FET, Qt, and the C++ compiler performance

[Liviu Lalescu]

Qt 6.0.0 was released today. I compiled FET with different configurations on my 64-bit openSUSE Tumbleweed GNU/Linux and Ryzen 2700x processor.

The test file was file fet-5.48.1/examples/Germany/secondary-school-1/using_subactivities_constraints/German_subact_constr.fet

---
The random seed at the start of generation is:
   s10=1, s11=0, s12=0,
   s20=1, s21=0, s22=0.

This file was automatically generated by FET 5.48.1.
---

The random seed at the end of generation is:
   s10=1972339888, s11=2596370048, s12=2086588771,
   s20=325940581, s21=3598730718, s22=2398546905.

This file was automatically generated by FET 5.48.1.
---

Running times for the file and random seeds above:

FET-5.48.1 compiled with gcc, Qt 5.15.2: ~49 sec (this is the default assumed compilation on GNU/Linux and also this is how I provide the precompiled Windows version).
FET-5.48.1 compiled with gcc, Qt 6.0.0: ~44 sec.
FET-5.48.1 compiled with clang, Qt 5.15.2: ~43 sec.
FET-5.48.1 compiled with clang, Qt 6.0.0: ~39 sec.

Note that for other .fet input files the update to Qt 6.0.0 is not so beneficial, but it seems that in general it means about a 10% improvement compared to Qt 5.15.2.

So, if we switched to clang and Qt 6.0.0, we could obtain maybe an ~20% improvement of generation time.

But unfortunately on Windows systems Qt 6.0.0 only runs on Windows 10 64-bit. So you cannot run it on Windows 7, 8, or 8.1 (64 or 32-bit), or on Windows 10 32-bit. And I am sure we have lots of Windows 7 users of the precompiled FET.

I also am not sure if clang is to be chosen over of gcc. I am not sure who controls it and its license.

[bachiri401]

great news 20% faster


please go ahead with this nice development


many thanks indeed 

[Liviu Lalescu]

  You are welcome!

But it will take a while if and when we will switch.