[Sugar-devel] ASLO

James Cameron quozl at laptop.org
Wed May 21 19:44:12 EDT 2014

On Wed, May 21, 2014 at 10:03:47PM +1000, Sam Parkinson wrote:
> Oops, forgot to reply-all :)


> On May 21, 2014 9:58 PM, "Sam Parkinson" <sam.parkinson3 at gmail.com> wrote:
> > On Wed, May 21, 2014 at 8:20 AM, James Cameron <quozl at laptop.org> wrote:
> >> What's the Flash element for?
> > Sorry, I'm not exactly sure what the Flash element is.

Nor I.  I'm using Firefox, configured to ask before running Flash, and
it asks, so that means the page is trying to run something.

But in a quick search I wasn't able to find what Flash is actually
being run.  Maybe it is something in persona.org.  Do you really need
to uyse persona.org?

While looking for the cause, I assessed the network load for your

- with an empty cache, a total of 23 GET requests to 10 different
  servers, for a total of 491 KB of data,

- with a primed cache, a total of 11 GET requests to 10 different
  servers, for a total of 65 KB of data,

- the slowest response of 1550 ms was from
  aslo-bot-master.sugarlabs.org, and this large response time
  persisted on repeated refreshes.

Comparing to activities.sugarlabs.org which, at the moment, has more

- with an empty cache, a total of 40 requests to just one server, for
  a total of 381 KB of data,

Because the requests were to just one server, the original ASLO loads
much much faster.

By splitting the requests among multiple servers as you have done:

- the browser can't queue multiple GETs in the same HTTP connection,

- the browser must negotiate several new HTTP connections, each with a
  round trip delay,

- the web site depends on multiple servers, so the mean time between
  failure (MTBF) is dramatically reduced.  See [1].

This is even more important for XO laptops, because they are usually
connected over wireless, with varying network latency.

You might work to place all the resources you use on one server, and
find out why 12 KB of data.json from aslo-bot-master.sugarlabs.org
takes such a surprising time to load.

Hope this helps.

[1]  if server A has an MTBF of one day, and server B has an MTBF of
one day, the combined MTBF is half a day.  Without knowing the MTBF of
each server, you can guess at a failure once a day or once a week, and
so for 10 servers the MTBF will range from once every tenth of a day
to once every tenth of a week.

> >> When I click on "Review the activity" nothing happens except a
> >> text cursor appears.
> >
> > Ah, that is a textbox, I changed that to "Type your review..."

Interesting.  That's not what a textbox normally looks like, and it
isn't clear where the review should be typed.  For instance, if you
just start typing, nothing happens, you have to first click in the
"Type your review" area.  So you can't obey the instructions.

Normally a textbox is empty, and is identified as a place you can
type, and a separate element is used to give the purpose of the

The same can be said of the Search... textbox.

> >> The "Download" and "Post" buttons could be made into icons.
> >
> > I made some changes, what do you think?

I see you added icons to the text.  Perhaps I should have been
clearer; the text needs to be in several languages, but an icon
doesn't need to be.  That's one of the reasons icons are used.

> >> The icons could do with mouse-over hints in the current language.
> >
> > Did that for the review types just then :) Any others that need it
> > :)

All of them, of course.  How else will people know what they will do?

James Cameron

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