Messages in this thread |  | | | Subject | Re: [PATCH] API for true Random Number Generators to add entropy (2.6.11) | | From | Evgeniy Polyakov <> | | Date | Tue, 29 Mar 2005 15:42:05 +0400 |
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On Tue, 2005-03-29 at 20:46 +1000, Herbert Xu wrote: > On Tue, Mar 29, 2005 at 02:50:28PM +0400, Evgeniy Polyakov wrote: > > > > Without ability speed this up in kernel, we completely [ok, almost] > > loose all RNG advantages. > > Well if you can demonstrate that you're getting a higher rate of > throughput from your RNG by doing this in kernel space vs. doing > it in user space please let me know.
Quote from VIA RNG crypto analysis:
"Bitrate. The RNG generates output at significantly higher rates than most PC-based randomness resources. Raw bits are produced at rates of 30 to 50 Mbits/sec, and whitened bits were observed at rates of 4 to 9 Mbits/sec. Variations in output rates depend on the RNG configuration and the oscillator rates. PRNGs seeded with the Nehemiah RNG should be able to easily sustain output in excess of 2 Mbits of entropy per second, which should eliminate blocked PRNG reads in virtually all applications."
While raw bits reading from hw_random on the fastest VIA boards can exceed 55mbits per second [above quite was taken from VIA C3 Nehemiah analysis], it is not evaluated in rngd and is not written back to the /dev/random.
David provided his patch exactly because of "Adding this can dramatically improve the performance of /dev/random on small embedded systems which do not generate much entropy." and it works.
-- Evgeniy Polyakov
Crash is better than data corruption -- Arthur Grabowski [unhandled content-type:application/pgp-signature] |  |