On Mon, Nov 12, 2018 at 08:54:12AM -0800, Daniel Jordan wrote:

On Sat, Nov 10, 2018 at 03:48:14AM +0000, Elliott, Robert (Persistent Memory) wrote:

quoted

quoted

-----Original Message-----
From: linux-kernel-owner@vger.kernel.org <linux-kernel-
owner@vger.kernel.org> On Behalf Of Daniel Jordan
Sent: Monday, November 05, 2018 10:56 AM
Subject: [RFC PATCH v4 11/13] mm: parallelize deferred struct page
initialization within each node

...  The kernel doesn't
know the memory bandwidth of a given system to get the most efficient
number of threads, so there's some guesswork involved.  

The ACPI HMAT (Heterogeneous Memory Attribute Table) is designed to report
that kind of information, and could facilitate automatic tuning.

There was discussion last year about kernel support for it:
https://lore.kernel.org/lkml/20171214021019.13579-1-ross.zwisler@linux.intel.com/ (local)

Thanks for bringing this up.  I'm traveling but will take a closer look when I
get back.

So this series would give the total bandwidth for a memory target, but there's
not a way to map that to a CPU count.  In other words, it seems we couldn't
determine how many CPUs it takes to reach the max bandwidth.  If I haven't
missed something, I'm going to remove that comment.