Re: Early hang with 2.6.21-rc4-rt1

[Roland Dreier]

 > I finally got curious enough to want to debug why starting kvm with
 > tun/tap networking produces a bunch of
 > 
 >     rtc: lost some interrupts at 1024Hz.
 > 
 > messages.  So I'm assuming it's a ~millisecond irqs-off section
 > somewhere.

And after everything, it's a heisenbug -- I repeatably get that lost
interrupts message on stock 2.6.21-rc4 but never on -rt1 with
CONFIG_LATENCY_TRACE.

Any suggestion of where to look?  My /proc/latency_trace stays
stubbornly empty -- are there any sysctls I need to change from their
default to get latency tracing?  I'm a complete noob when it comes to
the -rt patch, so I'm not sure what the right way to use the tracing
infrastructure to track down this lost rtc interrupts issue is.

Thanks, 
  Roland
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/