Re: cprng_fast implementation benchmarks

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

Thor Lancelot Simon <tls%panix.com@localhost> wrote:
>RESULTS
> 
> kernel        cpb (32 bit)    4GB (1 way)     16GB (4 ways)   Scaling Factor
> ------        ------------    -----------     -------------   --------------
> arc4-mtx      35              42.58           398.83          0.106
> arc4-nomtx    24              42.12           2338.92         0.018
> arc4-percpu   27              33.63           41.59           0.808
> hc128-percpu  21              23.75           34.90           0.680
> hc128-inline  19              22.66           31.75           0.713
> chacha8       22              20.51           30.45           0.662
> chacha12      24              24.87           34.32           0.724
> chacha20      28              30.45           39.28           0.775

Looks good!

You mentioned that 4GB of data are generated by requesting 256 bytes.
It would be more interesting to see the throughput of 4 byte requests
i.e. how many cprng_fast32() calls per second can we do?

My vote would go to a cipher of Salsa20 family.  They undergone quite
more cryptoanalysis than HC-128.

-- 
Mindaugas