KDirWatch and kdevelop idle CPU usage (4.7/1.7)

[René J.V. Bertin]

On Monday April 20 2015 22:48:47 Milian Wolff wrote:

> It's a switch that picks the "best" option available. Afaik inotify on Linux, 
> then FAM, then QFSWatcher and then stat.

Something like that, yes.

> Independently, the user afaik still 
> has the ability to pick another option when multiple are available (required 
> e.g. for proper NFS support).

I vaguely recall that we had to override a new default after a kdelibs 4.12.x upgrade.

> > Anyway, QFileSystemWatcher isn't an option for the large projects where idle
> > usage becomes an issue with polling: kdevelop is aborted very quickly
> > because of too many open files :(
> 
> Aborted? Why that?!

In this case it was collateral damage so to speak:
QProcessPrivate::createPipe: Cannot create pipe 0x7fe5569d2e18: Too many open files

* thread #1: tid = 0x7bd6fe, 0x00007fff89041e20 libsystem_kernel.dylib`__wait4 + 8, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
  * frame #0: 0x00007fff89041e20 libsystem_kernel.dylib`__wait4 + 8
    frame #1: 0x000000010f1efaae libkdeui.5.dylib`KCrash::startProcess(int, char const**, bool) [inlined] startProcessInternal(argc=<unavailable>, directly=<unavailable>) + 265 at kcrash.cpp:556
    frame #2: 0x000000010f1ef9a5 libkdeui.5.dylib`KCrash::startProcess(argc=<unavailable>, argv=<unavailable>, waitAndExit=<unavailable>) + 21 at kcrash.cpp:538
    frame #3: 0x000000010f1eebd9 libkdeui.5.dylib`KCrash::defaultCrashHandler(sig=<unavailable>) + 1209 at kcrash.cpp:441
    frame #4: 0x00007fff8eee65aa libsystem_platform.dylib`_sigtramp + 26
    frame #5: 0x00000001209f5ee5 libsvn_subr-1.0.dylib`svn_config_set + 30
    frame #6: 0x00000001208dc6f6 kdevsubversion.so`svn::Context::Data::Data(this=0x00007fe556693600, configDir_=<unavailable>) + 630 at context.cpp:216
    frame #7: 0x00000001208dc122 kdevsubversion.so`svn::Context::Context(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) [inlined] svn::Context::Context(this=0x00007fe5560656d0, configDir=<unavailable>) + 34 at context.cpp:637
    frame #8: 0x00000001208dc100 kdevsubversion.so`svn::Context::Context(this=0x00007fe5560656d0, configDir=<unavailable>) + 16 at context.cpp:638
    frame #9: 0x00000001208b10ee kdevsubversion.so`SvnInternalJobBase::SvnInternalJobBase(this=0x00007fe556693440, parent=0x00007fe556693270) + 94 at svninternaljobbase.cpp:49
    frame #10: 0x00000001208c208f kdevsubversion.so`SvnInfoJob::SvnInfoJob(this=0x00007fe556693270, parent=<unavailable>) + 95 at svninfojob.cpp:96
    frame #11: 0x00000001208a6cce kdevsubversion.so`KDevSvnPlugin::isVersionControlled(this=<unavailable>, localLocation=0x00007fff51ec8bc0) + 62 at kdevsvnplugin.cpp:108
    frame #12: 0x000000010ddc908f libkdevplatformshell.8.dylib`KDevelop::ProjectPrivate::loadVersionControlPlugin(this=0x00007fe556660000, projectGroup=0x00007fff51ec8c70) + 831 at project.cpp:402


> > with if it keeps idle CPU usage down. It'd be more annoying if the
> > detection of external changes to open files is affected too.
> 
> It is also affected afaik.

We'll see whether I'll want to increase or decrease the polling frequency.
I could also see if there doesn't exist a native method on OS X...

Cheers,
R.