locks and kernel randomness...

[Harrison Grundy]

On 02/25/15 02:05, Konstantin Belousov wrote:
> On Wed, Feb 25, 2015 at 01:47:55AM -0800, Harrison Grundy wrote:
>> Three choices here are attached here:
>> 
>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197922
>> 
>> The only remaining one I don't have a patch for is putting a
>> "real" PRNG in ULE.
>> 
>> At this point, as far as ULE goes, It just comes down to picking
>> from one of those approaches.
> 
> The third patch, ' Creates sched_random, using the system used in
> cpu_search.', seems to miss updating the dpcpu randomval in
> sched_random(), isn't it ?
> 

It does exactly what cpu_search does.

I really think the scheduler does not actually need randomness in
these locations. I've been running for the past few days on a few
systems here that way for testing purposes without issue.

I'll post a separate call for testers for a patch that overtly removes
them. ULE has a ton of different methods for balancing load between
cores (which is why you can turn off the long term balancer entirely).

--- Harrison