Re: numastats updates

On Mon, 7 Apr 2014, Andi Kleen wrote:

> >   * starts a binary with the specified numa memory policy using
> > numactl (or a like):
> >     numactl --interleave=all get_some_memory_with_malloc_and_write_it
> >   * `sleep` for few seconds
> >   * numastat > /tmp/after
> >   * compares /tmp/before and /tmp/after to check that the numa policy
> > was applied the right way
> >
> > But the problem is that on a host with many NUMA nodes (8) the process
> > of updating that numastats statistics takes some time. Even 10 seconds
> > may be not enough. Therefore the test fails.
> >
> > Is there a direct or indirect way to force the kernel to update the
> > NUMA statistics?
>
> Not currently. It depends on how much memory you have and subsequent
> operations. I guess would need to add one.

The kernel vm statistics are brought up to date with the default
settings every 2 seconds.

The interval is controlled via /proc/sys/vm/stat_interval

Check the value that you have setup there.