Hi,

We have configured Linux 3.5.7 / Xenomai 2.6.2.1 on an MSI-7514 mainboard
with a Core 2 Duo CPU.

This configuration suffers from excessive worst-case latencies during the
'latency' test (on average: 2.6 µs, worst-case around 1900 µs, around 10
overruns per second). I believe these overruns are due to the CPUs entering
SM mode (SMI). As soon as the ACPI BIOS SMI is disabled (when
xeno_nucleus/native are loaded as a module), the computer shuts down in 5
secs. or so. Presumably some power supply watchdog on the mainboard isn't
triggered.

- Has someone also observed this behaviour and maybe solved it in some way ?
- I looked around in the Intel manuals and I don't think it's possible to
have only 1 CPU handle these SMIs. Is that correct ? If it were possible,
we could run RT tasks on the other one, obviously, but currently latency
shows overruns on both CPUs.
- Would it somehow be possible/sensible to leave the SMI disabled and
generically call the SMI handler directly from within (a task in) the OS ?
There's probably going to be issues, the least of which would be proper
handling of the RSM instruction outside SM mode. But still...


Jeroen.
_______________________________________________
Xenomai mailing list
[email protected]
http://www.xenomai.org/mailman/listinfo/xenomai

Reply via email to