Jan Kiszka wrote: >> Dirk Eibach wrote: >> I'm wondering how long a rt_mutex_acquire is supposed to take on a PPC405 >> platform. I'm getting times about 50 usec here, which is too much for my >> application. Is anything wrong in my kernel/xenomai configuration or is >> this time to expected? [...] > Still not really short, but it is a full syscall in the end. Anyone with > platform experience around to comment on the numbers?
My guess would be that rt_mutex_acquire always takes a syscall, regardless the state of the mutex. When the most common case is an unlocked mutex, this hurts on low end platforms. Reading the code, it looks like this is confirmed by src/skins/native/mutex.c, at least in version 2.3.2. I remember this issue was raised couple of month ago in this thread[1]. Xenomai needs an implementation of fast acquisition path for mutexes, along the principle of FUTEX but independent[2] from it. Maybe someone is already working it? [1] https://mail.gna.org/public/xenomai-help/2007-05/msg00105.html [2] https://mail.gna.org/public/xenomai-help/2007-05/msg00120.html Regards -- Stephane _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
