News for hackers. Stuff that matters.

A comment on RDRAND on AMD Ryzen 9 5900X is flakey. Parent comment

Re:RDRAND on AMD Ryzen 9 5900X is flakey by floatboth on Monday January 11, 2021 @05:15PM (#25738193)
It's literally just the birthday paradox. You get collisions very quickly for 32-bit numbers. This test finds collisions on Intel too.
[ Parent | on HN ]
Re:RDRAND on AMD Ryzen 9 5900X is flakey by edwintorok on Monday January 11, 2021 @06:23PM (#25739526)
A better test is to use dieharder, see here: https://github.com/systemd/systemd/issues/18184#issuecomment...
[ Parent | on HN ]
Re:RDRAND on AMD Ryzen 9 5900X is flakey by rurban on Tuesday January 12, 2021 @03:02PM (#25752645)
I tested it with dieharder here. It's atrocious without the BiOS patch.

https://rurban.github.io/dieharder/QUALITY.html

[ Parent | on HN ]
Re:RDRAND on AMD Ryzen 9 5900X is flakey by mzs on Friday January 15, 2021 @04:00PM (#25796393)
yep was a FW HW issue: https://github.com/systemd/systemd/issues/18184#event-420318...
[ Parent | on HN ]
Re:RDRAND on AMD Ryzen 9 5900X is flakey by mzs on Tuesday January 12, 2021 @12:14AM (#25742595)
That was before sort was used, but then the later tests were no longer sound.
[ Parent | on HN ]