[Interest] Qt Quick Compiler (Interest Digest, Vol 38, Issue 51)

Turunen Tuukka tuukka.turunen at theqtcompany.com
Sat Nov 15 07:54:59 CET 2014


Hi Harri,

Our measurements with Qt Quick Compiler 1.0 with different kind of projects indicate that a typical mid-sized Qt Quick application startup is 30-40% faster with compiled Qt Quick. This is an excellent improvement and we believe we can improve this even more in the future. The highest startup time improvements we’ve gotten are as high as 90% in the case where the application is very JavaScript intense and contains no other items, like graphics, to load at startup.

I do agree that we should provide more metrics and also provide to others validate these. However the most relevant question is how much is the improvement in Your use case. Best way to check that is to try. There are, of course, many other things to optimize startup time. After these are all done, QQC still shaves some time away from the startup.

Yours,

--
Tuukka

> Harri Pasanen <harri at mpaja.com> kirjoitti 14.11.2014 kello 17.09:
> 
> Actually I was less interested in the compilation time than what it is 
> the return for the investment.
> 
> Reading the compiler docs, they recommend disabling the compilation for 
> debug builds, as it can interfere with debugging. So through configure 
> the build/deploy cycle should stay the same for debug builds.  Of course 
> in reality you will need to do a couple of rounds of testing with 
> release builds as well.
> 
> But nobody has mentioned any figures on the speed gains resulting from 
> using the compiler.
> 
> A related question, has anyone tried to coax QML, or rather the 
> javascript components through the Closure Compiler?
> https://developers.google.com/speed/articles/compressing-javascript
> 
> It might help a little, especially with javascript heavy QML, as it 
> would reduce the working set size / cache misses, etc.
> 
> Idle thoughts,
> 
> Harri
> 
> 
>> On 14/11/2014 13:24, rpzrpzrpz at gmail.com wrote:
>> Then that would make the benchmarks that Harri requested a mute point.
>> 
>> Unless you "make clean", the incremental build would not care about
>> 10,000 lines of QML code. It would only "slow" down on the changed QML.
>> 
>> Is there an option to turn off the Quick Compiler for beta builds and
>> only kick it on during release?
>> 
>> md
>> 
>> 
>>> On 11/14/2014 3:01 AM, Portale Alessandro wrote:
>>> According to a quick test I did just now, with Qt 5.4-beta (Qt Quick Compiler 2.0) on msvc2013, it only re-compiles the changed qml files.
>>> 
>>> Best regards,
>>> Alessandro Portale
>>> ________________________________________
>>> Betreff: Re: [Interest] Qt Quick Compiler
>>> 
>>> Does the quick compiler only re-compile those QML files that were
>>> changed or does it re-compile ALL QML every time regardless of changes
>>> to the QML files or not?
>>> 
>>>> On 11/13/2014 8:10 PM, Yang Fan wrote:
>>>> I have not test the running improvement. But I can tell you that it slow
>>>> down the build process significantly if you have many QML files. Every
>>>> QML file will be converted to a cpp file which will be compiled, you
>>>> know the C++ compiler is very slow.
>>>> 
>>>> On Thu, Nov 13, 2014 at 11:42 PM, Harri Pasanen <harri at mpaja.com
>>>> <mailto:harri at mpaja.com>> wrote:
>>>> 
>>>>     Hi,
>>>> 
>>>>     Are there benchmarks on how  much start-up time is improved with the Qt
>>>>     Quick compiler?
>>>>     Say I have 10000 lines of QML on Android, any idea how many percent gets
>>>>     shaved off the start-up time?
>>>> 
>>>>     Is the improvement identical across platforms, iOS, Android, desktop
>>>>     ...?
>>>>     Is the compiler itself fast, will it slow down the build/deploy cycle
>>>>     significantly?
>>>> 
>>>> 
>>>> 
>>>>     Curious,
>>>> 
>>>>     Harri
>>>> 
>>>> 
>>>> 
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>>>> 
>>>> 
>>>> 
>>>> 
>>>> --
>>>> Regards,
>>>> Fan Yang
>>>> 
>>>> 
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