jon.nettleton at gmail.com
Thu Jul 4 02:29:12 EDT 2013
On Thu, Jul 4, 2013 at 8:19 AM, James Cameron <quozl at laptop.org> wrote:
> On Wed, Jul 03, 2013 at 11:03:17PM -0700, Yioryos Asprobounitis wrote:
> > ----- Original Message -----
> > > From: James Cameron <quozl at laptop.org>
> > > To: Yioryos Asprobounitis <mavrothal at yahoo.com>
> > > Cc: OLPC Devel <devel at lists.laptop.org>
> > > Sent: Thursday, July 4, 2013 8:44 AM
> > > Subject: Re: XO-1(.75)
> > >
> > > On Wed, Jul 03, 2013 at 10:02:15PM -0700, Yioryos Asprobounitis wrote:
> > >> ----- Original Message -----
> > >>
> > >> > From: James Cameron <quozl at laptop.org>
> > >> > To: Yioryos Asprobounitis <mavrothal at yahoo.com>
> > >> > Cc: OLPC Devel <devel at lists.laptop.org>
> > >> > Sent: Thursday, July 4, 2013 2:10 AM
> > >> > Subject: Re: XO-1(.75)
> > >> >
> > >> > On Wed, Jul 03, 2013 at 02:21:08PM -0700, Yioryos Asprobounitis
> > >> >> I'm using the XO-1.75 a bit more these days and gives me a
> > > sense of
> > >> >> XO-1 performance wise. So I compared my (500/200 overclocked)
> > > XO-1
> > >> >> running F14/os885/Sugar-0.94 to XO-1.75 running
> > >> >> F-18/13.2.0-11/Sugar-0.98.
> > >> >
> > >> > Since some general performance work was done between those software
> > >> > versions, the comparison is uninteresting. Compare 13.2.0-11
> > >> > XO-1 and XO-1.75, or compare XO-1 across os885 and 13.2.0-11,
> > >> > depending on what you are looking to prove.
> > >>
> > >> This comparison has been done a couple of months ago and is clear
> > >> that F18/S0.98 taxes the systems considerably.
> > >
> > > Yes, it does seem that way. I tried 13.2.0-n on XO-1 recently and
> > > felt it was quite slow, but I couldn't be sure it wasn't because my
> > > XO-1.75 and XO-4 experience influenced me.
> > >
> > >> What I found interesting in this "unmatched" comparison was the
> > >> inconsistency.
> > >
> > > I don't see any inconsistency though, because the comparison was
> > > unmatched to begin with. Variables you changed included overclocking,
> > > the CPU, the memory, the internal storage, the touchpad, the kernel,
> > > the base operating system, the frame buffer, the X server, the OLPC
> > > utilities, and Sugar. All I can draw from the results is that you
> > > changed a lot of things and a lot of things were different.
> > But this is exactly the point!
> > When a _lot_ of things are changing and you have two groups of
> > activities one going one way and the other the opposite, you look
> > for the "least common denominator" that will hopefully point to the
> > problem (this is is a very common approach in multi-variable
> > problems).
> Oh good, now I understand.
> > >
> > >> They might point to specific stacks in the
> > >> architecture and/or core OS that may need attention (I originally
> > >> thought was that activities with an extended non-python component or
> > >> proportionally less gtk3, fair better on the XO-1.75 - but what do I
> > >> know ;).
> > >> Anyway, if the knowledgeable believe there is nothing to it or
> > >> anything to be done about it,' there goes the comparison.
> > >
> > > We wait for someone who seems interested in fixing performance
> > > problems on the old hardware. It requires quite a depth of knowledge
> > > and a lot of time. It isn't something that we can justify a huge
> > > investment in.
> > >
> > I would think that the performance of newer hardware may be the one
> > that needs attention but certainly can not prioritize it (unless if
> > XO-1.75 classifies under "older" by now).
> XO-1.75 and XO-4 are current, but XO-1.5 and XO-1 are old.
> We are certainly interested in any ways to make clear performance
> improvements on XO-1.75 and XO-4.
There is performance work that has been done for the XO-1.75 that is still
in the queue to be implemented in the OLPC builds. It is on my list for
the summer to get this work cleaned up and published in a repo for
developer and end user consumption. The performance gains are due to work
done by Matt Turner implementing iWMMXt acceleration in pixman, as well as
other libraries that when compiled with this support get some performance
boosts. Mostly graphics and multimedia apps will benefit from this tuning.
On top of that both the XO-1.75 and XO-4 will get graphics performance
boosts when I finish up my graphics driver that allows cached pixmaps to be
used. We have to do some graphics rendering and manipulations with the CPU
instead of the 2D core and we hit a performance bottleneck with the way
pixmaps are allocated for use by the graphics engine.
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