Re: Bull Mountain (IvyBridge +) random number generator

 schrieb Konstantin Belousov am 12.10.2012 18:48 (localtime):
> On Fri, Oct 12, 2012 at 10:50:55AM +0200, Harald Schmalzbauer wrote:
>> ...
> Try the stable/9 instead. The code was merged in r240950.
> There was a bug in the original patch with the similar description.

Thanks, it seems to be working with r240950 for RELENG_9_1
(ftp://ftp.omnilan.de/pub/FreeBSD/OmniLAN/deploy-tools/local-patches/RELENG_9_1/from_9-stable_branch/bull_mountain.patch).

dd if=/dev/random bs=1k count=1000 | ent
1000+0 records in
1000+0 records out
1024000 bytes transferred in 0.028026 secs (36537676 bytes/sec)
Entropy = 7.999827 bits per byte.

Optimum compression would reduce the size
of this 1024000 byte file by 0 percent.

Chi square distribution for 1024000 samples is 244.91, and randomly
would exceed this value 66.40 percent of the times.

Arithmetic mean value of data bytes is 127.6039 (127.5 = random).
Monte Carlo value for Pi is 3.139277888 (error 0.07 percent).
Serial correlation coefficient is -0.001852 (totally uncorrelated = 0.0).



I don't know if the requested verbose-boot-log is also of interest with
ESXi-Guest, in case I've attached it.

I think the man page answers my question how to find out (without
verbose_boot) what real rng is used for /dev/random.
If sysctl kern.random.sys is present, then it's sw rng, otherwise it's
hw-rng.
But random(4) needs to be uptdated:
    The only hardware implementation currently is for the
     VIA C3 Nehemiah (stepping 3 or greater) CPU.  More will be added in the
     future

Also, long time ago we had support for i815 RNG. Back in December 2005,
Mark Murray planned to re-implement it...
Does anybod know if the chipset RNG was still available in decent hw?

Here's the throughput difference for bull mountain (in ESXi 5.1 guest):
 
With options RDRAND_RNG:
dd if=/dev/random of=/dev/null bs=1k count=100000
100000+0 records in
100000+0 records out
102400000 bytes transferred in 0.722204 secs (141788199 bytes/sec)

Without:
dd if=/dev/random of=/dev/null bs=1k count=100000
100000+0 records in
100000+0 records out
102400000 bytes transferred in 1.054229 secs (97132594 bytes/sec)


Thanks,

-Harry