Re: [RFC PATCH v3 00/16] Core scheduling v3

[Aaron Lu]

On Thu, Aug 08, 2019 at 02:42:57PM -0700, Tim Chen wrote:
> On 8/8/19 10:27 AM, Tim Chen wrote:
> > On 8/7/19 11:47 PM, Aaron Lu wrote:
> >> On Tue, Aug 06, 2019 at 02:19:57PM -0700, Tim Chen wrote:
> >>> +void account_core_idletime(struct task_struct *p, u64 exec)
> >>> +{
> >>> +	const struct cpumask *smt_mask;
> >>> +	struct rq *rq;
> >>> +	bool force_idle, refill;
> >>> +	int i, cpu;
> >>> +
> >>> +	rq = task_rq(p);
> >>> +	if (!sched_core_enabled(rq) || !p->core_cookie)
> >>> +		return;
> >>
> >> I don't see why return here for untagged task. Untagged task can also
> >> preempt tagged task and force a CPU thread enter idle state.
> >> Untagged is just another tag to me, unless we want to allow untagged
> >> task to coschedule with a tagged task.
> > 
> > You are right.  This needs to be fixed.
> > 
> 
> Here's the updated patchset, including Aaron's fix and also
> added accounting of force idle time by deadline and rt tasks.

I have two other small changes that I think are worth sending out.

The first simplify logic in pick_task() and the 2nd avoid task pick all
over again when max is preempted. I also refined the previous hack patch to
make schedule always happen only for root cfs rq. Please see below for
details, thanks.

patch1: