Re: upreempt_pri

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

> Hi,
> 
> I would like to change upreempt_pri to default to 0 as this makes 
> wakeups where the interrupted cpu schedules a thread on another cpu 
> behave like as if it where scheduled on the interrupted cpu.
> 
> For the case that  the to be scheduled on cpu is the interrupted one, 
> the behavior is like having upreempt_pri set to 0, as rescheduling 
> happens on return too usermode while in the cross cpu case this might be 
> delayed until the next timer interrupt.
> 
> This change makes some sluggishness regarding X to go a way.
> (Solaris defaults to 0 here as well, I think the only reason to set it 
> higher is on very big SMP machines where throughput is more important 
> then latency)
> 
> Lars

i'm not sure how it can make much differences given that l_kpribase is
normally PRI_KERNEL.

can you explain a little more?
or, even better, can you try to create a smaller test program to
demonstrate the sluggishness?

YAMAMOTO Takashi