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From: Tim Chen <tim.c.chen@linux.intel.com>
To: Vineeth Remanan Pillai <vpillai@digitalocean.com>
Cc: "Nishanth Aravamudan" <naravamudan@digitalocean.com>,
	"Julien Desfossez" <jdesfossez@digitalocean.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Paul Turner" <pjt@google.com>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Linux List Kernel Mailing" <linux-kernel@vger.kernel.org>,
	"Dario Faggioli" <dfaggioli@suse.com>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Greg Kerr" <kerrnel@google.com>, "Phil Auld" <pauld@redhat.com>,
	"Aaron Lu" <aaron.lwe@gmail.com>,
	"Aubrey Li" <aubrey.intel@gmail.com>,
	"Valentin Schneider" <valentin.schneider@arm.com>,
	"Mel Gorman" <mgorman@techsingularity.net>,
	"Pawan Gupta" <pawan.kumar.gupta@linux.intel.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [RFC PATCH v4 00/19] Core scheduling v4
Date: Wed, 5 Feb 2020 16:28:18 -0800	[thread overview]
Message-ID: <e322a252-f983-e3f3-f823-16d0c16b2867@linux.intel.com> (raw)
In-Reply-To: <CANaguZAz+mw1Oi8ecZt+JuCWbf=g5UvKrdSvAeM82Z1c+9oWAw@mail.gmail.com>

On 1/14/20 7:40 AM, Vineeth Remanan Pillai wrote:
> On Mon, Jan 13, 2020 at 8:12 PM Tim Chen <tim.c.chen@linux.intel.com> wrote:
> 
>> I also encountered kernel panic with the v4 code when taking cpu offline or online
>> when core scheduler is running.  I've refreshed the previous patch, along
>> with 3 other patches to fix problems related to CPU online/offline.
>>
>> As a side effect of the fix, each core can now operate in core-scheduling
>> mode or non core-scheduling mode, depending on how many online SMT threads it has.
>>
>> Vineet, are you guys planning to refresh v4 and update it to v5?  Aubrey posted
>> a port to the latest kernel earlier.
>>
> Thanks for the updated patch Tim.
> 
> We have been testing with v4 rebased on 5.4.8 as RC kernels had given us
> trouble in the past. v5 is due soon and we are planning to release v5 when
> 5.5 comes out. As of now, v5 has your crash fixes and Aubrey's changes
> related to load balancing. We are investigating a performance issue with
> high overcommit io intensive workload and also we are trying to see if
> we can add synchronization during VMEXITs so that a guest vm cannot run
> run alongside with host kernel. We also need to think about the userland
> interface for corescheduling in preparation for upstreaming work.
> 

Vineet,

Have you guys been able to make progress on the issues with I/O intensive workload?

Can you explain a bit further what the problem is?  
Is the VM doing lots of I/O, causing frequent VMEXITs?
And the the host thread doing the I/O cannot run along side with vcpu
thread, resulting in extra forced idle?  So you are trying not to put vcpu
on the same core with such host thread?

Tim


  parent reply	other threads:[~2020-02-06  0:28 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-30 18:33 [RFC PATCH v4 00/19] Core scheduling v4 Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 01/19] stop_machine: Fix stop_cpus_in_progress ordering Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 02/19] sched: Fix kerneldoc comment for ia64_set_curr_task Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 03/19] sched: Wrap rq::lock access Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 04/19] sched/{rt,deadline}: Fix set_next_task vs pick_next_task Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 05/19] sched: Add task_struct pointer to sched_class::set_curr_task Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 06/19] sched/fair: Export newidle_balance() Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 07/19] sched: Allow put_prev_task() to drop rq->lock Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 08/19] sched: Rework pick_next_task() slow-path Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 09/19] sched: Introduce sched_class::pick_task() Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 10/19] sched: Core-wide rq->lock Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 11/19] sched: Basic tracking of matching tasks Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 12/19] sched: A quick and dirty cgroup tagging interface Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 13/19] sched: Add core wide task selection and scheduling Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 14/19] sched/fair: Add a few assertions Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 15/19] sched: Trivial forced-newidle balancer Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 16/19] sched: Debug bits Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 17/19] sched/fair: wrapper for cfs_rq->min_vruntime Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 18/19] sched/fair: core wide vruntime comparison Vineeth Remanan Pillai
2019-10-30 18:33 ` [RFC PATCH v4 19/19] sched/fair : Wake up forced idle siblings if needed Vineeth Remanan Pillai
2019-10-31 11:42 ` [RFC PATCH v4 00/19] Core scheduling v4 Li, Aubrey
2019-11-01 11:33   ` Li, Aubrey
2019-11-08  3:20     ` Li, Aubrey
2019-10-31 18:42 ` Phil Auld
2019-11-01 14:03   ` Vineeth Remanan Pillai
2019-11-01 16:35     ` Greg Kerr
2019-11-01 18:07       ` Dario Faggioli
2019-11-12  1:45     ` Dario Faggioli
2019-11-13 17:16       ` Tim Chen
2020-01-02  2:28       ` Aubrey Li
2020-01-10 23:19         ` Tim Chen
2019-11-11 19:10 ` Tim Chen
2020-01-14  1:12   ` Tim Chen
2020-01-14 15:40     ` Vineeth Remanan Pillai
2020-01-15  3:43       ` Li, Aubrey
2020-01-15 19:33         ` Tim Chen
2020-01-16  1:45           ` Aubrey Li
2020-01-17 16:00             ` Vineeth Remanan Pillai
2020-01-22 18:04               ` Gruza, Agata
2020-01-28  2:40       ` Dario Faggioli
     [not found]         ` <CANaguZDDpzrzdTmvjXvCmV2c+wBt6mXWSz4Vn-LJ-onc_Oj=yw@mail.gmail.com>
2020-02-01 15:31           ` Dario Faggioli
2020-02-06  0:28       ` Tim Chen [this message]
2020-02-06 22:37         ` Julien Desfossez
2020-02-12 23:07         ` Julien Desfossez
2020-02-13 18:37           ` Tim Chen
2020-02-14  6:10             ` Aubrey Li
     [not found]               ` <CANaguZC40mDHfL1H_9AA7H8cyd028t9PQVRqQ3kB4ha8R7hhqg@mail.gmail.com>
2020-02-15  6:01                 ` Aubrey Li
     [not found]                   ` <CANaguZBj_x_2+9KwbHCQScsmraC_mHdQB6uRqMTYMmvhBYfv2Q@mail.gmail.com>
2020-02-21 23:20                     ` Julien Desfossez
2020-03-17  0:55                       ` Joel Fernandes
2020-03-17 19:07                         ` Tim Chen
2020-03-17 20:18                           ` Tim Chen
2020-03-18  1:10                             ` Joel Fernandes
2020-03-17 21:17                           ` Thomas Gleixner
2020-03-17 21:58                             ` Tim Chen
2020-03-18  1:03                             ` Joel Fernandes
2020-03-18  2:30                               ` Joel Fernandes
2020-03-18  0:52                           ` Joel Fernandes
2020-03-18 11:53                             ` Thomas Gleixner
2020-03-19  1:54                               ` Joel Fernandes
2020-02-25  3:44               ` Aaron Lu
2020-02-25  5:32                 ` Aubrey Li
2020-02-25  7:34                   ` Aaron Lu
2020-02-25 10:40                     ` Aubrey Li
2020-02-25 11:21                       ` Aaron Lu
2020-02-25 13:41                         ` Aubrey Li
     [not found]                 ` <CANaguZD205ccu1V_2W-QuMRrJA9SjJ5ng1do4NCdLy8NDKKrbA@mail.gmail.com>
2020-02-26  3:13                   ` Aaron Lu
2020-02-26  7:21                   ` Aubrey Li
     [not found]                     ` <CANaguZDQZg-Z6aNpeLcjQ-cGm3X8CQOkZ_hnJNUyqDRM=yVDFQ@mail.gmail.com>
2020-02-27  4:45                       ` Aubrey Li
2020-02-28 23:55                       ` Tim Chen
2020-03-03 14:59                         ` Li, Aubrey
2020-03-03 23:54                           ` Li, Aubrey
2020-03-05  4:33                             ` Aaron Lu
2020-03-05  6:10                               ` Li, Aubrey
2020-03-05  8:52                                 ` Aaron Lu
2020-02-27  2:04                   ` Aaron Lu
2020-02-27 14:10                     ` Phil Auld
2020-02-27 14:37                       ` Aubrey Li
2020-02-28  2:54                       ` Aaron Lu
2020-03-05 13:45                         ` Aubrey Li
2020-03-06  2:41                           ` Aaron Lu
2020-03-06 18:06                             ` Tim Chen
2020-03-06 18:33                               ` Phil Auld
2020-03-06 21:44                                 ` Tim Chen
2020-03-07  3:13                                   ` Aaron Lu

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