Re: Patch: cprng_fast performance - please review.

Thor Lancelot Simon <[email protected]> Fri, 18 Apr 2014 12:23:07 -0400
Newsgroups gmane.os.netbsd.devel.crypto,gmane.os.netbsd.devel.kernel
Message-ID <[email protected]>
On Fri, Apr 18, 2014 at 10:27:45PM +0900, Izumi Tsutsui wrote:
> 
> Note the caller of this hc128_init() is:
> 
> I'm afraid "9KB stack on rekeying" is fatal on most ports.

Well, the cipher should hardly ever get rekeyed.  The rekeying
intervals could be considerably larger; I did not want to
increase them too much compared to the old implementation.

We can kmem_alloc these structures instead.

> I wonder if we should also consider "speed vs memory"
> especially for embedded users.

It's 9K per CPU, total.  Seems OK, no?

Aside from reformatting, I left the HC-128 code itself
completely alone -- this is my preference for the core
crypto transforms -- but the changes you suggest seem
right to me.

Thor