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From: Dario Faggioli <dario.faggioli@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	Kelly Zytaruk <Kelly.Zytaruk@amd.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: Question regarding Xen scheduler
Date: Fri, 24 Oct 2014 16:55:42 +0200	[thread overview]
Message-ID: <1414162542.17454.45.camel@Abyss> (raw)
In-Reply-To: <5437B0FD020000780003D882@mail.emea.novell.com>


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On Fri, 2014-10-10 at 09:12 +0100, Jan Beulich wrote:
> >>> On 08.10.14 at 15:57, <andrew.cooper3@citrix.com> wrote:
> > On 08/10/14 14:05, Zytaruk, Kelly wrote:
> >> What if I am doing something time critical or sequence critical that can't 
> > be interrupted?  Is there a way to tell the Xen scheduler that "I am in a 
> > critical section and can't be interrupted by another Dom" so that Xen won't 
> > task switch until I am done?
> > 
> > No.
> 
> But I'd like to note that suggestions to add some mechanism to
> allow this have been made more than once in the past.
> 
And it does seems sensible, as a mechanism, at least IMO. However, the
problem, as often in scheduling, especially when dealing with a complex
architecture, such as Xen's one, would be how to use it "right"...
Assuming we even know what "right" means in this case.

In fact, this is the typical thing that can bring a lot of benefits in
one situation/workload, and at the same time disrupt substantially
another one! :-/

For instance, Kelly, if I can ask, how where you thinking to use it, if
it were there?

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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  reply	other threads:[~2014-10-24 14:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-08 13:05 Question regarding Xen scheduler Zytaruk, Kelly
2014-10-08 13:57 ` Andrew Cooper
2014-10-08 14:03   ` Razvan Cojocaru
2014-10-08 15:05     ` Zytaruk, Kelly
2014-10-08 14:03   ` Zytaruk, Kelly
2014-10-10  8:12   ` Jan Beulich
2014-10-24 14:55     ` Dario Faggioli [this message]
2014-10-24 20:26       ` Zytaruk, Kelly
2014-10-27  9:18         ` Jan Beulich

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