Very slow on some Windows systems

I got reports from clients that the latest version of my application is very slow. It seems that the app is very unresponsive on buttons, menus and opening and closing windows. I can reproduce it only on a laptop running XP sp2, all other computers (including another XP sp2 and Mac) are fine.

I took the Helloworld app and to my surprise it is also very slow on that computer. It takes ages to start and/or the Quit button is a few seconds unresponsive.

Then I took an older juce version, Aug 6, 2010, and built the Helloworld app again. This one is blazingly fast! My app build with that version of Juce runs smooth too.

Here are two screenshots of the verysleepy profiler, while pressing the Quit button:



Does anyone have seen this before?

I tried the stable versions 1.51 and 1.52, both run fast (Helloworld). Version from March 31 has speed problems, so the problem must have been introduced between December 21 2010 and March 31 2011. I have no version in between those dates.

I have similar reports about Windows XP slow GUI response (very slow), someone asked me to do a GCC build for windows but when building with the latest MINGW JUCE crashes on some PNG stuff (there is a topic in this forum about it), and i never got the build to work.

I found the Git commit where the problem begins. Its this one:;a=commit;h=37877037f46e061ba9bdf7f312e8ed7b1d04089e

Before is ok, both my app and the helloworld example.

Maybe this helps.

Well, I just dragged out my old XP machine and tried the latest demo app and hello-world on it, and it’s absolutely fine (??)

I don’t know if it is a XP problem, 1 of my XP machines is fine too. But the problem is very reproducable and disappears when building before that Git commit.

Would it be helpful if I undo the changes of that commit 1 by 1, so that we know what change causes this?

Yes, that’d definitely help! Since I can’t reproduce it, I can’t really think of anything else we could try.

Finally, an update on this… sorry that it took so long.

The bad news: it seems that it is impossible to undo the changes one by one

The good news: the very latest tip works flawlessly on that old XP system, so I think this matter can be closed!