SDP10_Final_Exam_Part2

Question 1

Question

Consider the following code. Assume the compiler is performing no optimization. Which of the following strategies would improve the speed of this code the most in the case where it returns true?

Image:

Booleanprime (binary/octet-stream)

Answer

Unroll the loop
Pull the (x % i)==0 into a function isDivisibleBy
Declare int sx = (int)sqrt(x) and change i < sqrt(x) to i < s
Move the check for (x % 2) != 0 to before the loop

Question 2

Question

By default, OpenMp _____ assigns loop iterations to threads. When the parallel for block is entered, it assigns each thread the set of loop iterations it is to execute?

Answer

static
runtime
dynamic
auto

Question 3

Question

OpenMP assigns one iteration to each thread. When the thread finishes, it will be assigned the next iteration that hasn’t been executed yet.

Answer

runtime
dynamic
static
auto

Question 4

Question

This is an example of? (IMAGE) /*set elements of array to 0*/ void clear_array (int *desc, int n){ int i; for (i = 0; i<n; i++) dest[i] = 0; } /*set elements of array to 0, Unrolled X4*/ ... ...

Image:

Loop Unrolling Example (binary/octet-stream)

Answer

Loop Unrolling
Loop fission
none
Loop fusion

Question 5

Question

This is an example of? (IMAGE) /*convert string to lowercase: slow*/ void lower1 (char *s) { int i; for (i = 0; i < strlen(s); i++) if (s{i} >= 'A' && s[i] <= 'Z') s[i] -= ('A' - 'a'); } /*Convert string to lowercase: faster*/ void lower2(char *s) { ... ... }

Image:

Codemotion Example (binary/octet-stream)

Answer

Loop fission
Code motion
Loop unrolling
Loop blocking

Question 6

Question

In given two C modules which rule will Unix linker use to resolve multiple symbol definition?

Image:

Pizdec (binary/octet-stream)

Answer

Given a strong symbol and multiple weak symbols, choose the strong symbol.
Given multiple weak symbols, chose any of the weak symbols
Multiple strong symbols are not allowed.
None of these

Question 7

Question

In C, on a 34-bit x86 machine, the expression (1<<31) results in a negative integer

Answer

True
False

Question 8

Question

Which of the following move operations is the following instruction an example of: movl (%edx), %eax ?

Answer

memory to immediate
register to memory
memory to register
error, can't move memory to memory

Question 9

Question

What is the value of the following C expression? x = 0xBC and y = 0x35 (x & !y)

Answer

0x1200
0xFFFF
0x0001
0x0000

Question 10

Question

In general, which of the following is slowest?

Answer

moving from one register to another
comparing two numbers to decide where to jump
doing division
accessing memory

Question 11

Question

Good software design includes writing procedures for code you might otherwise repeat in-line. Pulling code into procedures can help some branch predictors; how else can it improve your program’s performance and/or your compiler’s ability to optimize your code?

Answer

more opportunities for loop unrolling
less chance of compiler having to worry about aliasing and side effects
more opportunities for pipeline-level parallelism
better instruction cache hit rate

Question 12

Question

This is an example of?

Image:

Serial Comp1 (binary/octet-stream)

Answer

Parrallel processing
Serial processing
none of the above
Linear processing

Question 13

Question

This is an example of?

Image:

Paralllel Proc (binary/octet-stream)

Answer

Parallel processing
Serial processing
none of the above
Linear processing

Question 14

Question

The code ( a && b ) || (!a && !b) implements —

Answer

Equality
MUX
Adder
Set membership

Question 15

Question

Consider the following code fragment (IMAGE) int a; int b; int main(int argc, char * argv[]){ int x; int y; … /* some code*/ }

Image:

Motherfucker (binary/octet-stream)

Answer

The value of &y is closer to the value of &x than to the value &
The values of &a and &b are closer to each other then the values &x and &y
The values of *a and *b are closer to each other than the values of *x and *y
The value of *y is closer to the value of *x than to the value of *a

Question 16

Question

Compare the size of int and int*

Answer

each one of the above depends on the computer
int has fewer bits
int* has fewer bits
they have the same number of bits

Question 17

Question

In C, if x is an integer variable, the expression “x << 3” computes x * 8 but does not change the value of x.

Answer

true
false

Question 18

Question

Using a base address [Eb]%edx=0x1000, and index register [ei]%ecx=0x02, compute the effective address for (IMAGE) : movl 8(%edx,%ecx, 4), %eax)

Image:

Ebuieof (binary/octet-stream)

Answer

0x1032
0x1016
0x1064
0x1010

Question 19

Question

Using a base address [Eb]%edx=0x1000, and index register [ei]%ecx=0x03, compute the effective address for (IMAGE): movl 8(%edx, %ecx, 4), %eax

Image:

Ebuieof (binary/octet-stream)

Answer

0x1032
0x1016
0x1064
0x1014

Question 20

Question

What value ends up in EAX after the following code is executed?

