Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-06 Thread Joel Fernandes
Hi Vineeth, On Mon, Jul 06, 2020 at 10:38:27AM -0400, Vineeth Remanan Pillai wrote: > On Mon, Jul 6, 2020 at 10:09 AM Joel Fernandes wrote: > > > > > I am not sure if this can happen. If the other sibling sets core_pick, it > > > will be under the core wide lock and it should set the

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-06 Thread Vineeth Remanan Pillai
On Mon, Jul 6, 2020 at 10:09 AM Joel Fernandes wrote: > > > I am not sure if this can happen. If the other sibling sets core_pick, it > > will be under the core wide lock and it should set the core_sched_seq also > > before releasing the lock. So when this cpu tries, it would see the > >

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-06 Thread Joel Fernandes
On Fri, Jul 03, 2020 at 04:21:46PM -0400, Vineeth Remanan Pillai wrote: > On Wed, Jul 1, 2020 at 7:28 PM Joel Fernandes wrote: > > > > From: "Joel Fernandes (Google)" > > Subject: [PATCH] sched: Fix CPU hotplug causing crashes in task selection > > logic > > > > The selection logic does not run

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-05 Thread Tim Chen
On 7/2/20 5:57 AM, Joel Fernandes wrote: > On Wed, Jul 01, 2020 at 05:54:11PM -0700, Tim Chen wrote: >> >> >> On 7/1/20 4:28 PM, Joel Fernandes wrote: >>> On Tue, Jun 30, 2020 at 09:32:27PM +, Vineeth Remanan Pillai wrote: From: Peter Zijlstra Instead of only selecting a

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-03 Thread Vineeth Remanan Pillai
On Wed, Jul 1, 2020 at 7:28 PM Joel Fernandes wrote: > > From: "Joel Fernandes (Google)" > Subject: [PATCH] sched: Fix CPU hotplug causing crashes in task selection > logic > > The selection logic does not run correctly if the current CPU is not in the > cpu_smt_mask (which it is not because

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-02 Thread Joel Fernandes
On Thu, Jul 02, 2020 at 08:57:57AM -0400, Joel Fernandes wrote: [...] > > > unconstrained pick, then rq->core_pick is set. The next time task > > > selection > > > logic runs when stopper needs to switch to idle, the current CPU is not in > > > the smt_mask. This causes the previous ->core_pick

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-02 Thread Joel Fernandes
On Wed, Jul 01, 2020 at 05:54:11PM -0700, Tim Chen wrote: > > > On 7/1/20 4:28 PM, Joel Fernandes wrote: > > On Tue, Jun 30, 2020 at 09:32:27PM +, Vineeth Remanan Pillai wrote: > >> From: Peter Zijlstra > >> > >> Instead of only selecting a local task, select a task for all SMT > >>

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-01 Thread Tim Chen
On 7/1/20 4:28 PM, Joel Fernandes wrote: > On Tue, Jun 30, 2020 at 09:32:27PM +, Vineeth Remanan Pillai wrote: >> From: Peter Zijlstra >> >> Instead of only selecting a local task, select a task for all SMT >> siblings for every reschedule on the core (irrespective which logical >> CPU

Re: [RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-07-01 Thread Joel Fernandes
On Tue, Jun 30, 2020 at 09:32:27PM +, Vineeth Remanan Pillai wrote: > From: Peter Zijlstra > > Instead of only selecting a local task, select a task for all SMT > siblings for every reschedule on the core (irrespective which logical > CPU does the reschedule). > > There could be races in

[RFC PATCH 06/16] sched: Add core wide task selection and scheduling.

2020-06-30 Thread Vineeth Remanan Pillai
From: Peter Zijlstra Instead of only selecting a local task, select a task for all SMT siblings for every reschedule on the core (irrespective which logical CPU does the reschedule). There could be races in core scheduler where a CPU is trying to pick a task for its sibling in core scheduler,