Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Mel Gorman
On Fri, Dec 04, 2020 at 04:43:05PM +0100, Vincent Guittot wrote: > On Fri, 4 Dec 2020 at 16:40, Mel Gorman wrote: > > > > On Fri, Dec 04, 2020 at 04:23:48PM +0100, Vincent Guittot wrote: > > > On Fri, 4 Dec 2020 at 15:31, Mel Gorman > > > wrote: > > > > > > > > On Fri, Dec 04, 2020 at

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Fri, 4 Dec 2020 at 16:40, Mel Gorman wrote: > > On Fri, Dec 04, 2020 at 04:23:48PM +0100, Vincent Guittot wrote: > > On Fri, 4 Dec 2020 at 15:31, Mel Gorman wrote: > > > > > > On Fri, Dec 04, 2020 at 02:47:48PM +0100, Vincent Guittot wrote: > > > > > IIUC, select_idle_core and select_idle_cpu

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Mel Gorman
On Fri, Dec 04, 2020 at 04:23:48PM +0100, Vincent Guittot wrote: > On Fri, 4 Dec 2020 at 15:31, Mel Gorman wrote: > > > > On Fri, Dec 04, 2020 at 02:47:48PM +0100, Vincent Guittot wrote: > > > > IIUC, select_idle_core and select_idle_cpu share the same > > > > cpumask(select_idle_mask)? > > > >

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Fri, 4 Dec 2020 at 15:31, Mel Gorman wrote: > > On Fri, Dec 04, 2020 at 02:47:48PM +0100, Vincent Guittot wrote: > > > IIUC, select_idle_core and select_idle_cpu share the same > > > cpumask(select_idle_mask)? > > > If the target's sibling is removed from select_idle_mask from > > >

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Mel Gorman
On Fri, Dec 04, 2020 at 02:47:48PM +0100, Vincent Guittot wrote: > > IIUC, select_idle_core and select_idle_cpu share the same > > cpumask(select_idle_mask)? > > If the target's sibling is removed from select_idle_mask from > > select_idle_core(), > > select_idle_cpu() will lose the chance to

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Mel Gorman
On Fri, Dec 04, 2020 at 02:17:20PM +0100, Vincent Guittot wrote: > On Fri, 4 Dec 2020 at 14:13, Vincent Guittot > wrote: > > > > On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: > > > > > > On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: > > > > > The intent was that the sibling

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Li, Aubrey
On 2020/12/4 21:47, Vincent Guittot wrote: > On Fri, 4 Dec 2020 at 14:40, Li, Aubrey wrote: >> >> On 2020/12/4 21:17, Vincent Guittot wrote: >>> On Fri, 4 Dec 2020 at 14:13, Vincent Guittot >>> wrote: On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: > > On Fri, Dec 04,

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Fri, 4 Dec 2020 at 14:40, Li, Aubrey wrote: > > On 2020/12/4 21:17, Vincent Guittot wrote: > > On Fri, 4 Dec 2020 at 14:13, Vincent Guittot > > wrote: > >> > >> On Fri, 4 Dec 2020 at 12:30, Mel Gorman > >> wrote: > >>> > >>> On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote:

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Li, Aubrey
On 2020/12/4 21:40, Li, Aubrey wrote: > On 2020/12/4 21:17, Vincent Guittot wrote: >> On Fri, 4 Dec 2020 at 14:13, Vincent Guittot >> wrote: >>> >>> On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: >> The intent was

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Li, Aubrey
On 2020/12/4 21:17, Vincent Guittot wrote: > On Fri, 4 Dec 2020 at 14:13, Vincent Guittot > wrote: >> >> On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: >>> >>> On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: > The intent was that the sibling might still be an idle

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Fri, 4 Dec 2020 at 14:13, Vincent Guittot wrote: > > On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: > > > > On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: > > > > The intent was that the sibling might still be an idle candidate. In > > > > the current draft of the series, I

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Fri, 4 Dec 2020 at 12:30, Mel Gorman wrote: > > On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: > > > The intent was that the sibling might still be an idle candidate. In > > > the current draft of the series, I do not even clear this so that the > > > SMT sibling is

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Mel Gorman
On Fri, Dec 04, 2020 at 11:56:36AM +0100, Vincent Guittot wrote: > > The intent was that the sibling might still be an idle candidate. In > > the current draft of the series, I do not even clear this so that the > > SMT sibling is considered as an idle candidate. The reasoning is that if > > there

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-04 Thread Vincent Guittot
On Thu, 3 Dec 2020 at 18:52, Mel Gorman wrote: > > On Thu, Dec 03, 2020 at 05:38:03PM +0100, Vincent Guittot wrote: > > On Thu, 3 Dec 2020 at 15:11, Mel Gorman wrote: > > > > > > The target CPU is definitely not idle in both select_idle_core and > > > select_idle_cpu. For select_idle_core(), the

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-03 Thread Mel Gorman
On Thu, Dec 03, 2020 at 05:38:03PM +0100, Vincent Guittot wrote: > On Thu, 3 Dec 2020 at 15:11, Mel Gorman wrote: > > > > The target CPU is definitely not idle in both select_idle_core and > > select_idle_cpu. For select_idle_core(), the SMT is potentially > > checked unnecessarily as the core is

Re: [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-03 Thread Vincent Guittot
On Thu, 3 Dec 2020 at 15:11, Mel Gorman wrote: > > The target CPU is definitely not idle in both select_idle_core and > select_idle_cpu. For select_idle_core(), the SMT is potentially > checked unnecessarily as the core is definitely not idle if the > target is busy. For select_idle_cpu(), the

[PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched

2020-12-03 Thread Mel Gorman
The target CPU is definitely not idle in both select_idle_core and select_idle_cpu. For select_idle_core(), the SMT is potentially checked unnecessarily as the core is definitely not idle if the target is busy. For select_idle_cpu(), the first CPU checked is simply a waste. Signed-off-by: Mel