[Interest] Qt 5.8 performance regression in android application
tomas.konir at gmail.com
Thu May 11 13:08:35 CEST 2017
2017-05-11 12:27 GMT+02:00 Лагнер, Сергей <developer at lagner.ru>:
> 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?
Network calculations are processing on background thread, but i expect,
that you are creating QNetworkRequest in main thread.
DH calculations are in QNetworkRequest constructor.
You can simple measure how long takes new QNetworkRequest() on 5.6 and 5.8
(android is best testing platform for this due to lack of CPU power)
> 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.
Current 5.8 is unfixed. Maybe 5.8.1 if it will exists.
5.9 is close to beta and should be ready in two or three weeks (i hope
because i have similar problem)
> 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>:
>> 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.
>> 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
>>> 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
>>> was changed between 5.6 and 5.8 that is very important to check or
>>> to get better performance.
>>> We use QtQuickCompiler if it's matter.
>>> Interest mailing list
>>> Interest at qt-project.org
>> Tomas Konir
>> Czech Republic
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