Re: [PATCH 2/2] mm/page_ref: add tracepoint to track down page reference manipulation

On Wed, Dec 09, 2015 at 10:36:48PM -0500, Steven Rostedt wrote:

On Thu, 10 Dec 2015 11:50:15 +0900
Joonsoo Kim [off-list ref] wrote:

quoted

Output of cpu 3, 7 are mixed and it's not easy to analyze it.

I think that it'd be better not to sort stack trace. How do
you think about it? Could you fix it, please?

It may not be that easy to fix because of the sorting algorithm. That
would require looking going ahead one more event each time and then
checking if its a stacktrace. I may look at it and see if I can come up
with something that's not too invasive in the algorithms.

Okay.

That said, for now you can use the --cpu option. I'm not sure I ever
documented it as it was originally added for debugging, but I use it
enough that it may be worth while to officially support it.

 trace-cmd report --cpu 3

Will show you just cpu 3 and nothing else. Which is what I use a lot.

Thanks for the input. It works but it's not sufficient to me.
Page reference is manipulated by multiple cpus so it's better to
analyze unified output.

But doing the stack trace thing may be something to fix as well. I'll
see what I can do, but no guarantees.

Okay. Don't be hurry. :)
trace-cmd is excellent and works well for me as it is.

Thanks.