svn commit: r284959 - in head: . share/man/man4 share/man/man9 sys/conf sys/dev/glxsb sys/dev/hifn sys/dev/random sys/dev/rndtest sys/dev/safe sys/dev/syscons sys/dev/ubsec sys/dev/virtio/random sy...

[Mark R V Murray]

> On 23 Jul 2015, at 08:59, Jeff Roberson <jroberson at jroberson.net> wrote:
> 
>> 
>> OK - I?m sold! I?ll make a kernel option defaulting to off. :-)
> 
> There are other sources that occur less frequently than millions of times per-second that may still provide some usefull entropy while being less performance critical under normal conditions.

I’m sure there are, and I’m keen to discover more! I’m not exactly the worlds best kernel hacker, so I’ll be requesting help.

My own crappy benchmark is “make world” and for that, I notice very little. For Video at Ludicrous Speed(™), I’m well prepared to accept otherwise! For crypto purposes, UMA is brilliant, though (but that won’t stop me defaulting it to “compiled out”).

> For example, context switches, traps, etc.  I could also imagine wiring up a pmc counter to something like cache misses or branch mispredicts that would be more difficult to game, especially if the counter was cycled irregularly.

Help requested here, please! If you could point out suitable harvesting points, I’ll see if the numbers from them look good.

Thanks!

M
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Mark R V Murray