freebsd stable - Apr 2018 - kern.sched.quantum: Creepy, sadistic scheduler

On 4/4/18 9:32 pm, George Mitchell wrote:
> On 04/04/18 06:39, Alban Hertroys wrote:
>> [...]
>> That said, SCHED_ULE (the default scheduler for quite a while now) was
designed with multi-CPU configurations in mind and there are claims that
SCHED_4BSD works better for single-CPU configurations. You may give that a try,
if you're not already on SCHED_4BSD.
>> [...]
> A small, disgruntled community of FreeBSD users who have never seen
> proof that SCHED_ULE is better than SCHED_4BSD in any environment
> continue to regularly recompile with SCHED_4BSD.  I dread the day when
> that becomes impossible, but at least it isn't here yet.      -- George
>
for a single CPU you really should compile a kernel with SMP turned 
off and 4BSD scheduler.

ULE is just trying too hard to do stuff you don't need.

Julian Elischer wrote:
> for a single CPU you really should compile a kernel with SMP turned off
> and 4BSD scheduler.
>
> ULE is just trying too hard to do stuff you don't need.
Julian,

if we agree on this, I am fine.
(This implies that SCHED_4BSD will *not* be retired for an indefinite time!)

I tested yesterday, and SCHED_4BSD doesn't show the annoying behaviour.
SMP seems to be no problem (and I need that), but PREEMPTION is 
definitely related to the problem (see my other message sent now).

P.