From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Graf <graf@amazon.com>
Cc: Joel Fernandes <joel@joelfernandes.org>,
vpillai <vpillai@digitalocean.com>,
Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
mingo@kernel.org, tglx@linutronix.de, pjt@google.com,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
Phil Auld <pauld@redhat.com>, Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
aubrey.li@linux.intel.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 00/13] Core scheduling v5
Date: Fri, 17 Apr 2020 15:08:25 +0200 [thread overview]
Message-ID: <20200417130825.GE20730@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <79529592-5d60-2a41-fbb6-4a5f8279f998@amazon.com>
On Fri, Apr 17, 2020 at 02:35:38PM +0200, Alexander Graf wrote:
> On 17.04.20 13:12, Peter Zijlstra wrote:
> If we first kick out the sibling HT for every #VMEXIT, performance will be
> abysmal, no?
I've been given to understand that people serious about virt try really
hard to avoid VMEXIT.
> > That doesn't completely solve things I think. Even if you run all
> > untrusted tasks as core exclusive, you still have a problem of them vs
> > interrupts on the other sibling.
> >
> > You need to somehow arrange all interrupts to the core happen on the
> > same sibling that runs your untrusted task, such that the VERW on
> > return-to-userspace works as intended.
> >
> > I suppose you can try and play funny games with interrupt routing tied
> > to the force-idle state, but I'm dreading what that'll look like. Or
> > were you going to handle this from your irq_enter() thing too?
>
> I'm not sure I follow. We have thread local interrupts (timers, IPIs) and
> device interrupts (network, block, etc).
>
> Thread local ones shouldn't transfer too much knowledge, so I'd be inclined
> to say we can just ignore that attack vector.
>
> Device interrupts we can easily route to HT0. If we now make "core
> exclusive" a synonym for "always run on HT0", we can guarantee that they
> always land on the same CPU, no?
>
> Then you don't need to hook into any idle state tracking, because you always
> know which CPU the "safe" one to both schedule tasks and route interrupts to
> is.
That would come apart most mighty when someone does an explicit
sched_setaffinity() for !HT0.
While that might work for some relatively contained systems like
chromeos, it will not work in general I think.
next prev parent reply other threads:[~2020-04-17 13:09 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 16:59 [RFC PATCH 00/13] Core scheduling v5 vpillai
2020-03-04 16:59 ` [RFC PATCH 01/13] sched: Wrap rq::lock access vpillai
2020-03-04 16:59 ` [RFC PATCH 02/13] sched: Introduce sched_class::pick_task() vpillai
2020-03-04 16:59 ` [RFC PATCH 03/13] sched: Core-wide rq->lock vpillai
2020-04-01 11:42 ` [PATCH] sched/arm64: store cpu topology before notify_cpu_starting Cheng Jian
2020-04-01 13:23 ` Valentin Schneider
2020-04-06 8:00 ` chengjian (D)
2020-04-09 9:59 ` Sudeep Holla
2020-04-09 10:32 ` Valentin Schneider
2020-04-09 11:08 ` Sudeep Holla
2020-04-09 17:54 ` Joel Fernandes
2020-04-10 13:49 ` chengjian (D)
2020-04-14 11:36 ` [RFC PATCH 03/13] sched: Core-wide rq->lock Peter Zijlstra
2020-04-14 21:35 ` Vineeth Remanan Pillai
2020-04-15 10:55 ` Peter Zijlstra
2020-04-14 14:32 ` Peter Zijlstra
2020-03-04 16:59 ` [RFC PATCH 04/13] sched/fair: Add a few assertions vpillai
2020-03-04 16:59 ` [RFC PATCH 05/13] sched: Basic tracking of matching tasks vpillai
2020-03-04 16:59 ` [RFC PATCH 06/13] sched: Update core scheduler queue when taking cpu online/offline vpillai
2020-03-04 16:59 ` [RFC PATCH 07/13] sched: Add core wide task selection and scheduling vpillai
2020-04-14 13:35 ` Peter Zijlstra
2020-04-16 23:32 ` Tim Chen
2020-04-17 10:57 ` Peter Zijlstra
2020-04-16 3:39 ` Chen Yu
2020-04-16 19:59 ` Vineeth Remanan Pillai
2020-04-17 11:18 ` Peter Zijlstra
