Gang scheduling implementation in the ULE scheduler

[Stefan Andritoiu]

Hi Peter,
Yes, I think it is lightly loaded. I am trying to run a FreeBSD guest
with 2 VCPUs on a 4 CPU host, with no other program running.
But I am having the same problem even when I start a 1 VCPU guest.

later,
Stefan

On Wed, Jun 10, 2015 at 11:40 PM, Peter Grehan <grehan at freebsd.org> wrote:
> Hi Stefan,
>
>> When I start a Virtual Machine, during the guest's boot, IPIs are sent
>> and received correctly between CPUs, but after a few seconds I get:
>>      spin lock 0xffffffff8164c290 (smp rendezvous) held by
>> 0xfffff8000296c000 (tid 100009) too long
>>      panic: spin lock held too long
>
>
>  Is this on a lightly loaded machine ? I've not looked at your diff in
> detail but it's possibly a code path where a spinlock wasn't unlocked,
> leaving another CPU spinning.
>
> later,
>
> Peter.
>