21 Jun
2006
21 Jun
'06
6:42 a.m.
Lee Revell wrote:
On Wed, 2006-06-21 at 00:21 +0200, Pieter Palmers
wrote:
I've tried using the latency tracer, but I was unable to get any other
results than the system timer (or what extactly was it called) at about
20us. Nothing from the ieee1394 stack showed up.
I probably need some usage explanation because the stuff I find googling
around seems to be out of date. Or at least it does not provide the info
I need to get usefull output. But that could be me.
Greets,
Pieter
BTW: should you have a firewire card, try it for yourself. After all,
that saves you the explanation, and I'm pretty confident that it will be
present on other machines too.
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.
Latency tracer output please?
Use 2.6.16 with this patch:
http://people.redhat.com/mingo/latency-tracing-patches/latency-tracing-v2.6…