Introduction to performance optimization using Intel SW tools

Упражнение 1:

Номер 1

 What is the processor core?

Ответ:

(1) a part of the processor fetching and executing instructions

(2) a part of the processor working with shared cache

(3) a part of the processor executing arithmetical operations

Номер 2

What seriously limit modern system performance?

Ответ:

(1) memory amount

(2) processor cpu clock rate

(3) memory access speed

(4) 2 level cache existence

Номер 3

 What types multiprocessor systems could be divided into?

Ответ:

(1) shared memory systems

(2) distributed memory systems

(3) random memory access systems

(4) non-uniform memory access systems

Упражнение 2:

Номер 1

Choose the characteristic corresponding to distributed memory systems:

Ответ:

(1) Each processor is completely autonomous. There is a communications medium.

(2) All processors are equidistant from the memory. Communication with the memory via a common data bus.

(3) Memory is physically distributed among processors. Single address space is supported at the hardware level

Номер 2

 Choose the characteristic corresponding to shared memory systems:

Ответ:

(1) Each processor is completely autonomous. There is a communications medium

(2) All processors are equidistant from the memory. Communication with the memory via a common data bus

(3) Memory is physically distributed among processors. Single address space is supported at the hardware level

Номер 3

 Choose the characteristic corresponding to non-uniform memory access systems:

Ответ:

(1) Each processor is completely autonomous. There is a communications medium

(2) All processors are equidistant from the memory. Communication with the memory via a common data bus

(3) Memory is physically distributed among processors. Single address space is supported at the hardware level

Упражнение 3:

Номер 1

 What qualities does distributed memory systems have?

Ответ:

(1) good scalability

(2) different latency for the different parts of memory

(3) good inter processor communication

(4) the high cost of cache subsystem synchronization

Номер 2

 What qualities does shared memory systems have?

Ответ:

(1) good scalability

(2) different latency for the different parts of memory

(3) good inter processor communication

(4) the high cost of cache subsystem synchronization

Номер 3

 What qualities does non-uniform memory access systems have?

Ответ:

(1) good scalability

(2) different latency for the different parts of memory

(3) good inter processor communication

(4) the high cost of cache subsystem synchronization

Упражнение 4:

Номер 1

 What disadvantages does distributed memory systems have?

Ответ:

(1) slow inter processor communication

(2) poor scalability

(3) the high cost of cache subsystem synchronization

(4) different latency for the different parts of memory

Номер 2

 What disadvantages does shared memory systems have?

Ответ:

(1) slow inter processor communication

(2) poor scalability

(3) the high cost of cache subsystem synchronization

(4) different latency for the different parts of memory

Номер 3

 What disadvantages does non-uniform memory access systems have?

Ответ:

(1) slow inter processor communication

(2) poor scalability

(3) the high cost of cache subsystem synchronization

(4) different latency for the different parts of memory

Упражнение 5:

Номер 1

 What are multi-threading applications pros?

Ответ:

(1) memory amount is decreased according to the kernel count

(2) computational resources are increased according to the kernel count

(3) processor instruction set is decreased

Номер 2

 What are multi-threading applications cons?

Ответ:

(1) developing is more complex

(2) thread creation has its overhead

(3) memory amount is decreased according to the kernel count

(4) data races/ resource concurrency

(5) thread synchronization overhead

Упражнение 6:

Номер 1

 What is an automatic parallelization propose?

Ответ:

(1) to utilize multi-processor resources without code rewrite

(2) to make more qualified than manual parallelization

(3) to free programmer from the difficult and tedious manual parallelization

Номер 2

 What information does /Qpar-report3 output?

Ответ:

(1) information on dependencies prevent vectorization

(2) information on iteration order

(3) reasons preventing code parallelization

(4) informs whether the parallelization is unprofitable

Номер 3

 What kind of optimization is the auto-parallelization?

Ответ:

(1) loop non-permutation

(2) non-loop permutation

(3) loop permutation

(4) non-loop non-permutation

Упражнение 7:

Номер 1

What are necessary conditions for auto-parallelization?

Ответ:

(1) the absence of dependencies within the loop

(2) the absence of the loop nesting

(3) special manual preparation is always required

Номер 2

 Is it hard to measure optimization profitability?

Ответ:

(1) yes, because some performance effects are hard to estimate

(2) yes, because the iteration number can be unknown

(3) no, because auto-parallelization is loop permutation transformation

(4) no, because all the data are available at compile time

Номер 3

 What directive suggest the compiler to not parallelize following loop?

Ответ:

(1) #pragma prefer concurrent

(2) #pragma no concurrentize

(3) #pragma prefer serial

(4) #pragma serial

Упражнение 8:

Номер 1

 What directive will force compiler to parallelize following loop?

Ответ:

(1) #pragma concurrent call

(2) #pragma concurrentize

(3) #pragma prefer serial

(4) #pragma serial

Номер 2

 What directive will force compiler to parallelize following loop if it is safe?

Ответ:

(1) #pragma prefer concurrent

(2) #pragma concurrentize

(3) #pragma prefer serial

(4) #pragma serial

Номер 3

 What parallel library does Intel compiler use?

Ответ:

(1) OpenMP

(2) VTune

(3) STL

Упражнение 9:

Номер 1

 What is OpenMP?

Ответ:

(1) is a software interface that supports multi-platform programming for multiprocessor computation systems with shared memory

(2) is a software interface that checks parallelization correctness

(3) is a software interface to estimate parallelization profitability

Номер 2

 What is passed as an argument to loop parallelizing function in Intel compiler?

Ответ:

(1) loop boundaries

(2) only thread number to calculate the rest of parameters

(3) all used objects

Номер 3

 What is loop parallelizing function in Intel compiler?

Ответ:

(1) initial loop

(2) initial loop with bounds set by function parameters

(3) only one loop iteration

Упражнение 10:

Номер 1

 How parallelization in Intel compiler is implemented?

Ответ:

(1) The multiple instances of loop thread function are executed in different streams with different values of the boundaries

(2) Iterative loop space is divided into several parts and each is given to the separate thread

(3) Multiple function instances are run in the same thread with different values of the boundaries

(4) Iteration space is divided into parts, this parts are processed sequentially

Номер 2

 How auto-parallelization is connected with other optimizations in Intel compiler?

Ответ:

(1) when auto-parallelization is used no loop optimizations are available

(2) all loop optimizations are run before auto parallelization

(3) some loop optimizations are run after auto parallelization

Номер 3

 What is "prefetch"?

Ответ:

(1) loading data from relatively slow memory into the cache after the memory is required by processor

(2) loading data from cache into memory before the memory is required by processor

(3) loading data from relatively slow memory into the cache before the memory is required by processor

(4) memory address fetch before the memory will be required

Упражнение 11:

Номер 1

 How prefetch can be invoked?

Ответ:

(1) with compiler directive

(2) with compiler option for automatic instruction placement

(3) using intrinsic

(4) buying and installation of special prefetch program

Номер 2

 What cons does prefetch has?

Ответ:

(1) software prefetch may displace useful data out of the cache

(2) prefetch is ineffectively implemented and its usage will slow down the application

(3) hardware support is always required

Introduction to performance optimization using Intel SW tools - тест 6