TLB shootdowns in /proc/interrupts (different results)

[Mulyadi Santosa]

Hi...

On Sat, Mar 9, 2013 at 4:04 PM, Kevin Wilson <wkevils at gmail.com> wrote:
> Hi,
> I have two x86_64 machines:
> On the first there is Fedora 18 (x86_64); on the second there is
> Ubunutu 12.10 (server, 64 bit).
>
> I run cat /proc/interrupts on both machines; in both cases, I run this command
> after an hour when the machine is up.
> I get:
> On the fedora machine
> cat /proc/interrupts | grep TLB
> TLB:          0          0   TLB shootdowns
> On the Ubuntu machine, however, there are many TLB shootdowns, on both
> cores.

That is a very interesting data....

btw, after quick check at
http://stackoverflow.com/questions/3748384/what-is-tlb-shootdown, I
conclude that likely Fedora 18 default kernel does something, that in
your workload prevent tlb shootdown. What can that be? IMHO, one high
possibility is preventing process rescheduling to another core(s)
and/or grouping all threads in same group in same core(s).

But I am not sure. That sounds like defeating the purpose of SMP.



-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com