MCQs on Optimizing Performance | Haskell
Optimizing performance in Haskell is crucial for building efficient applications. Haskell provides tools and techniques for profiling performance, managing memory, and minimizing space leaks. Understanding strictness annotations, using seq, and advanced memory management techniques in GHC (Glasgow Haskell Compiler) are key elements for enhancing Haskell performance. This set of 30 multiple-choice questions (MCQs) covers these essential topics in Haskell programming, helping you master performance optimization.
MCQs on Optimizing Performance in Haskell Programming
Performance Profiling in Haskell
- Which Haskell tool is primarily used for performance profiling?
- a) GHCi
- b) HProf
- c) GHC’s built-in profiler
- d) Haskell Profiler
- In Haskell, what does the
+RTS -pflag do?- a) It starts the program with optimizations enabled
- b) It generates a performance profile report
- c) It disables garbage collection
- d) It checks the syntax of the program
- What information is typically found in a performance profile generated by GHC?
- a) Function call counts and memory usage
- b) Source code syntax errors
- c) Number of exceptions thrown
- d) Information about the type system
- Which of the following GHC profiling options helps identify which parts of the program use the most memory?
- a)
-rtsopts - b)
-prof - c)
-S - d)
-T
- a)
- To generate a detailed performance profile with time and space usage in GHC, which flag is used?
- a)
-fprof-auto - b)
-prof -fprof-cafs - c)
-Wall - d)
-fno-strictness
- a)
Understanding and Minimizing Space Leaks
- What is a space leak in Haskell?
- a) Unused memory that is not released
- b) A memory error that crashes the program
- c) The allocation of too many threads
- d) A function that takes too long to compute
- Which of the following is a common cause of space leaks in Haskell?
- a) Lazy evaluation of large data structures
- b) Using strict evaluation in all functions
- c) Avoiding recursion
- d) Using higher-order functions
- In Haskell, which operator can help force evaluation to avoid space leaks?
- a)
!(strictness annotation) - b)
seq - c)
++(list concatenation) - d)
foldr
- a)
- How can you detect space leaks in Haskell?
- a) By profiling the program with GHC
- b) By writing unit tests
- c) By avoiding the use of the
IOmonad - d) By using lazy evaluation in all functions
- Which of the following is an example of a space leak in Haskell?
- a) Using a large list without consuming it
- b) Using tail recursion properly
- c) Using strict evaluation in a function
- d) Performing computations in constant space
Using Strictness Annotations and seq
- What does the strictness annotation (
!) do in Haskell?
- a) Forces a function to evaluate its argument immediately
- b) Forces a function to be lazy in its evaluation
- c) Makes a function pure
- d) Specifies a function’s type
- Which of the following expressions is an example of strictness in Haskell?
- a)
f !x = x + 1 - b)
f x = x + 1 - c)
f x = x + (lazyComputation x) - d)
f !x = seq x (x + 1)
- What is the role of the
seqfunction in Haskell?
- a) Forces the evaluation of an argument before the function body
- b) Forces the evaluation of a whole list
- c) Introduces laziness in the program
- d) Composes functions sequentially
- Which of the following would help avoid space leaks in recursive functions?
- a) Using
seqto evaluate the result of each recursive call - b) Using
mapinstead offoldl - c) Avoiding lazy lists entirely
- d) Using
foldrfor tail-recursive functions
- In which scenario would you use the
seqfunction in Haskell?
- a) To evaluate an argument in a non-strict function before proceeding
- b) To handle errors in pure functions
- c) To implement lazy I/O operations
- d) To compose multiple monads together
Advanced Memory Management Techniques in GHC
- What does the
-fno-strictnessflag in GHC do?
- a) It disables strictness optimizations in the program
- b) It forces strict evaluation of all expressions
- c) It enables garbage collection
- d) It ensures tail call optimization
- How does GHC handle memory allocation for large data structures?
- a) By using a garbage collector
- b) By manually allocating memory using pointers
- c) By freezing the data structures
- d) By compressing the memory in the heap
- Which GHC flag helps enable better performance by controlling the garbage collector’s behavior?
- a)
+RTS -N - b)
-fno-strictness - c)
+RTS -s - d)
-fglasgow-exts
- What is the effect of the
-fexcess-precisionflag in GHC?
