Profiling Qt app with very Sleepy , how to analyze the results?

Question

Im trying to find why my Qt application get delay in some point for second , this sec delay happens each add to list operation , and way i used the free profiler "Very Sleepy" and it gave some snapshot that i have hard time to analyze. here is the top snapshot : first of all it seams that this winapi methods takes long:

Name,Exclusive,Inclusive
    GetModuleFileNameA,983.451654,983.451654,87.500001,87.500001,kernel32,[unknown],0 

and there is no stack print . the second method that taks long is :

GetLastInputInfo,128.507105,128.507105,11.433579,11.433579,USER32,[unknown],0

and in this stack trace i see heavy calling to QSettings::allKeys coming from QtCore4 i dont call QSettings::allKeys

and then i have :

QPixmap::alphaChannel,1.159998,140.493087,0.103208,12.499999,QtGuid4,[unknown],0

and here i do create images from bytarray info i download from the web , small 50X50 images using :

QImage thumbnail = QImage::fromData(bytarray );

how can i save here and maybe stop this app delays?

Answer 1

Completely out of subject but I do recommend to use intel vtune a more user-friendly profiler. You can visualize both CPU utilization over time (by thread) and time spent in a particular function\\line of code.

But what actually amazed me was to be able to compare 2 different results, really useful to verify how a change influence performance. Give it a try, I guarantee you would be disappointed.