Re:Don't use assembly unless you're an expert
by dankoss on Friday April 04, 2014 @10:25AM
(#7531569)
> Run speed is objective and measurable
Unfortunately in most modern OSes run speed on x86 is variable and profiling itself is intrusive. You might be able to get a general trendline toward a faster algorithm but it'll still be lost in statistical noise.
The second problem is that the underlying processor is a moving target. The x86 programming model doesn't directly map to hardware anymore, with out of order execution, branch predictors and register renaming. One variant of the processor with a particular caching algorithm might have totally different results than the next.
Unfortunately in most modern OSes run speed on x86 is variable and profiling itself is intrusive. You might be able to get a general trendline toward a faster algorithm but it'll still be lost in statistical noise.
The second problem is that the underlying processor is a moving target. The x86 programming model doesn't directly map to hardware anymore, with out of order execution, branch predictors and register renaming. One variant of the processor with a particular caching algorithm might have totally different results than the next.