[Interest] Qt 5.8 performance regression in android application

Лагнер, Сергей developer at lagner.ru
Thu May 11 12:27:38 CEST 2017

Hi, Tomas.

Your notice is very valuable. Indeed, we have significant amount of http
requests and
we start them right after page has been created. Therefore if it costs
much, transition
animation can freeze.
One thing I can not understand. I thought Qt makes almost all network
calculations in a
background thread. Is it not true?

Do you know the fix is going to be backported to 5.8? Or can I work around
As I see 5.9 is not ready yet.

One more thing, I can't find jira ticket about this regression. Can you
share it?

2017-05-11 14:59 GMT+07:00 Tomas Konir <tomas.konir at gmail.com>:

> Hi
> You wrote, that you have app which uses internet.
> If you are using many http requests, you may be affected with regression
> in network access manager, which computes DH keys for each http request
> (even though you are doing only plain http).
> DH computation is very CPU intensive and for me causes massive slowdown on
> android and noticeably slowdown on PC (http intesive application).
> This is fixed in upcoming 5.9.
> Tom
> 2017-05-11 9:45 GMT+02:00 Лагнер, Сергей <developer at lagner.ru>:
>> Hello all.
>> We are going to upgrade Qt from 5.6 to 5.8 for our android application.
>> I've got the build with Qt 5.8 and it much slower.
>> First of all I mean animations.
>> We use Qml StackView and we animate transitions between pages.
>> With 5.6 this animations are smooth, but with 5.8 they are laggy.
>> It freezes 3 or 4 times each transition.
>> One more example, we have a photo gallery page. All photos come from the
>> internet.
>> Once transition to the page is done, Qt 5.6 already has a number of
>> photos to show.
>> 5.8 only shows first picture after a while.
>> I know that my problem is not concrete enough, but maybe you know smth
>> that
>> was changed between 5.6 and 5.8 that is very important to check or modify
>> to get better performance.
>> We use QtQuickCompiler if it's matter.
>> _______________________________________________
>> Interest mailing list
>> Interest at qt-project.org
>> http://lists.qt-project.org/mailman/listinfo/interest
> --
> Tomas Konir
> Czech Republic
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