On 7/6/12 7:40 AM, Carsten Emde wrote:
Hi Dong,
I can quite reliably trigger this cpu stall error now. Just try to start
several KVM guests.
Good. BTW, we do repeated long-term tests 14 times per day with a single
kvm guest that runs on two cores and conducts a number of CPU
benchmarks. (https://www.osadl.org/?id=931) - never had this problem. So
it may be related to running more than a single kvm guest.
I'm using i7 860 with HT enabled. It has 8 logical cores. Maybe it has
something to do with it.
[..]
Are there any way I can use to narrow down this error?
cd /sys/kernel/debug/tracing/
echo 0 >tracing_on
echo 1 >events/enable
echo function >current_tracer
echo 14080 >buffer_size_kb
echo 1 >tracing_on
while true
do
if dmesg | tail -100 | grep -q "rcu_preempt detected stalls"
then
echo 0 >tracing_on
break
fi
sleep 1
done
I don't have /sys/kernel/debug/tracing/ directory. The kernel doc says
turn on CONFIG_KPROBE_TRACING. But I could not find this config.
Then start the kvm quests.
Alternatively, you may use the kernel parameter ftrace_dump_on_oops.
I'll try that.
Thanks,
Dong
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
