~/talk

C++ Performance and Optimisation

Talkat NDC TechTown 2017 · 2017-10-17..10-20· [c-and-cpp]
links:none on file
slides:none on file

Argues that optimization is a measured process: profile to remove obvious waste, then eliminate hot mallocs and temporaries, then choose algorithms and data layout. Shows examples: a telephony case with 130 mallocs per request that collapse when memory is preallocated, 10 million push_backs drop to one allocation with reserve, CPU vectorization yielding about vectorization 2.5x speedup, and dense storage beating pointer structures by a factor of 7–8 between dense and pointer-based; move semantics and unique_ptr remove copies and allocation overhead.

AI-written summary · about

  1. 0:00C++ performance myths
  2. 2:18Performance as a process
  3. 4:24Eliminating waste
  4. 6:55Real algorithms after cleanup
  5. 9:03Modern CPU complexity
  6. 13:00Memory bandwidth and cache
  7. 16:35Algorithm complexity and small numbers
  8. 17:57Data layout and cache-friendly
  9. 22:28Move semantics and C++11
  10. 26:02Memory allocation costs
  11. 28:08Container choice and bandwidth
  12. 30:13Hashing and comparison optimizations
  13. 32:49Domain knowledge and profiles
  14. 33:10Key access patterns
  15. 36:45Read/write ratios and cache coherence
  16. 38:52Working set size and cache fit
  17. 40:58Summary and process
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