- a) It increases the precision of floating-point calculations
- b) It reduces the memory footprint of floating-point numbers
- c) It disables the garbage collector for better performance
- d) It forces the program to be executed strictly
- GHC uses a garbage collector to manage memory. Which type of garbage collection does it primarily use?
- a) Tracing garbage collection
- b) Reference counting
- c) Generational garbage collection
- d) Manual memory management
- Which technique can help reduce memory fragmentation in GHC?
- a) Using compact regions for memory allocation
- b) Using lazy evaluation
- c) Using more complex data structures
- d) Reusing heap memory dynamically
- When is the
+RTS -sflag useful in GHC?
- a) To print statistics about the program’s memory usage and garbage collection
- b) To optimize the execution time of the program
- c) To track strictness annotations
- d) To generate a runtime trace of function calls
- What is the purpose of using the
Compactmodule in GHC?
- a) To allocate memory more efficiently for large data structures
- b) To prevent memory leaks in recursive functions
- c) To track the state of all allocated memory
- d) To improve the garbage collector’s performance
- What does the
+RTS -G1flag do in GHC?
- a) Specifies the amount of memory allocated to the garbage collector
- b) Starts the program with a profiler enabled
- c) Increases the size of the heap for performance optimization
- d) Allows garbage collection in a single step
- Which GHC option allows for compiling Haskell code with optimizations for faster execution?
- a)
-O2 - b)
-fno-strictness - c)
-fno-liberate-case - d)
-fglasgow-exts
- The
-profoption in GHC is used for:
- a) Enabling performance profiling
- b) Profiling memory usage
- c) Running the program in a strict mode
- d) Tracking space leaks in recursive functions
- What is the benefit of using the
-threadedoption in GHC?
- a) It allows the program to run concurrently with multiple threads
- b) It reduces the memory overhead of the program
- c) It forces the program to use strict evaluation
- d) It enhances the garbage collector’s performance
- In GHC, which garbage collection technique is specifically suited for concurrent programs?
- a) Parallel garbage collection
- b) Tracing garbage collection
- c) Incremental garbage collection
- d) Reference counting
- How can you control the size of the heap in GHC for performance tuning?
- a) Using the
+RTS -Hflag - b) Using
seqto manage evaluation order - c) Using strictness annotations on all functions
- d) By applying a custom garbage collection strategy
- Which of the following is a major focus of GHC’s memory management strategy?
- a) Minimizing garbage collection pauses
- b) Avoiding multithreading
- c) Simplifying the type system
- d) Restricting the use of recursion
Answers
| Qno | Answer (Option with Text) |
|---|---|
| 1 | c) GHC’s built-in profiler |
| 2 | b) It generates a performance profile report |
| 3 | a) Function call counts and memory usage |
| 4 | b) -prof |
| 5 | b) -prof -fprof-cafs |
| 6 | a) Unused memory that is not released |
| 7 | a) Lazy evaluation of large data structures |
| 8 | b) seq |
| 9 | a) By profiling the program with GHC |
| 10 | a) Using a large list without consuming it |
| 11 | a) Forces a function to evaluate its argument immediately |
| 12 | a) f !x = x + 1 |
| 13 | a) Forces the evaluation of an argument before the function body |
| 14 | a) Using seq to evaluate the result of each recursive call |
| 15 | a) To evaluate an argument in a non-strict function before proceeding |
| 16 | a) It disables strictness optimizations in the program |
| 17 | a) By using a garbage collector |
| 18 | c) +RTS -s |
| 19 | a) It increases the precision of floating-point calculations |
| 20 | c) Generational garbage collection |
| 21 | a) Using compact regions for memory allocation |
| 22 | a) To print statistics about the program’s memory usage and garbage collection |
| 23 | a) To allocate memory more efficiently for large data structures |
| 24 | a) Specifies the amount of memory allocated to the garbage collector |
| 25 | a) -O2 |
| 26 | a) Enabling performance profiling |
| 27 | a) It allows the program to run concurrently with multiple threads |
| 28 | a) Parallel garbage collection |
| 29 | a) Using the +RTS -H flag |
| 30 | a) Minimizing garbage collection pauses |