Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 4 December 2016 at 00:25, Matt Fleming wrote: > On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: >> During fork, the utilization of a task is init once the rq has been >> selected because the current utilization level of the rq is used to set >> the utilization

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 4 December 2016 at 00:25, Matt Fleming wrote: > On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: >> During fork, the utilization of a task is init once the rq has been >> selected because the current utilization level of the rq is used to set >> the utilization of the fork task. As the

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 02:46:10PM +, Morten Rasmussen wrote: > On Tue, Nov 29, 2016 at 12:42:43PM +0100, Peter Zijlstra wrote: > > On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct > > > > *p, struct

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 02:46:10PM +, Morten Rasmussen wrote: > On Tue, Nov 29, 2016 at 12:42:43PM +0100, Peter Zijlstra wrote: > > On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct > > > > *p, struct

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: > During fork, the utilization of a task is init once the rq has been > selected because the current utilization level of the rq is used to set > the utilization of the fork task. As the task's utilization is still > null at this step of the

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: > During fork, the utilization of a task is init once the rq has been > selected because the current utilization level of the rq is used to set > the utilization of the fork task. As the task's utilization is still > null at this step of the

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 29 November 2016 at 15:50, Morten Rasmussen wrote: > On Tue, Nov 29, 2016 at 02:04:27PM +0100, Vincent Guittot wrote: >> On 29 November 2016 at 11:57, Morten Rasmussen >> wrote: >> > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 29 November 2016 at 15:50, Morten Rasmussen wrote: > On Tue, Nov 29, 2016 at 02:04:27PM +0100, Vincent Guittot wrote: >> On 29 November 2016 at 11:57, Morten Rasmussen >> wrote: >> > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: >> >> @@ -5708,13 +5708,6 @@ static int

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 02:04:27PM +0100, Vincent Guittot wrote: > On 29 November 2016 at 11:57, Morten Rasmussen > wrote: > > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: > >> @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p,

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 02:04:27PM +0100, Vincent Guittot wrote: > On 29 November 2016 at 11:57, Morten Rasmussen > wrote: > > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: > >> @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, > >> struct sched_domain

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 12:42:43PM +0100, Peter Zijlstra wrote: > On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, > > > struct sched_domain *sd, int t > > > > > > avg_cost =

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 12:42:43PM +0100, Peter Zijlstra wrote: > On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, > > > struct sched_domain *sd, int t > > > > > > avg_cost =

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 29 November 2016 at 11:57, Morten Rasmussen wrote: > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: >> During fork, the utilization of a task is init once the rq has been >> selected because the current utilization level of the rq is used to set >>

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 29 November 2016 at 11:57, Morten Rasmussen wrote: > On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: >> During fork, the utilization of a task is init once the rq has been >> selected because the current utilization level of the rq is used to set >> the utilization of the fork

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 11:44:19AM +, Matt Fleming wrote: > On Tue, 29 Nov, at 12:42:43PM, Peter Zijlstra wrote: > > > > IIRC, and my pounding head really doesn't remember much, the comment > > reads like we need the large fudge factor because hackbench. That is, > > hackbench would like this

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 11:44:19AM +, Matt Fleming wrote: > On Tue, 29 Nov, at 12:42:43PM, Peter Zijlstra wrote: > > > > IIRC, and my pounding head really doesn't remember much, the comment > > reads like we need the large fudge factor because hackbench. That is, > > hackbench would like this

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, 29 Nov, at 12:42:43PM, Peter Zijlstra wrote: > > IIRC, and my pounding head really doesn't remember much, the comment > reads like we need the large fudge factor because hackbench. That is, > hackbench would like this test to go away, but others benchmarks will > tank. > > Now, if only I

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, 29 Nov, at 12:42:43PM, Peter Zijlstra wrote: > > IIRC, and my pounding head really doesn't remember much, the comment > reads like we need the large fudge factor because hackbench. That is, > hackbench would like this test to go away, but others benchmarks will > tank. > > Now, if only I

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, > > struct sched_domain *sd, int t > > > > avg_cost = this_sd->avg_scan_cost; > > > > - /* > > -* Due to large variance we need a large fuzz

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Tue, Nov 29, 2016 at 10:57:59AM +, Morten Rasmussen wrote: > > @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, > > struct sched_domain *sd, int t > > > > avg_cost = this_sd->avg_scan_cost; > > > > - /* > > -* Due to large variance we need a large fuzz

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: > During fork, the utilization of a task is init once the rq has been > selected because the current utilization level of the rq is used to set > the utilization of the fork task. As the task's utilization is still > null at this

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, Nov 25, 2016 at 04:34:32PM +0100, Vincent Guittot wrote: > During fork, the utilization of a task is init once the rq has been > selected because the current utilization level of the rq is used to set > the utilization of the fork task. As the task's utilization is still > null at this

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 28 November 2016 at 18:01, Matt Fleming wrote: > On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index aa47589..820a787 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On 28 November 2016 at 18:01, Matt Fleming wrote: > On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index aa47589..820a787 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -5463,13 +5463,19 @@

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index aa47589..820a787 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5463,13 +5463,19 @@ find_idlest_group(struct sched_domain *sd, struct > task_struct *p, >

Re: [PATCH 1/2 v2] sched: fix find_idlest_group for fork

On Fri, 25 Nov, at 04:34:32PM, Vincent Guittot wrote: > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index aa47589..820a787 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5463,13 +5463,19 @@ find_idlest_group(struct sched_domain *sd, struct > task_struct *p, >

[PATCH 1/2 v2] sched: fix find_idlest_group for fork

During fork, the utilization of a task is init once the rq has been selected because the current utilization level of the rq is used to set the utilization of the fork task. As the task's utilization is still null at this step of the fork sequence, it doesn't make sense to look for some spare

[PATCH 1/2 v2] sched: fix find_idlest_group for fork

During fork, the utilization of a task is init once the rq has been selected because the current utilization level of the rq is used to set the utilization of the fork task. As the task's utilization is still null at this step of the fork sequence, it doesn't make sense to look for some spare