Qt Components under 15.08

[Christian Helmuth]

Hello Marcus,

On Tue, Sep 29, 2015 at 02:38:46PM +0200, Marcus Nolte wrote:
> In my case I stumbled upon the file descriptor limit when using qt.
> Removing a certain number of qt-enabled components fixed the issue.
> Removing "conventional" componentes (most of them with libc dependency) 
> did not do any good.
> 
> Does the qt dependency cause that many additional sockets / temporary 
> files / whatever to be created, compared to
> "normal" components?

I guess that the core component runs out of file/socket descriptors
for RAM dataspaces. You may check by running a scenario with many
components and executing

  ls -l /proc/$(pidof core)/fd

which lists all file descriptors in use by the core component. I think
it's needless to say you may also investigate your Qt components this
way. For me

  make run/qt5

which runs just qt_launchpad produces

  440 fds in core

It's also worthwhile to look at the address space of qt_launchpad.
This single component uses about 60 mmap'd files for the binary,
ld.lib.so, all libraries, and stacks of created threads.

Regards
-- 
Christian Helmuth
Genode Labs

http://www.genode-labs.com/ · http://genode.org/
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