Python question - first call is slower?

[Nadav Har'El]

On Wed, Jun 20, 2012, Oleg Goldshmidt wrote about "Re: Python question - first call is slower?":
> I would - naively! - think that "stuff (not only, or necessarily, the
> python code stuff, but also what it needs from the system) would indeed be
> loaded dynamically when it is needed. I don't base this on anything I know,
> but on the intuitive notion that whatever Python does works as "normal C
> libraries" - it's implemented in C, right?

This is a good angle to investigate, although since I noticed the
function becomes uniformly slower (after 1/3rd of the code, it spends
1/3rd of 14 milliseconds), it would be strange that I am loading so many
shared libraries for this to be so uniform, but I guess anything is
possible.

> Another (kinda related) possibility - some cacheing going on?
> What happens if you run the program twice - is the first call slow every
> time or just the first time?

No, every time I run the program, the first call is slow and the
subsequent calls are fast. So it's not disk reads or anything which is
cached by the system between runs.

> In general, t does not surprise me that something - whatever - runs slower
> the first time than subsequent times - it happens often.

Yes, its sad that computer software has become so complex that often you
don't understand what your program *really* does, and you start to
accept annoying phenomenon as laws of nature :( In a few years, when
software is as complex as human brains, I guess it would be normal to
explain that some software is slower today because it is depressed ;-)

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Nadav Har'El                        |                 Wednesday, Jun 20 2012, 
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