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#1 2013-06-10 15:35:46

aardwolf
Member
From: Belgium
Registered: 2005-07-23
Posts: 256

/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 smile

(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)

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#2 2013-06-10 21:20:08

dimich
Member
From: Kharkiv, Ukraine
Registered: 2009-11-03
Posts: 35

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.

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#3 2013-06-10 21:26:08

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

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)

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#4 2013-06-10 22:21:03

graysky
Member
From: The worse toilet in Scotland
Registered: 2008-12-01
Posts: 8,820
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

CPU-optimized Linux-ck packages @ Repo-ck  • AUR packagesZsh and other configs

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