Extremely poor performance crunching random numbers under PIV-FC5

[Andy Green]

BankHacker wrote:

>     1.- Andy told me to make my own bankhacker_random_r() function and
> avoid glibc's (libc.so.6). I am going to work on it, but it is not
> easy, I think.

What I meant by this was to make an empty implementation of random_r() 
in a tiny dynamic lib.  In this way you isolate if the problems come 
from something glibc random_r() does, or if there is some terrible 
problem with dynamic libs for that processor/compiler/compile environment.

>     2.- Jakub told that "On PIV, atomic instructions are horribly
> expensive. Either you have preloaded some library that called
> pthread_create, or your CPU is unable to do the jump around lock
> prefix trick quickly." It sounds very interesting but I don´t know how
> to handle this ... any further explanation would be a great hint.
> Thanks!

I didn't really understand what Jakub was telling with this (it seems 
that the compiler would react to expecting needing threadsafety in an 
expensive way?) but as I understood it the random_r() test was intended 
to test around this case.

-Andy

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