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Slow Debugger

  • I am using Qt Creator 4.7.0, Help/About says it was built on MSVC 2015 64 bit. However, I am using the MinGW 32 bit tool chain that came with the installation. OS is Windows 8 64 bit. I have been debugging the same fairly large application for over a week, but now it has become so slow to startup a debugging session it has become impossible to work effectively. My question is, are there some temporary files that maybe can delete to reset the debugger? Again, it worked fine for some time but over the last day or so, it has become progressively slower. I see older posts about slowness, but they are all very old.

  • Lifetime Qt Champion

    Is it also slow with default GUI app ?
    I have not heard about slowdown before so not sure what it could be.
    You could remove Qt and add it again and see.

  • Not sure what you mean by the default GUI app? Do you mean if I compile my project in release mode? Running in Creator, similar issue, very slow. But if I bundle the release product all together in an install package then install and run it, it is OK.

  • Does restarting creator / your PC fix it?

    From my memory I can aggravate it playing with local / expression and cause it to bomb the locals out messing with a vector that was being iterated... something like that, anyhow, I notice it because I lose all my locals and watches, all go white/missing... it's best just to stop debugging, restart creator.

    Do you notice anything like this? My feeling is it upsets something in gdb or something, I've just restarted creator at least when it runs like crap or when I lose my locals. Usually I reboot if I'm going to break work like restarting the ide

  • I've tried all that: restarting Creator, logout/login from Windows, shut down/reboot. Nothing seems to help. I do note occasionally (other issue) the box that displays the local variables will either go blank, or not respond when I try to expand on a complex one. But, again, that may be a separate issue from the slowdown I am currently experiencing. I have seen that even when the IDE seems more responsive.

  • @nekkceb well, I'd say from my experience anyhow, losing the locals is the precursor to slowdown (for me) and I can't recover the locals after that point. Sometimes as it swaps files but it's never quite right.

    I usually break the locals by messing with a vector during an iterator or range loop and trying to mess with an element by index or something else like that.

    Have you done static analysis like valgrind or clang? Perhaps you've also got some gremlins?

    Or console logging - are you doing a shit ton of writes to console?

  • Lifetime Qt Champion

    @nekkceb Did you try to disable anti-virus software? How is the memory consumption on your machine?

  • @6thC Looks like Valgrind is not available for Windows? Tried Clang, lots of messages, all warnings. I've cleaned up many, but this slowdown issue just started recently, and I've only done minor changes since, just trying to debug one particular routine.
    I just un-installed and re-installed Qt, no chnage!

  • @nekkceb This is correct, valgrind is linux only, Clang's does good things too.
    I just have access to both so use as many tools that pick up on my potential mistakes as I can get my hands on really.

    How about your console logging - are you doing logging heaps? I was console logging mutex lock and unlocks. That also got things really upset. File logging also selective logging (logging categories) has helped me there too.

  • @jsulm It seems to be fixed, but I am not sure what did it. I performed a complete sweep for viruses an malware, nothing major found. Then switched to Win10 (I go back and forth between win8 and win10), and for a while my app would not even start, with a error 0xc0000139. Did a search for that error on the web, not much help. Used depends.exe to see what DLLs were getting loaded, but found out that is a dead project, not applicable to win10. Updated a third party app I link into. Then win10 decided to do an update, which fixed the 0xc0000139 error. I cleaned up some logging events, and that improved the slow startup issue, but I cant believe that was the entire fix. Given I did so much in no certain order, in the end I cant identify what did the trick!

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