Re: [Starpu-devel] Suggestions about creating starpu threads

[Andra Hugo <andra.hugo@inria.fr>]

Hi,

That sounds good!

Andra

----- Mail original -----
> De: "Fangli Pi" <hpcfapix@hlrs.de>
> À: "Andra Hugo" <andra.hugo@inria.fr>, "Samuel Thibault" 
> <samuel.thibault@inria.fr>
> Cc: "starpu-devel" <starpu-devel@lists.gforge.inria.fr>
> Envoyé: Lundi 30 Mai 2016 09:04:22
> Objet: Re: Suggestions about creating starpu threads
> 
> Hi,
> 
> Sorry for the delay of reply.
> 
> Fangli
> 
> ----- Original Message -----
> From: "Andra Hugo" <andra.hugo@inria.fr>
> To: "Fangli Pi" <hpcfapix@hlrs.de>
> Cc: "starpu-devel" <starpu-devel@lists.gforge.inria.fr>, "Samuel Thibault"
> <samuel.thibault@inria.fr>
> Sent: Wednesday, May 25, 2016 6:46:11 PM
> Subject: Re: Suggestions about creating starpu threads
> 
> Hi,
> 
> Yes indeed we should first measure if this is actually a problem before 
> going
> into unnecessary modifications.
> 
> Sure, I will try to do the assessment of the effect on performance.
> 
> Of course as long as we use the tools just for training it should not be a
> problem. However, as far as I know RAPL bases their values on a model (IPC,
> cache misses, frequency etc.) they don't do actual hardware measurement of
> the voltage. So as Sam says, depending on what we executed before hand the
> frequency may change and affect the measurements. But I suppose this can
> happen anyway. Do you do any approximations for this?
> 
> Right now I don't have any approximations according to the frequency change,
> but I can have a look at it and try if it is possible.
> 
> So these measurements should be desactivated if STARPU_CALIBRATE = 0, right?
> 
> According to one of your reviews, I have added one environment to activate
> and deactivate the power measurements, named as STARPU_POWER_PROFILING,
> which determines if ex_starpu_init() is called or not.
>  
> Andra
> 
> > ----- Mail original -----
> > > De: "Samuel Thibault" <samuel.thibault@inria.fr>
> > > À: "Fangli Pi" <hpcfapix@hlrs.de>
> > > Cc: "Andra Hugo" <andra.hugo@inria.fr>, "starpu-devel"
> > > <starpu-devel@lists.gforge.inria.fr>
> > > Envoyé: Mercredi 25 Mai 2016 16:33:42
> > > Objet: Re: Suggestions about creating starpu threads
> > > 
> > > Fangli Pi, on Wed 25 May 2016 16:30:23 +0200, wrote:
> > > > After all, the performance during training is not so important, right?
> > > 
> > > Hurting the performance of the application is not very important indeed,
> > > as long as the performance of the tasks is preserved.
> > > 
> > > That said, if it really hurts the performance of the application, that
> > > could potentially change the energy consumption. If it's not too bad
> > > it's fine, but it'd be useful to assess it.
> > > 
> > > Samuel
> > > 
> >
> --
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> University of Stuttgart
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