[Interest] porting to Qt 5.4 - MOC very slow on Windows

[Koehne Kai]

> -----Original Message-----
> From: interest-bounces+kai.koehne=theqtcompany.com at qt-project.org
> [mailto:interest-bounces+kai.koehne=theqtcompany.com at qt-project.org]
> On Behalf Of Hamish Moffatt
> Sent: Thursday, January 15, 2015 7:34 AM
> To: interest at qt-project.org
> Subject: [Interest] porting to Qt 5.4 - MOC very slow on Windows
> 
> I'm trying to port our app from Qt 4.8 to 5.4. Currently working in MSVC 2013,
> and using the pre-built Qt binaries for that environment.
> 
> We have about 440 files being MOCed during build. On 5.4, each file is taking
> 2-3 seconds meaning the overall build is significantly longer than in 4.8.
> 
> I found a reference to a similar problem here -
> http://qt-project.org/forums/viewthread/47901 - which was due to using
> MOC on a network drive. In my case everything is on local SSD.
> 
> Any suggestions?

IIRC moc in Qt 5 got much more accurate in the parsing phase, which might mean it now parses included headers that it previously missed.

2 - 3 seconds is quite long though ... Maybe running procmon.exe to monitor all file accesses done by moc gives you a hint?

Regards

Kai