Re: random(4) changes

Andi Kleen
2016-04-25T17:38:35Z

On Mon, Apr 25, 2016 at 07:25:55PM +0200, Stephan Mueller wrote:
> Am Montag, 25. April 2016, 09:06:03 schrieb Andi Kleen:
>
> Hi Andi,
>
> > Sandy Harris <sandyinchina@gmail.com> writes:
> >
> > There is also the third problem of horrible scalability of /dev/random
> > output on larger systems, for which patches are getting ignored.
> >
> > https://lkml.org/lkml/2016/2/10/716
> >
> > Ignoring problems does not make them go away.
>
> I have seen your patches, but I am not fully sure I understand the root cause.
> is the noise source handling the issue or the random number generation the
> issue?

Noise source handling is fine, the problem is the global locking on the
entropy pools when generating random numbers.

> If it is the latter, can you explain where the scalability issue comes in?

A single pool which is locked/written to does not scale. Larger systems
need multiple pools

-Andi

--
ak@linux.intel.com -- Speaking for myself only.