rusage and pthreads

[Chuck Swiger]

On Jan 18, 2011, at 5:01 PM, Mark Terribile wrote:
> and continues further down
> 
>        ru = &td->td_ru;
>        ru->ru_ixrss += pgtok(vm->vm_tsize);
>        ru->ru_idrss += pgtok(vm->vm_dsize);
>        ru->ru_isrss += pgtok(vm->vm_ssize);
> 
> This looks to me like it's accumulating the data in per-thread counters.  What's more, it's consistent with what I'm seeing on the user side.  Note that this is 7.2; if 8.x behaves differently I'd like to know.


I wonder if all of the threads in a process might be pointing to the same struct rusage?

Nope, checking kern/kern_resource.c kern_getrusage(), there is a per-proc struct rusage_ext which gets the sum of the per-thread td->td_ru counters via rufetch() / ruxagg()...so you're right that the counters are now per-thread.

> Which would mean that a process that is occupying memory but doesn't happen to be running on that clock tick doesn't have its memory counted toward the total ... right?

That's right.

Regards,
-- 
-Chuck