On Wed, Jul 30, 2014 at 10:30:08AM +0200, Peter Zijlstra wrote:
> >
> > Isn't the entire effort starting from PJT and Ben up to now to soften the
> > extremely
> > dynamic changes (runnable or not, weight change, etc)? Assume task does not
> > change
> > weight much, but group entity does as Pet
On Wed, Jul 30, 2014 at 06:27:52AM +0800, Yuyang Du wrote:
> On Tue, Jul 29, 2014 at 03:17:29PM +0200, Vincent Guittot wrote:
> > >>
> > >> IMHO, we should apply the same policy than the one i mentioned for
> > >> task. So the load_avg of an entity or a cfs_rq will not be disturbed
> > >> by an old
On Tue, Jul 29, 2014 at 03:35:10PM +0200, Peter Zijlstra wrote:
>
> Does not compute, sorry. How would delaying the effect of migrations
> help?
>
> Suppose we have 2 cpus and 6 tasks. cpu0 has 2 tasks, cpu1 has 4 tasks.
> the group weights are resp. 341 and 682. We compute we have an imbalance
>
On Tue, Jul 29, 2014 at 03:17:29PM +0200, Vincent Guittot wrote:
> >>
> >> IMHO, we should apply the same policy than the one i mentioned for
> >> task. So the load_avg of an entity or a cfs_rq will not be disturbed
> >> by an old but no more valid weight
> >>
> >
> > Well, I see your point. But th
On Tue, Jul 29, 2014 at 03:35:10PM +0200, Peter Zijlstra wrote:
> On Tue, Jul 29, 2014 at 09:53:44AM +0800, Yuyang Du wrote:
> > On Tue, Jul 29, 2014 at 11:39:11AM +0200, Peter Zijlstra wrote:
> > > > > For task, assuming its load.weight does not change much, yes, we can.
> > > > > But in theory,
On Tue, Jul 29, 2014 at 09:53:44AM +0800, Yuyang Du wrote:
> On Tue, Jul 29, 2014 at 11:39:11AM +0200, Peter Zijlstra wrote:
> > > > For task, assuming its load.weight does not change much, yes, we can.
> > > > But in theory, task's
> > >
> > > I would even say that the load_avg of a task should
On 29 July 2014 03:43, Yuyang Du wrote:
> On Tue, Jul 29, 2014 at 11:12:37AM +0200, Vincent Guittot wrote:
>> >>
>> >> Do you really need to have *w for computing the load_sum ? can't you
>> >> only use it when computing the load_avg ?
>> >>
>> >> sa->load_avg = div_u64(sa->load_sum * w , LOAD_AVG
On Tue, Jul 29, 2014 at 09:09:45AM +0800, Yuyang Du wrote:
> > > +#define subtract_until_zero(minuend, subtrahend) \
> > > + (subtrahend < minuend ? minuend - subtrahend : 0)
> >
> > WTH is a minuend or subtrahend? Are you a wordsmith in your spare time
> > and like to make up your own words?
> >
On Tue, Jul 29, 2014 at 08:56:41AM +0800, Yuyang Du wrote:
> On Mon, Jul 28, 2014 at 12:48:37PM +0200, Peter Zijlstra wrote:
> > > +static __always_inline u64 decay_load(u64 val, u64 n)
> > > +{
> > > + if (likely(val <= UINT_MAX))
> > > + val = decay_load32(val, n);
> > > + else {
> > > +
On Tue, Jul 29, 2014 at 11:39:11AM +0200, Peter Zijlstra wrote:
> > > For task, assuming its load.weight does not change much, yes, we can. But
> > > in theory, task's
> >
> > I would even say that the load_avg of a task should not be impacted by
> > an old priority value. Once, the priority of a
On Tue, Jul 29, 2014 at 11:12:37AM +0200, Vincent Guittot wrote:
> >>
> >> Do you really need to have *w for computing the load_sum ? can't you
> >> only use it when computing the load_avg ?
> >>
> >> sa->load_avg = div_u64(sa->load_sum * w , LOAD_AVG_MAX)
> >>
> >
> > For task, assuming its load.w
On Tue, Jul 29, 2014 at 11:12:37AM +0200, Vincent Guittot wrote:
> On 27 July 2014 19:36, Yuyang Du wrote:
> > Hi Vincent,
> >
> > On Fri, Jul 18, 2014 at 11:43:00AM +0200, Vincent Guittot wrote:
> >> > @@ -2291,23 +2299,24 @@ static __always_inline int
> >> > __update_entity_runnable_avg(u64 now
On Mon, Jul 28, 2014 at 07:19:09PM +0200, Peter Zijlstra wrote:
> > > And here we try and make good on that assumption. The thing I worry
> > > about is what happens if the machine is entirely idle...
