On Tue, 2 Dec 2014 21:52:35 +0000 Christos Zoulas <[email protected]> wrote: > In article > <cabfrot-qtat-hvap5zk2dq6vwp1k6zhjakgtswbtbh1fyhh...@mail.gmail.com>, > bch <[email protected]> wrote: > >This just popped up on the console (during > >./pkgsrc/databases/mysql56-server build): > > > >(transcribing by hand): > >=============================== > >ny runs of 4 0s (386 > 384) > >cprng 24455 6096 42: failed statistical RNG test > >=============================== > > Aha! I know I was not the only one (I turned a DEBUG into DIAGNOSTIC) > so we can find out what's wrong...
The test target was only missed by a little bit (386 vs 384), so I'd assume that it was only due to the statistical nature of the tests and no serious RNG failure. I had seen such error messages last year; here is what I wrote about that: > Yes, and I've come to the conclusion that the errors are within the > limits to be expected by statistics. > > I've done the math for the "monobit" test (because it is just a > binomial distribution) and found that the probability to have less > than 9725 ones in 20000 bits is ~4.9e-5. This means that we can > expect an error rate (<9725 or >10275 ones) of about one in 10000. > Now I've added a counter for test invocations to the kernel. > Got 13 hits of the monobit test within 143491 calls. > (These 140k calls took a minute or two running my test program.) One could assume that the various RNG tests are designed to have a similar probability of expected failures. It would be good to know how often the RNG tests were invoked. best regards Matthias ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Dr. Karl Eugen Huthmacher Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender), Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, Prof. Dr. Sebastian M. Schmidt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------
