From: Dario Faggioli <dario.faggioli@citrix.com>
To: Jan Beulich <JBeulich@suse.com>, Chong Li <lichong659@gmail.com>
Cc: Chong Li <chong.li@wustl.edu>, Wei Liu <wei.liu2@citrix.com>,
Sisu Xi <xisisu@gmail.com>,
GeorgeDunlap <george.dunlap@eu.citrix.com>,
xen-devel <xen-devel@lists.xen.org>,
Meng Xu <mengxu@cis.upenn.edu>,
Dagaen Golomb <dgolomb@seas.upenn.edu>
Subject: Re: [PATCH v6 for Xen 4.7 1/4] xen: enable per-VCPU parameter settings for RTDS scheduler
Date: Mon, 14 Mar 2016 11:05:30 +0100 [thread overview]
Message-ID: <1457949930.3102.641.camel@citrix.com> (raw)
In-Reply-To: <56E68F5202000078000DBF46@prv-mh.provo.novell.com>
[-- Attachment #1.1: Type: text/plain, Size: 1675 bytes --]
On Mon, 2016-03-14 at 03:15 -0600, Jan Beulich wrote:
> > > > On 14.03.16 at 10:10, <dario.faggioli@citrix.com> wrote:
> >
> > I think it has some value to have this in the logs. In fact,
> > someone
> > that ended up with small values --either by bug/chance, or in
> > general
> > without a specific need for them-- and is seeing
> > performance/scheduling
> > issues will still be able to find this.
> >
> > And printing it somewhere else than in Xen is impractical (see my
> > reply
> > to Wei).
> >
> > However, we may well print it just once, as soon as the first vcpu
> > with
> > potentially problematic parameters is hit, and then silence it.
> >
> > Linux has things like WARN_ON_ONCE to do this:
> > http://lxr.free-electrons.com/source/include/asm-generic/bug.h#L109
> >
> >
> > I don't see anything like it in Xen, so you'd need to either
> > implement
> > it, or arrange for something with the same effect locally.
> One of the reasons we don't (yet) have this is because commonly
> (like is the case here) printing such once globally isn't really what
> you want - you'd much rather see it once per domain.
>
Ah, I did not know that was part of the reason, but it makes sense.
However, for this specific case, I was also considering that, and I
agree, if possible/not to difficult to implement, once per domain would
indeed be better.
Regards,
Dario
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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next prev parent reply other threads:[~2016-03-14 10:05 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
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 [this message]
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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