[Qt-interest] Qt 4.6.3 QApplication constructor (Windows 7) EXTREMELY slow?

[Paul Miller]

On 10/6/2010 6:40 PM, william.crocker at analog.com wrote:
> Can you profile one of the slow starts.
> On Linux I would use Quantify.
> On windows?

I'm on Windows. And unfortunately I can't profile because installing any 
development tools changes the environment. Like I mentioned, on my dev 
machine with all those tools available, the problem never occurs.

>
> Paul Miller wrote:
>> Just spent the last 2 days tracking down an intermittent performance
>> problem with QApplication construction.
>>
>> Symptoms:
>> 1. on my machine, everything was fast - QCoreApplication would
>> initialize consistently in about 60ms (release mode)
>>
>> 2. on 2 tester machines, and on a completely clean Windows 7 x64 VM, the
>> same app would start up sporadically quickly, but then every now and
>> then (every 5-10 runs) would take about 16 seconds longer on the 2 test
>> machines, and about 10 seconds longer on the VM.
>>
>> 3. after awhile, the test app would ALWAYS take 10 seconds longer than
>> usual to start up on the VM (as I said none of this happened on my dev
>> machine so the VM was all I had available to test with). Results were
>> consistent with 2 off-site test machines.
>>
>> I switched back to 4.5.3 Qt dlls and everything started working properly
>> on all machines, and QApplication init time went down to about ~1ms.
>>
>> Note all of the test machines were fairly clean, with no standard Qt
>> installation and pretty stock runtimes/patches installed. Basically just
>> test app + required Qt dlls in a directory. Development machine was
>> loaded with Visual Studio, various runtimes, various Qt installs, etc. etc.
>>
>> Anyone seen anything like this? Is Qt 4.6.3 doing something radically
>> different during app startup now?
>>
>> _______________________________________________
>> Qt-interest mailing list
>> Qt-interest at trolltech.com
>> http://lists.trolltech.com/mailman/listinfo/qt-interest
>>
> _______________________________________________
> Qt-interest mailing list
> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest
>