[PD] -rt for whom?

Tim Blechmann TimBlechmann at gmx.net
Tue Jul 6 12:42:46 CEST 2004

> SCHED_RR and SCHED_FIFO are close. I think the only difference is if
> the tasks have the same priority, then maybe SCHED_RR actually starts
> time-slicing.
> But don't take my work for it, look it up :-)
that's correct ... if there are two threads (a,b) with the same
priority, SCHED_FIFO will cause that the first of these thread will run
until it's finished or sleeping, then the second thread can start
(aaaaaabbbbbb). SCHED_RR will cause to run both threads for small
timeslices (ababababab)...
but afaik, it only has an effect if both threads are using the same
priority, so with pd, i don't know if there is an effect when using -rt.
if there are two threads, one having a high priority (reniced by -rt)
and one low priority there would be no difference ...
with a threaded pd (e.g. the devel_0_37) there would be effects. iirc,
the soundfiler thread and the gui thread are working in the same

another feature of the -rt mode is the memory locking ... it's enabled
on machines, where _POSIX_MEMLOCK is defined (at least on linux it is).
this will force the memory to be represented in the physical memory.
(one will not be able to allocate more memory). 

cheers ... tim

mailto:TimBlechmann at gmx.de    ICQ: 96771783

After one look at this planet any visitor from outer space 
would say "I want to see the manager."
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