Re: Drawing the line between speed and simplicity/elegance

[Enrico Colombini <erix@...>]

On 10-May-15 02:53, Sean Conner wrote:
>    Just on a lark, I wrote two programs, one in pure Lua; the other one pure
> C.  The programs calculate the Mandelbrot set (but don't output anything---I
> wanted just the pure calculations) [2].  Here are some timings:
>
> 	Lua in PUC-Lua:	52.7s
> 	C:               2.7s (compiled with -O3)
> 	Lua in LuaJIT:   2.5s

Sean, out of curiosity, did you also measure with -Os?

I am asking this because, in a different context (a small 
microcontroller) I saw code emitted with -O3 that was slower than using 
-Os, despite 's' meaning 'size' and not 'speed'. It did strange things, 
such as jumping to a common piece of code (and back) from the middle of 
the part I was trying to optimize.

(disclaimer: I did not check if the code in its entirety was actually 
faster, because I was interested in squeezing the last clock cycle out 
of a particular section)

--
  Enrico