[padb-users] vmrss and vmlck question

[Daniel Kidger]

Duncan,

I tried a short piece of C code that calls mlock() with a user-adjustable
size, then sleeps.
Then I queried it using cat /proc/<pid>/status

In this case, it does appear that VmLck is a say a subset of VmRSS (and
VmSize for that matter)
If I increase the value in mlock() by say 128MB then both VmLck and VmRSS
both increase by this amount

Can you post an example where vmrss exceeds vmlck ?

Daniel



On 11 July 2011 14:06, Duncan Harris <harris.duncan at gmail.com> wrote:

> Hi.
> I have a question related to vmrss and vmlck (not technically a padb
> question I realise).
>
> We've modified our padb --proc-summary command to also print out the
> vmlck value. We did this as we were having a situation where one of
> our jobs was hitting the vmlck hardlimit on our machine and hanging as
> a result.
>
> However, we have a different code hanging now. Running padb shows that
> for one of the nodes (which has 12 cores) none of the vmlck values are
> hitting the limit, however if we sum the vmlck and vmrss values for
> the whole node, we do exceed the total memory available on the node
> (49 GB vs 48GB). Running a stack trace shows that 3 cores are stuck in
> an MPI_Wait_Some and 1 in a later MPI_Waitall. From the code all of
> the sends have been sent, so we've lost a message somewhere.
>
> My question is, how do the vmlck and vmrss values relate to each
> other? Should we be adding them together, or is the vmlck included in
> the vmrss value? We're assuming that they are separate as we have some
> cores where vmlck > vmrss.
>
> Thanks,
> Duncan
>
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