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From: Dario Faggioli <dario.faggioli@citrix.com>
To: George Dunlap <george.dunlap@citrix.com>, xen-devel@lists.xenproject.org
Cc: Anshul Makkar <anshul.makkar@citrix.com>,
	David Vrabel <david.vrabel@citrix.com>
Subject: Re: [PATCH v2 03/11] xen: credit2: rework load tracking logic
Date: Mon, 18 Jul 2016 16:51:37 +0200	[thread overview]
Message-ID: <1468853497.13039.145.camel@citrix.com> (raw)
In-Reply-To: <341508b6-7c22-fffa-97ff-6932b2a019e0@citrix.com>


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On Mon, 2016-07-18 at 15:46 +0100, George Dunlap wrote:
> On 15/07/16 15:49, Dario Faggioli wrote:
> > 
> > This may look handy, but it introduced a (not especially well
> > documented) dependency between the lenght of the window and
> > the precision of the calculations, which really should be
> > two independent things. Especially if treating them as such
> > (like it is done in this patch) does not lead to more
> > complex maths (same number of multiplications and shifts, and
> > there is still room for some optimization).
> > 
> > Therefore, in this patch, we:
> >  - split length of the window and precision (and, since there
> >    is already a command line parameter for length of window,
> >    introduce one for precision too),
> >  - align the math with one proper incarnation of exponential
> >    smoothing (at no added cost),
> >  - add comments, about the details of the algorithm and the
> >    math used.
> > 
> > While there fix a couple of style issues as well (pointless
> > initialization, long lines, comments).
> > 
> > Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> > ---
> > Changes from v1:
> >  * reconciled comments and actual code about load_window_shift
> > handling;
> And this apparently means changing the code to match the comments
> (not
> the other way around), so that the actual load_window_shift default
> is
> now 30 (as the comments say) instead of 20 (as it was in the previous
> patch). :-)
> 
Indeed. I should have made it more clear that this is what's
happening... Sorry! :-)

> Reviewed-by: George Dunlap <george.dunlap@citrix.com>
> 
Thanks,
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:[~2016-07-18 14:51 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-15 14:49 [PATCH v2 00/11] xen: sched: assorted fixes and improvements to Credit2 Dario Faggioli
2016-07-15 14:49 ` [PATCH v2 01/11] xen: sched: leave CPUs doing tasklet work alone Dario Faggioli
2016-07-18 14:35   ` George Dunlap
2016-07-15 14:49 ` [PATCH v2 02/11] xen: credit2: prevent load balancing to go mad if time goes backwards Dario Faggioli
2016-07-15 14:49 ` [PATCH v2 03/11] xen: credit2: rework load tracking logic Dario Faggioli
2016-07-18 14:46   ` George Dunlap
2016-07-18 14:51     ` Dario Faggioli [this message]
2016-07-15 14:49 ` [PATCH v2 04/11] xen/tools: improve tracing of Credit2 load tracking events Dario Faggioli
2016-07-18 15:38   ` Wei Liu
2016-07-15 14:49 ` [PATCH v2 05/11] xen: credit2: use non-atomic cpumask and bit operations Dario Faggioli
2016-07-15 14:49 ` [PATCH v2 06/11] xen: credit2: make the code less experimental Dario Faggioli
2016-07-18 15:04   ` George Dunlap
2016-07-15 14:49 ` [PATCH v2 07/11] xen: credit2: add yet some more tracing Dario Faggioli
2016-07-15 14:50 ` [PATCH v2 08/11] xen: credit2: only marshall trace point arguments if tracing enabled Dario Faggioli
2016-07-18 15:10   ` George Dunlap
2016-07-15 14:50 ` [PATCH v2 09/11] tools: tracing: deal with new Credit2 events Dario Faggioli
2016-07-18 15:39   ` Wei Liu
2016-07-15 14:50 ` [PATCH v2 10/11] xen: credit2: the private scheduler lock can be an rwlock Dario Faggioli
2016-07-15 14:50 ` [PATCH v2 11/11] xen: credit2: implement true SMT support Dario Faggioli
2016-07-18 16:48   ` George Dunlap
2016-07-18 17:24     ` Dario Faggioli
2016-07-19  9:39       ` George Dunlap
2016-07-19  9:57         ` Dario Faggioli
2016-07-19 10:05           ` George Dunlap
2016-07-19 10:19             ` Dario Faggioli
2016-07-18 17:21 ` [PATCH v2 00/11] xen: sched: assorted fixes and improvements to Credit2 George Dunlap

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