5 ms·
> Most compilers aim for reproducibility... I suppose that's what I was seeking to gain clarity on. The remark on execution speed is a bit confusing though, c
by metaphor 10y ago
> Most compilers aim for reproducibility...
I suppose that's what I was seeking to gain clarity on.
The remark on execution speed is a bit confusing though, considering most software applications do not operate in a strict cycle-accurate, real-time environment, which is further exacerbated by the caching schemes of modern processors.
From your perspective, given the same repeatable test input, what threshold qualifies an executable's speed as being different?
- CJefferson 10y agoIt's common for small changes in code, or even the alignment of code (moving it all up/down memory) to have surprising results in the performance of the resulting code, due to things like page alignment. Here is a random example (you can find lots of others): http://stackoverflow.com/questions/17896714/why-would-introducing-useless-mov-instructions-speed-up-a-tight-loop-in-x86-64-a
- metaphor 10y agoHmmm...perhaps a rephrasing of the question given this particular example. Which would you consider to be the surprising part: ~0.75% average execution speed slowdown, or on the order of tens of milliseconds slowdown? W.r.t. page alignment, thought you may find this to be an interesting counter example[1]. [1] http://danluu.com/3c-conflict/ http://danluu.com/3c-conflict/