> > >
> > > What guarantees an semi up-to-date cfs_rq->avg.last_update_time.
> >
> > update_block
On 27 July 2014 19:36, Yuyang Du wrote:
> Hi Vincent,
>
> On Fri, Jul 18, 2014 at 11:43:00AM +0200, Vincent Guittot wrote:
>> > @@ -2291,23 +2299,24 @@ static __always_inline int
>> > __update_entity_runnable_avg(u64 now,
>> > delta >>= 10;
>> > if (!delta)
>> > re
On Mon, Jul 28, 2014 at 01:39:39PM +0200, Peter Zijlstra wrote:
> > -static inline void __update_group_entity_contrib(struct sched_entity *se)
> > +static inline void update_tg_load_avg(struct cfs_rq *cfs_rq)
> > {
> > + long delta = cfs_rq->avg.load_avg - cfs_rq->tg_load_avg_contrib;
> >
> >
On Mon, Jul 28, 2014 at 12:48:37PM +0200, Peter Zijlstra wrote:
> > +static __always_inline u64 decay_load(u64 val, u64 n)
> > +{
> > + if (likely(val <= UINT_MAX))
> > + val = decay_load32(val, n);
> > + else {
> > + val *= (u32)decay_load32(1 << 15, n);
> > + val
On Mon, Jul 28, 2014 at 09:58:19AM -0700, bseg...@google.com wrote:
> Peter Zijlstra writes:
>
> >> @@ -4551,18 +4382,34 @@ migrate_task_rq_fair(struct task_struct *p, int
> >> next_cpu)
> >> {
> >>struct sched_entity *se = &p->se;
> >>struct cfs_rq *cfs_rq = cfs_rq_of(se);
> >> + u64
Peter Zijlstra writes:
>> @@ -4551,18 +4382,34 @@ migrate_task_rq_fair(struct task_struct *p, int
>> next_cpu)
>> {
>> struct sched_entity *se = &p->se;
>> struct cfs_rq *cfs_rq = cfs_rq_of(se);
>> +u64 last_update_time;
>>
>> /*
>> + * Task on old CPU catches up with i
> +static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
> {
> + int decayed;
>
> + if (atomic_long_read(&cfs_rq->removed_load_avg)) {
> + long r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
> + cfs_rq->avg.load_avg =
> subtract_until_ze
On Fri, Jul 18, 2014 at 07:26:06AM +0800, Yuyang Du wrote:
> -static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int
> force_update)
> +/* Add the load generated by se into cfs_rq's load average */
> +static inline void enqueue_entity_load_avg(struct sched_entity *se)
> {
> + struc
On Fri, Jul 18, 2014 at 07:26:06AM +0800, Yuyang Du wrote:
> -static inline void __update_tg_runnable_avg(struct sched_avg *sa,
> - struct cfs_rq *cfs_rq)
> -{
> - struct task_group *tg = cfs_rq->tg;
> - long contrib;
> -
> - /* The fractio
On Fri, Jul 18, 2014 at 07:26:06AM +0800, Yuyang Du wrote:
> @@ -665,20 +660,27 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct
> sched_entity *se)
> }
>
> #ifdef CONFIG_SMP
> -static unsigned long task_h_load(struct task_struct *p);
>
> -static inline void __update_task_entity_cont
Hi Vincent,
On Fri, Jul 18, 2014 at 11:43:00AM +0200, Vincent Guittot wrote:
> > @@ -2291,23 +2299,24 @@ static __always_inline int
> > __update_entity_runnable_avg(u64 now,
> > delta >>= 10;
> > if (!delta)
> > return 0;
> > - sa->last_runnable_update = now;
On 18 July 2014 01:26, Yuyang Du wrote:
> The idea of per entity runnable load average (let runnable time contribute to
> load
> weight) was proposed by Paul Turner, and it is still followed by this
> rewrite. This
> rewrite is done due to the following ends:
>
> 1. cfs_rq's load average (namely
The idea of per entity runnable load average (let runnable time contribute to
load
weight) was proposed by Paul Turner, and it is still followed by this rewrite.
This
rewrite is done due to the following ends:
1. cfs_rq's load average (namely runnable_load_avg and blocked_load_avg) is
updated
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