Is kern.sched.preempt_thresh=0 a sensible default?

[Andriy Gapon]

On 08/06/2018 15:27, Gary Jennejohn wrote:
> On Thu, 7 Jun 2018 20:14:10 +0300
> Andriy Gapon <avg at FreeBSD.org> wrote:
> 
>> On 03/05/2018 12:41, Andriy Gapon wrote:
>>> I think that we need preemption policies that might not be expressible as one or
>>> two numbers.  A policy could be something like this:
>>> - interrupt threads can preempt only threads from "lower" classes: real-time,
>>> kernel, timeshare, idle;
>>> - interrupt threads cannot preempt other interrupt threads
>>> - real-time threads can preempt other real-time threads and threads from "lower"
>>> classes: kernel, timeshare, idle
>>> - kernel threads can preempt only threads from lower classes: timeshare, idle
>>> - interactive timeshare threads can only preempt batch and idle threads
>>> - batch threads can only preempt idle threads  
>>
>>
>> Here is a sketch of the idea: https://reviews.freebsd.org/D15693
>>
> 
> What about SCHED_4BSD?  Or is this just an example and you chose
> SCHED_ULE for it?

I haven't looked at SCHED_4BSD code at all.

-- 
Andriy Gapon