[Sugar-devel] Vision

[Dave Crossland]

Hi

On 20 April 2016 at 18:27, James Cameron <quozl at laptop.org> wrote:

> On Wed, Apr 20, 2016 at 05:22:21PM -0400, Dave Crossland wrote:
> >
> > On 20 April 2016 at 16:46, James Cameron <[1]quozl at laptop.org> wrote:
> >
> >     the performance ratio between our low-cost
> >     low-power hardware and the competition was already evident on Fedora
> >     Linux; it didn't need Windows to expose it
> >
> > Sorry if this is an obvious question, but, can anything done to make
> > Sugar feel faster on XO-1s today?
>
> Yes, and I've been doing some of that in the past few months.


AWESOME


> With 13.2.7 you have my latest work, which added swap and removed several
> animations.
>

Great :)


> Adding swap has mostly removed memory pressure.


Is it possible to configure the swap to run on the SD card, which, if
failing due to thrashing, can easily be replaced?


> Under memory
> pressure, activity startup is roughly doubled,


WOW


> as the CPU spends time thrashing in the memory management.

Disadvantage is higher power cost
> and possibly decreased Flash endurance, although the endurance of a
> set of heavily used XO-1 has shown no sign of the deterioration
> expected by now.
>

Yes, it is somewhat astonishing to me that any XO-1 are still working at
all :) I would have thought they'd all have cracked screens and ripped
keyboards by now.

Maybe this was brought up on the XO-1 thread I started, but I didn't
remember if so; does anyone has any suggestions about how many XO-1s are
still in use?


> Removing animations has allowed CPU cycles to be better spent on
> responsiveness.  At one stage we had 50/50 competition between the
> activity launch animation and the starting activity.


Woah :)


> Instrumenting
> the frame and transition box animations showed there was enough time
> for only one or two intermediate animation states before the final
> state; which turned out to the cost of handling the function key
> release event.  Some of these changes are not in Sugar master yet, but
> in an OLPC branch; one such was proposed, but immediately closed with
> appeal to process;
>
>         https://github.com/sugarlabs/sugar/pull/619


I sympathise with Sam's request to discuss further; eg, perhaps there is a
compromise by wrapping the decision to animate in an if/else block that
checks some cpuinfo in /proc, or if the number of running activities can be
obtained very cheaply through a len() call or something?


> As for what to do next; ideas are welcome, but here's a few;
>
> - profiling, of startup, of interactive response, (i've used xdotool
>   for interactive response tests),
>

AWESOME! Could you make a screencast showing how to set this up?


> - upgrade Gtk3, and GObject, to fix the memory leaks,
>

I like it!


> - record metrics of response, deidentify, aggregate, and report.
>

I think this kind of data driven development is crucially important :)


> Although at this stage the interest in XO-1 should have degraded as
> the units have degraded, and any return on investment is doubtful.
>

I'm not sure; even if the XO-1 units themselves are gone, the cheapest
computers will always be puny, either (non-)refurbished clunkers passed
down to kids, or $5 computers like the Raspbery Pi Zero.

By optimizing for XO-1, we optimize for spending power of small children.


> Plenty of people left who whinge about XO-1, but ask them to test a
> patch or release and no response.
>

Kindly, this is because you assume too much technical skills/experience on
their part, and I suspect that there is a "tact filter mismatch" per
www.mit.edu/~jcb/tact.html :)

This was/is also a brake on the speed of development of the fontforge
community, which is written in C and has its own X toolkit; the community
of C developers were generally unwilling to 'baby step' enthusiastic but
inexperienced community peers in how to apply and test patches.


> So it's more about people wanting their rainbow pooing unicorns.
> Unrealistic expectations, polarised framing, denial, and consequent
> unwillingness to be involved.


I am again reminded of https://youtu.be/N9c7_8Gp7gI?t=9m1s 9m1s to 10m23s
as an amusing anecdote about how to work productively with people who are
setting out to work against you :)

-- 
Cheers
Dave
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