Image:

Syntax (binary/octet-stream)

Answer

48 (decimal) or 00110000 (binary) or 0x30 (hex)
50 (decimal) or 00110010 (binary) or 0x32 (hex)
46 (decimal) or 00101110 (binary) or 0x2E (hex)
52 (decimal) or 00110100 (binary) or 0x34 (hex)

Question 21

Question

Two computers A and B with a cache in the CPU chip differ only in that A has an L2 cache and B does not. Which of the following are possible?

Image:

Twocomp (binary/octet-stream)

Answer

1 and 2 only
1 only
2 only
2 and 3 only

Question 22

Question

Which of the following code snippets is fastest ? Assume n is very large(more than ten thousand)

Answer

for(k=0; k<n; k+=16) for(l=0; l<n; l+=16) for(j=0;j<16;j+=1) for(i=0;i<16;i+=1) a[i+l][j+k] = b[j+k][i+l];
two or more of the above are equivalently the fastest
for(j=0;j<n;j+=1) for(i=0;i<n;i+=1) a[i][j] = b[j][i];
for(i=0;i<n;i+=1) for(j=0;j<n;j+=1) a[i][j] = b[j][i];

Question 23

Question

Which of the following code snippets is fastest? Assume n is very large (more than ten thousand).

Answer

for(i=0;i<n;i+=1) for(j=0;j<n;j+=1) a[i][j] = b[j][i];
for(j=0;j<n;j+=1) for(i=0;i<n;i+=1) a[i][j] = b[j][i
for(k=0; k<n; k+=16) for(l=0; l<n; l+=16) for(j=0;j<16;j+=1) for(i=0;i<16;i+=1) a[i+l][j+k] = b[i+l][j+k];
two or more of the above are equivalently the fastest

Question 24

Question

Good software design includes writing procedures for code you might otherwise repeat in-line. Pulling code into procedures involves call/return overhead; how else can it HURT your program's performance and/or your compiler's ability to optimize your code?

Answer

more chance of compiler having to worry about aliasing and side effects
fewer opportunities for pipeline-level parallelism
worse instruction cache hit rate
fewer opportunities for loop unrolling

Question 25

Question

Good software design includes writing procedures for code you might otherwise repeat in-line. Pulling code into procedures can help some branch predictors; how else can it IMPROVE your program’s performance and/or your compiler’s ability to optimize your code?

Answer

more opportunities for loop unrollin
less chance of compiler having to worry about aliasing and side effects
more opportunities for pipeline-level parallelism
better instruction cache hit rate

Question 26

Question

Consider a direct-mapped cache with 256 sets and 16 byte blocks. In this cache the address 0x12345 maps to the same set as which of the following addresses?

Answer

0x02345
0x22244
0x12354
0x12040

Question 27

Question

Parallel processing mechanisms to achieve parallelism in uniprocessor system are:

Answer

All of the above
Multiple function units
Parallelism and pipelining within CPU
Multiprogramming and time sharing

Question 28

Question

This is an example of?

Image:

Cpumem (binary/octet-stream)

Answer

Hybrid system
shared memory UMA
Distributed memory architecture
Shared memory NUMA

Question 29

Question

This is an example of? (IMAGE)

Image:

Loopfusion (binary/octet-stream)

Answer

None
Loop unrolling
Loop fusion
Loop fission

Question 30

Question

This is an example of?

Image:

Loopfission (binary/octet-stream)

Answer

Loop fission
Loop fusion
None
Loop unrolling

Question 31

Question

Program take as input a collection of relocatable object ﬁles and command-line arguments and generate as output a fully linked executable object ﬁle that can be loaded and run:

Answer

Static linker
Dynamic linker
Both
None

Question 32

Question

... involve identifying a computation that is performed multiple times (e.g., within a loop), but such that the result of the computation will not change.

Answer

Side effect
Code motion
Loop unrollin
Memory aliasing

Question 33

Question

... construct encloses code, forming a parallel region.

Answer

Parallel
Serial

Question 34

Question

... is the default schedule type. Upon entering the loop, each thread independently decides which chunk of the loop they will process.

Answer

static
dynamic
runtime
guided

Question 35

Question

By default, OpenMP _____ assigns loop iterations to threads. When the parallel for block is entered, it assigns each thread the set of loop iterations it is to execute?

Answer

static
dynamic
runtime
auto

Question 36

Question

The _______ directive causes threads encountering the barrier to wait until all the other threads in the same team have encountered the barrier.

Answer

single
barrier
nowait
private

	Created by Good Guy Beket almost 6 years ago

Next up

SDP10_Final_Exam_Part2

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Resource summary

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question 20

Question 21

Question 22

Question 23

Question 24

Question 25

Question 26

Question 27

Question 28

Question 29

Question 30

Question 31

Question 32

Question 33

Question 34

Question 35

Question 36

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