Hi all,
This weekend I've discovered a (serious) kernel scheduling latency issue
with the current ieee1394 kernel drivers. Before I submit something
about this to lkml, I'd like some more tests. I've been able to
reproduce this on two different machines, so I suspect that this is a
more general problem.
The problem summary is that running ieee1394 ISO traffic can cause
scheduling latency spikes up to 1ms, even for RT threads with higher
priority.
I've written a simple test suite that can be used to reproduce this
behavior. The only thing needed is a firewire host controller (no
firewire devices). I'd appreciate it if some people would try the test
so that I can have an overview of the problem. Of course, this applies
mostly to people running an -RT patched kernel.
You can find the test suite here:
http://freebob.sourceforge.net/old/ieee1394-latencytest.tar.gz
see the README for details.
Please report the maximum latency you get and the kernel/hardware you're
running.
Many thanks,
Pieter Palmers
FreeBoB developer
