From: "Jan Beulich" <JBeulich@suse.com>
To: Dario Faggioli <dario.faggioli@citrix.com>,
Wei Liu <wei.liu2@citrix.com>, Chong Li <lichong659@gmail.com>
Cc: Chong Li <chong.li@wustl.edu>, Sisu Xi <xisisu@gmail.com>,
george.dunlap@eu.citrix.com, xen-devel@lists.xen.org,
Meng Xu <mengxu@cis.upenn.edu>,
dgolomb@seas.upenn.edu
Subject: Re: [PATCH v6 for Xen 4.7 1/4] xen: enable per-VCPU parameter settings for RTDS scheduler
Date: Wed, 09 Mar 2016 09:38:23 -0700 [thread overview]
Message-ID: <56E05F8F02000078000DAF15@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1457539804.3102.425.camel@citrix.com>
>>> On 09.03.16 at 17:10, <dario.faggioli@citrix.com> wrote:
> On Tue, 2016-03-08 at 19:09 +0000, Wei Liu wrote:
>> On Sun, Mar 06, 2016 at 11:55:55AM -0600, Chong Li wrote:
>>
>> > + spin_lock_irqsave(&prv->lock, flags);
>> > + svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
>> > + svc->period = period;
>> > + svc->budget = budget;
>> > + spin_unlock_irqrestore(&prv->lock, flags);
>> > +
>> And this locking pattern seems sub-optimal. You might be able to move
>> the lock and unlock outside the while loop?
>>
> Yes, unless I'm missing something, that looks possible to me, and would
> save a lot of acquire/release ping pong on the lock.
Well, there are guest memory accesses (which may fault) in the
loop body. While this may work right now, I don't think doing so
is a good idea.
> And yet, I'm not sure doing (for large guests) batches of 64 iterations
> with (as of now) interrupts disabled.
This I'd be much less worried about as long as what's inside the
loop body was a reasonably short code sequence.
Jan
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next prev parent reply other threads:[~2016-03-09 16:38 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-06 17:55 [PATCH v6 for Xen 4.7 0/4] Enable per-VCPU parameter settings for RTDS scheduler Chong Li
2016-03-06 17:55 ` [PATCH v6 for Xen 4.7 1/4] xen: enable " Chong Li
2016-03-07 12:59 ` Jan Beulich
2016-03-07 16:28 ` Chong Li
2016-03-07 16:40 ` Jan Beulich
2016-03-07 17:53 ` Dario Faggioli
2016-03-07 22:16 ` Chong Li
2016-03-08 9:10 ` Jan Beulich
2016-03-08 10:34 ` Dario Faggioli
2016-03-08 11:47 ` Jan Beulich
2016-03-08 19:09 ` Wei Liu
2016-03-09 16:10 ` Dario Faggioli
2016-03-09 16:38 ` Jan Beulich [this message]
2016-03-13 17:05 ` Chong Li
2016-03-14 8:37 ` Jan Beulich
2016-03-14 9:10 ` Dario Faggioli
2016-03-14 9:15 ` Jan Beulich
2016-03-14 10:05 ` Dario Faggioli
2016-03-15 16:22 ` Chong Li
2016-03-15 16:41 ` Dario Faggioli
2016-03-15 17:22 ` Chong Li
2016-03-16 3:14 ` Meng Xu
2016-03-16 3:32 ` Chong Li
2016-03-16 3:43 ` Meng Xu
2016-03-16 8:23 ` Dario Faggioli
2016-03-16 14:37 ` Meng Xu
2016-03-16 14:46 ` Chong Li
2016-03-16 14:53 ` Dario Faggioli
2016-03-16 14:46 ` Chong Li
2016-03-16 14:54 ` Dario Faggioli
2016-03-16 10:48 ` Jan Beulich
2016-03-10 22:35 ` Chong Li
2016-03-10 22:50 ` Wei Liu
2016-03-14 9:07 ` Dario Faggioli
2016-03-06 17:55 ` [PATCH v6 for Xen 4.7 2/4] libxc: " Chong Li
2016-03-08 19:09 ` Wei Liu
2016-03-08 19:32 ` Chong Li
2016-03-08 19:36 ` Wei Liu
2016-03-06 17:55 ` [PATCH v6 for Xen 4.7 3/4] libxl: " Chong Li
2016-03-08 19:12 ` Wei Liu
2016-03-09 0:38 ` Chong Li
2016-03-09 14:01 ` Wei Liu
2016-03-09 17:28 ` Dario Faggioli
2016-03-09 21:57 ` Chong Li
2016-03-09 17:09 ` Dario Faggioli
2016-03-09 17:28 ` Dario Faggioli
2016-03-06 17:55 ` [PATCH v6 for Xen 4.7 4/4] xl: " Chong Li
2016-03-08 19:12 ` Wei Liu
2016-03-08 21:24 ` Chong Li
2016-03-09 14:01 ` Wei Liu
2016-03-09 14:09 ` Wei Liu
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