Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-30 Thread Vincent Guittot
On Fri, 30 Oct 2020 at 03:11, Rik van Riel wrote: > > On Mon, 2020-10-26 at 17:52 +0100, Vincent Guittot wrote: > > On Mon, 26 Oct 2020 at 17:48, Chris Mason wrote: > > > On 26 Oct 2020, at 12:20, Vincent Guittot wrote: > > > > > > > what you are suggesting is something like: > > > > diff --git

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-29 Thread Rik van Riel
On Mon, 2020-10-26 at 17:52 +0100, Vincent Guittot wrote: > On Mon, 26 Oct 2020 at 17:48, Chris Mason wrote: > > On 26 Oct 2020, at 12:20, Vincent Guittot wrote: > > > > > what you are suggesting is something like: > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > index

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
On Mon, 26 Oct 2020 at 17:48, Chris Mason wrote: > > On 26 Oct 2020, at 12:20, Vincent Guittot wrote: > > > Le lundi 26 oct. 2020 à 12:04:45 (-0400), Rik van Riel a écrit : > >> On Mon, 26 Oct 2020 16:42:14 +0100 > >> Vincent Guittot wrote: > >>> On Mon, 26 Oct 2020 at 16:04, Rik van Riel

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Chris Mason
On 26 Oct 2020, at 12:20, Vincent Guittot wrote: Le lundi 26 oct. 2020 à 12:04:45 (-0400), Rik van Riel a écrit : On Mon, 26 Oct 2020 16:42:14 +0100 Vincent Guittot wrote: On Mon, 26 Oct 2020 at 16:04, Rik van Riel wrote: Could utilization estimates be off, either lagging or simply

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
Le lundi 26 oct. 2020 à 12:04:45 (-0400), Rik van Riel a écrit : > On Mon, 26 Oct 2020 16:42:14 +0100 > Vincent Guittot wrote: > > On Mon, 26 Oct 2020 at 16:04, Rik van Riel wrote: > > > > Could utilization estimates be off, either lagging or > > > simply having a wrong estimate for a task,

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Rik van Riel
On Mon, 26 Oct 2020 16:42:14 +0100 Vincent Guittot wrote: > On Mon, 26 Oct 2020 at 16:04, Rik van Riel wrote: > > Could utilization estimates be off, either lagging or > > simply having a wrong estimate for a task, resulting > > in no task getting pulled sometimes, while doing a > >

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
On Mon, 26 Oct 2020 at 16:42, Vincent Guittot wrote: > > On Mon, 26 Oct 2020 at 16:04, Rik van Riel wrote: > > > > On Mon, 2020-10-26 at 15:56 +0100, Vincent Guittot wrote: > > > On Mon, 26 Oct 2020 at 15:38, Rik van Riel wrote: > > > > On Mon, 2020-10-26 at 15:24 +0100, Vincent Guittot wrote:

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
On Mon, 26 Oct 2020 at 16:04, Rik van Riel wrote: > > On Mon, 2020-10-26 at 15:56 +0100, Vincent Guittot wrote: > > On Mon, 26 Oct 2020 at 15:38, Rik van Riel wrote: > > > On Mon, 2020-10-26 at 15:24 +0100, Vincent Guittot wrote: > > > > Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Chris Mason
On 26 Oct 2020, at 11:05, Chris Mason wrote: On 26 Oct 2020, at 10:24, Vincent Guittot wrote: Could you try the fix below ? --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9049,7 +9049,8 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s *

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
Le lundi 26 oct. 2020 à 11:05:35 (-0400), Chris Mason a écrit : > > > On 26 Oct 2020, at 10:24, Vincent Guittot wrote: > > > Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : > > > On 26 Oct 2020, at 4:39, Vincent Guittot wrote: > > > > > > > Hi Chris > > > > > > > > On Sat, 24

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Chris Mason
On 26 Oct 2020, at 10:24, Vincent Guittot wrote: Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : On 26 Oct 2020, at 4:39, Vincent Guittot wrote: Hi Chris On Sat, 24 Oct 2020 at 01:49, Chris Mason wrote: Hi everyone, We’re validating a new kernel in the fleet, and

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Rik van Riel
On Mon, 2020-10-26 at 15:56 +0100, Vincent Guittot wrote: > On Mon, 26 Oct 2020 at 15:38, Rik van Riel wrote: > > On Mon, 2020-10-26 at 15:24 +0100, Vincent Guittot wrote: > > > Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : > > > > On 26 Oct 2020, at 4:39, Vincent Guittot wrote:

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
On Mon, 26 Oct 2020 at 15:38, Rik van Riel wrote: > > On Mon, 2020-10-26 at 15:24 +0100, Vincent Guittot wrote: > > Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : > > > On 26 Oct 2020, at 4:39, Vincent Guittot wrote: > > > > > > > Hi Chris > > > > > > > > On Sat, 24 Oct 2020 at

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Rik van Riel
On Mon, 2020-10-26 at 15:24 +0100, Vincent Guittot wrote: > Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : > > On 26 Oct 2020, at 4:39, Vincent Guittot wrote: > > > > > Hi Chris > > > > > > On Sat, 24 Oct 2020 at 01:49, Chris Mason wrote: > > > > Hi everyone, > > > > > > > >

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
Le lundi 26 oct. 2020 à 08:45:27 (-0400), Chris Mason a écrit : > On 26 Oct 2020, at 4:39, Vincent Guittot wrote: > > > Hi Chris > > > > On Sat, 24 Oct 2020 at 01:49, Chris Mason wrote: > > > > > > Hi everyone, > > > > > > We’re validating a new kernel in the fleet, and compared with v5.2, >

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Chris Mason
On 26 Oct 2020, at 4:39, Vincent Guittot wrote: Hi Chris On Sat, 24 Oct 2020 at 01:49, Chris Mason wrote: Hi everyone, We’re validating a new kernel in the fleet, and compared with v5.2, Which version are you using ? several improvements have been added since v5.5 and the rework of

Re: [PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-26 Thread Vincent Guittot
Hi Chris On Sat, 24 Oct 2020 at 01:49, Chris Mason wrote: > > Hi everyone, > > We’re validating a new kernel in the fleet, and compared with v5.2, Which version are you using ? several improvements have been added since v5.5 and the rework of load_balance > performance is ~2-3% lower for some

[PATCH] fix scheduler regression from "sched/fair: Rework load_balance()"

2020-10-23 Thread Chris Mason
Hi everyone, We’re validating a new kernel in the fleet, and compared with v5.2, performance is ~2-3% lower for some of our workloads. After some digging, Johannes found that our involuntary context switch rate was ~2x higher, and we were leaving a CPU idle a higher percentage of the time,