On Mon, Dec 14, 2009 at 01:54:50PM +0100, Otto Moerbeek wrote:
> On Mon, Dec 14, 2009 at 07:44:31AM -0500, Ted Unangst wrote:
>
> > On Mon, Dec 14, 2009 at 3:58 AM, Otto Moerbeek <o...@drijf.net> wrote:
> > >> apart from the random page addresses obtained form mmap(2) malloc(3)
> > >> itself also randomizes cache en chunk operations. It uses a nibble of
> > >> randomness per call, so optimize that to not waste half the random
> > >> bits.
> > >>
> > >> Please test, should be a bit faster.
> >
> > I don't really like this. It looks complicated (hard to judge). arc4
> > is fast enough I don't think we need to worry about conserving bits,
> > and I'd be surprised if it actually were faster considering how much
> > work you're doing per nibble compared to the work to just run arc4.
> > However fast it may be, I feel much safer with the current code.
>
> Every call to arc4random_buf() causes a getpid() call, which is a
> syscall with all the overhead. This saves half of those.
Hit "send" too fast....
Yes, it is a bit more more complicated, but I think not too much.
-Otto
