On 2016-11-02 18:47:49 [-0400], Charles (Chas) Williams wrote:
> I don't this this is a race. Here is some debugging from the two CPU VM
> (2 sockets, 1 core per socket). In identify_cpu() we have:
>
> /* The boot/hotplug time assigment got cleared, restore it */
> c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
>
> The values just after this:
>
> [ 0.228306] identify_cpu: c ffff88023fd0a040 logical_proc_id 65535
> c->phys_proc_id 2
>
> So what's interesting here, is the phys_proc_id of 2 for CPU1:
>
> int topology_phys_to_logical_pkg(unsigned int phys_pkg)
> {
> if (phys_pkg >= max_physical_pkg_id)
> return -1;
> return physical_to_logical_pkg[phys_pkg];
> }
>
> And we happen to know the max_physical_pkg_id is 2 in this case.
> So apparently, topology_phys_to_logical_pkg() returns -1 and it gets
> assigned to the logical_proc_id.
>
> I don't know why the CPU's phys_proc_id is 2.
This is the physical ID. You have two logical IDs (on your two sockets
machine). What is max_physical_pkg_id? In order to get that -1 you would
have to max_physical_pkg_id of 1 but code does
max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
and I would be a little surprised if this is 1.
Sebastian
