Why is one loop slower than 2 in C?

Re:Why is one loop slower than 2 in C? by kia on Sunday December 18, 2011 @11:54AM (#3366934)

In scientific computing it's not unusual to get 2x-3x speedups by doing simple optimizations like this one. For desktop applications it's nothing, but when your simulation is taking a week to complete then 2x-speedup is a huge improvement.

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Re:Why is one loop slower than 2 in C? by ahelwer on Sunday December 18, 2011 @01:09PM (#3367092)

This was especially the case on the old Pentium 4's. What we used to do was over-allocate the amount of memory needed, then offset the pointer into the allocated memory to avoid cache collisions.

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Re:Why is one loop slower than 2 in C? by dpe82 on Sunday December 18, 2011 @08:23PM (#3368066)

It's not always nothing, particularly when you're dealing with video. :)

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