QT core lib performance?

[Quentin]

Hi Guys,

I am new to QT. Right now we are going to develop an application cross Linux and Windows platform. The application will be heavy workload: more than 200 threads and frequent IPC plus disk I/O.

QT provides a good platform that has already covered the OS portability. But we are hesitating if QT core library can provide the good enough performance, especially thread, d-bus, sharedmemory and file I/O :confused.

Have any benchmarks been done regarding to QT performance evaluation? How's the performance based on your experience?

Appreciate your help in advance!

Best regards,
Quentin

[wysota]

Well... multithreading, shared memory and d-bus are all done outside the library, so it doesn't introduce any slowdowns itself. File I/O depends on the way you use it - if you use QFile directly then it is faster than using it through QTextStream for example. A potential slowdown may also come from the fact that Qt uses additional buffers so the time between calling the write() method to the data actually being written to disk migh increase a bit compared to using fprintf() or ::write().

On the other hand Qt is very fast when it comes to data manipulation especially when using Qt's container classes and shared classes. This has been benchmarked as shows much better results than STL for example.