Arch Linux

aardwolf

Member

From: Belgium

Registered: 2005-07-23

Posts: 304

/dev/random on Ivy Bridge CPU

Hello,

I have a Sandy Bridge instead of an Ivy Bridge CPU. Ivy Bridge has a new instruction for true random number generation at 500 Mbit/s.

If I type cat /dev/random, it only shows a few lines of random characters, increasing a bit if I move the mouse.

I'm curious, if you own an Ivy Bridge CPU, does /dev/random make use of it and spit out lots of random data very fast?

So please do an experiment for me, if you are using Linux on an Ivy Bridge CPU: Please let me know how much output "cat /dev/random" gives for you

(Note: NOT /dev/urandom!!).

In other words I'm just curious if Linux makes use of that potential, or if it only uses mouse movement and networking and stuff.

Thanks.

Last edited by aardwolf (2013-06-10 15:43:50)

dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 242

Re: /dev/random on Ivy Bridge CPU

Do you have /dev/hw_random device node? If yes, you should use rng-tools to fill kernel entropy pool. See Documentation/hw_random.txt in kernel sources for more details.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: /dev/random on Ivy Bridge CPU

When I use rng-tools, and rngd.service is running, /dev/random is crazy.  But like you I get about five random lines if it is not running.

Edit: BTW, I don't have a /dev/hw_random or a /dev/hwrandom.

Last edited by WonderWoofy (2013-06-10 21:27:52)

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,597

Website

Re: /dev/random on Ivy Bridge CPU

i7-3770k.  The command spits out 5-6 characters every few seconds.

% cat /dev/random
О\^CvAe)K7lm[B͍%Dk䗧[)o2bv1˛\s⠻v[_-Q{IJ,zYՂ́nYV

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