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My rule of thumb : never optimize your code, instead optimize your algorithm as much as you can. After you finish, you can profile your code to see where you ma

by 0xFFC 10y ago

My rule of thumb : never optimize your code, instead optimize your algorithm as much as you can. After you finish, you can profile your code to see where you made mistake.

hellofunk 10y ago
Perfect advice. Most bottlenecks are not because of coding details, but algorithmic or architectural concerns.
- wmu 10y ago
  Although it's good to know that cache misses or false sharing may degrade performance of your carefully designed program. :)
  - hellofunk 10y ago
    A good algorithm with poor cache performance will still be much faster than a poor algorithm with no cache misses.
kgabis 10y ago
It's hard to optimize your code if you made bad decisions about memory layout of your data structures in the past.
paulddraper 10y ago
Algorithm optimizations can be far less readable than other kinds. Matrix multiplication is super simple. Strassen is more complicated. Coppersmith–Winograd is brain bending (besides being slower on actual data and hardware). The rule of thumb is: you have a complexity budget and a performance budget. Know what they should be, and choose economically.