2020-04-19 15:31 ` Chen Yu
2020-05-21 23:14 ` Joel Fernandes
2020-05-21 23:16 ` Joel Fernandes
2020-05-22 2:35 ` Joel Fernandes
2020-05-22 3:44 ` Aaron Lu
2020-05-22 20:13 ` Joel Fernandes
2020-03-04 16:59 ` [RFC PATCH 08/13] sched/fair: wrapper for cfs_rq->min_vruntime vpillai
2020-03-04 16:59 ` [RFC PATCH 09/13] sched/fair: core wide vruntime comparison vpillai
2020-04-14 13:56 ` Peter Zijlstra
2020-04-15 3:34 ` Aaron Lu
2020-04-15 4:07 ` Aaron Lu
2020-04-15 21:24 ` Vineeth Remanan Pillai
2020-04-17 9:40 ` Aaron Lu
2020-04-20 8:07 ` [PATCH updated] sched/fair: core wide cfs task priority comparison Aaron Lu
2020-04-20 22:26 ` Vineeth Remanan Pillai
2020-04-21 2:51 ` Aaron Lu
2020-04-24 14:24 ` [PATCH updated v2] " Aaron Lu
2020-05-06 14:35 ` Peter Zijlstra
2020-05-08 8:44 ` Aaron Lu
2020-05-08 9:09 ` Peter Zijlstra
2020-05-08 12:34 ` Aaron Lu
2020-05-14 13:02 ` Peter Zijlstra
2020-05-14 22:51 ` Vineeth Remanan Pillai
2020-05-15 10:38 ` Peter Zijlstra
2020-05-15 10:43 ` Peter Zijlstra
2020-05-15 14:24 ` Vineeth Remanan Pillai
2020-05-16 3:42 ` Aaron Lu
2020-05-22 9:40 ` Aaron Lu
2020-06-08 1:41 ` Ning, Hongyu
2020-03-04 17:00 ` [RFC PATCH 10/13] sched: Trivial forced-newidle balancer vpillai
2020-03-04 17:00 ` [RFC PATCH 11/13] sched: migration changes for core scheduling vpillai
2020-06-12 13:21 ` Joel Fernandes
2020-06-12 21:32 ` Vineeth Remanan Pillai
2020-06-13 2:25 ` Joel Fernandes
2020-06-13 18:59 ` Vineeth Remanan Pillai
2020-06-15 2:05 ` Li, Aubrey
2020-03-04 17:00 ` [RFC PATCH 12/13] sched: cgroup tagging interface " vpillai
2020-06-26 15:06 ` Vineeth Remanan Pillai
2020-03-04 17:00 ` [RFC PATCH 13/13] sched: Debug bits vpillai
2020-03-04 17:36 ` [RFC PATCH 00/13] Core scheduling v5 Tim Chen
2020-03-04 17:42 ` Vineeth Remanan Pillai
2020-04-14 14:21 ` Peter Zijlstra
2020-04-15 16:32 ` Joel Fernandes
2020-04-17 11:12 ` Peter Zijlstra
2020-04-17 12:35 ` Alexander Graf
2020-04-17 13:08 ` Peter Zijlstra [this message]
2020-04-18 2:25 ` Joel Fernandes
2020-05-09 14:35 ` Dario Faggioli
[not found] ` <38805656-2e2f-222a-c083-692f4b113313@linux.intel.com>
2020-05-09 3:39 ` Ning, Hongyu
2020-05-14 20:51 ` FW: " Gruza, Agata
2020-05-10 23:46 ` [PATCH RFC] Add support for core-wide protection of IRQ and softirq Joel Fernandes (Google)
2020-05-11 13:49 ` Peter Zijlstra
2020-05-11 14:54 ` Joel Fernandes
2020-05-20 22:26 ` [PATCH RFC] sched: Add a per-thread core scheduling interface Joel Fernandes (Google)
2020-05-21 4:09 ` [PATCH RFC] sched: Add a per-thread core scheduling interface(Internet mail) benbjiang(蒋彪)
2020-05-21 13:49 ` Joel Fernandes
2020-05-21 8:51 ` [PATCH RFC] sched: Add a per-thread core scheduling interface Peter Zijlstra
2020-05-21 13:47 ` Joel Fernandes
2020-05-21 20:20 ` Vineeth Remanan Pillai
2020-05-22 12:59 ` Peter Zijlstra
2020-05-22 21:35 ` Joel Fernandes
2020-05-24 14:00 ` Phil Auld
2020-05-28 14:51 ` Joel Fernandes
2020-05-28 17:01 ` Peter Zijlstra
2020-05-28 18:17 ` Phil Auld
2020-05-28 18:34 ` Phil Auld
2020-05-28 18:23 ` Joel Fernandes
2020-05-21 18:31 ` Linus Torvalds
2020-05-21 20:40 ` Joel Fernandes
2020-05-21 21:58 ` Jesse Barnes
2020-05-22 16:33 ` Linus Torvalds
2020-05-20 22:37 ` [PATCH RFC v2] Add support for core-wide protection of IRQ and softirq Joel Fernandes (Google)
2020-05-20 22:48 ` [PATCH RFC] sched: Use sched-RCU in core-scheduling balancing logic Joel Fernandes (Google)
2020-05-21 22:52 ` Paul E. McKenney
2020-05-22 1:26 ` Joel Fernandes
2020-06-25 20:12 ` [RFC PATCH 00/13] Core scheduling v5 Vineeth Remanan Pillai
2020-06-26 1:47 ` Joel Fernandes
2020-06-26 14:36 ` Vineeth Remanan Pillai
2020-06-26 15:10 ` Joel Fernandes
2020-06-26 15:12 ` Joel Fernandes
2020-06-27 16:21 ` Joel Fernandes
2020-06-30 14:11 ` Phil Auld
2020-06-29 12:33 ` Li, Aubrey
2020-06-29 19:41 ` Vineeth Remanan Pillai
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