Practice Test Geeks(CPP) C++ Programming Professional Certificate Practice Test
← All CPP Flashcard Decks

Performance Optimization & Profiling Flashcards

7 cards from real CPP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Performance Optimization & Profiling flashcards as text

  1. Which cache concept refers to the tendency of programs to access memory locations near recently accessed locations?

    Answer: Spatial locality

    Spatial locality means programs tend to access nearby memory addresses, which is why sequential array traversal is cache-friendly.

  2. What is the primary purpose of loop unrolling as an optimization technique?

    Answer: Decrease loop overhead and enable instruction-level parallelism

    Loop unrolling reduces loop control overhead (increment, compare, branch) and exposes more independent instructions for the CPU pipeline.

  3. Which C++ standard attribute hints to the compiler that a branch is expected to be taken frequently?

    Answer: [[likely]]

    [[likely]] (C++20) hints that the branch is expected to be taken, allowing the compiler to optimize code layout for that path.

  4. What does 'false sharing' mean in the context of multi-threaded performance?

    Answer: Threads access different variables that reside on the same cache line

    False sharing occurs when two threads modify different variables that happen to share a cache line, causing unnecessary cache invalidation traffic.

  5. Which profiling technique samples the program counter at regular intervals without modifying source code?

    Answer: Statistical (sampling) profiling

    Statistical profiling periodically samples the PC to estimate where time is spent, with minimal overhead compared to full instrumentation.

  6. What is the effect of declaring a frequently called small function as `inline`?

    Answer: Hints to the compiler to consider inlining, potentially eliminating call overhead

    `inline` is a hint to the compiler; modern compilers may inline regardless and may ignore the hint if the function is too large.

  7. Which data structure layout typically yields better cache performance for iteration: Array of Structures (AoS) or Structure of Arrays (SoA)?

    Answer: SoA, because iterating one field accesses a contiguous array

    SoA keeps each field in its own contiguous array, so iterating a single field has perfect spatial locality and no wasted cache line bandwidth.