fast function
Answer: C. three-dimensional problems
57. could possibly lead to a least-cost solution.
A. depth-first search
B. foster‘s methodology
C. reduced algorithm
D. breadth first search
Answer: C. reduced algorithm
58. user program and buffer size is its size in bytes.
A. tour data
B. node tasks
C. actual computation
D. buffer argument
Answer: A. tour data
59. addition to the cost of the communication, the packing and unpacking is very .
A. global least cost
B. time- consuming
C. expensive tours
D. shared stack
Answer: C. expensive tours
60. has in its stack.
A. terminated
B. send rejects
C. receive rejects
D. empty
Answer: D. empty
61. takes the data in data to be packed and packs it into
A. mpi unpack
B. mpi_pack
C. mpi_datatype
D. mpi_comm
Answer: C. mpi_datatype