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

[Harri Pasanen]

Have you ruled out network problems?    I've often seem similar "inexplicable" 
behavior when some network path (remote share) is being accessed.

For instance python startup from a network share is often a no-no, as it 
crawls through the python path.  Qt plugin paths could well trigger the same 
symptoms.

Just my 2 cents of educated guessing...


On Thursday, October 07, 2010 03:27:09 am Paul Miller wrote:
> 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?
> >> 
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-- 
Grego
http://mpaja.com/