Hello everyone

Could anyone tell me why threads are set to not inherit scheduling parameters from the calling thread?

http://svn.freepascal.org/cgi-bin/viewvc.cgi/trunk/rtl/unix/cthreads.pp?view=markup#l339

This is a bit of a pain, since I can easily set the main thread scheduling parameters by using command line options to `start-stop-daemon` or `chrt`, but then need to use pthread_setschedparam() manually for each thread I create.

Henry

No particular reason. Probably because it tries to mimic windows behaviour.

Michael.

I thought Windows threads always start with the same priority as the process?

I also just noticed that this code probably leaks memory, since pthread_attr_destroy() is never called for thread_attr.

Henry

http://svn.freepascal.org/cgi-bin/viewvc.cgi/trunk/rtl/unix/cthreads.pp?view=markup#l339

> > No particular reason. Probably because it tries to mimic windows

behaviour.

I thought Windows threads always start with the same priority as the process?

Yes and no. On windows processes have a process class and threads have a priority level. Threads inherit the priority class from the process (and this can not be changed on a per thread level) and are created with priority level THREAD_PRIORITY_NORMAL *within* that priority class. Changing the priority level then only changes the priority level *inside* the priority class.
Don't know how good this Windows behavior is approximated on cthreads systems though... (and I don't really know wether it's good to approximate it :/ )

Regards,
Sven

OK, thanks. I can't think of a straight forward way to abstract the policies and priorities. Since it's quite a specialised thing to do and the policy/priority (at least on linux) depends on the system and what else is running on it, perhaps it's not unreasonable to let the user write platform specific code for their use case.

Not inheriting the policy/priority on linux is definitely unexpected, though, I only found out after reading the code in cthreads. Does anyone agree with me here? Shall I file a bug report?

I'll file a bug report for the leak.

Henry