From: Matthew Wilcox <willy@infradead.org>
To: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, "Anaczkowski,
Lukasz" <lukasz.anaczkowski@intel.com>,
"Box, David E" <david.e.box@intel.com>,
"Kogut, Jaroslaw" <Jaroslaw.Kogut@intel.com>,
"Koss, Marcin" <marcin.koss@intel.com>,
"Koziej, Artur" <artur.koziej@intel.com>,
"Lahtinen, Joonas" <joonas.lahtinen@intel.com>,
"Moore, Robert" <robert.moore@intel.com>,
"Nachimuthu, Murugasamy" <murugasamy.nachimuthu@intel.com>,
"Odzioba, Lukasz" <lukasz.odzioba@intel.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Schmauss, Erik" <erik.schmauss@intel.com>,
"Verma, Vishal L" <vishal.l.verma@intel.com>,
"Zheng, Lv" <lv.zheng@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Balbir Singh <bsingharora@gmail.com>,
Brice Goglin <brice.goglin@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Jerome Glisse <jglisse@redhat.com>,
John Hubbard <jhubbard@nvidia.com>, Len Brown <lenb@kernel.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
devel@acpica.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org,
linux-nvdimm@lists.01.org, linux-api@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 0/3] create sysfs representation of ACPI HMAT
Date: Wed, 20 Dec 2017 10:19:37 -0800 [thread overview]
Message-ID: <20171220181937.GB12236@bombadil.infradead.org> (raw)
In-Reply-To: <20171218203547.GA2366@linux.intel.com>
On Mon, Dec 18, 2017 at 01:35:47PM -0700, Ross Zwisler wrote:
> What I'm hoping to do with this series is to just provide a sysfs
> representation of the HMAT so that applications can know which NUMA nodes to
> select with existing utilities like numactl. This series does not currently
> alter any kernel behavior, it only provides a sysfs interface.
>
> Say for example you had a system with some high bandwidth memory (HBM), and
> you wanted to use it for a specific application. You could use the sysfs
> representation of the HMAT to figure out which memory target held your HBM.
> You could do this by looking at the local bandwidth values for the various
> memory targets, so:
>
> # grep . /sys/devices/system/hmat/mem_tgt*/local_init/write_bw_MBps
> /sys/devices/system/hmat/mem_tgt2/local_init/write_bw_MBps:81920
> /sys/devices/system/hmat/mem_tgt3/local_init/write_bw_MBps:40960
> /sys/devices/system/hmat/mem_tgt4/local_init/write_bw_MBps:40960
> /sys/devices/system/hmat/mem_tgt5/local_init/write_bw_MBps:40960
>
> and look for the one that corresponds to your HBM speed. (These numbers are
> made up, but you get the idea.)
Presumably ACPI-based platforms will not be the only ones who have the
ability to expose different bandwidth memories in the future. I think
we need a platform-agnostic way ... right, PowerPC people?
I don't know what the right interface is, but my laptop has a set of
/sys/devices/system/memory/memoryN/ directories. Perhaps this is the
right place to expose write_bw (etc).
> Once you know the NUMA node of your HBM, you can figure out the NUMA node of
> it's local initiator:
>
> # ls -d /sys/devices/system/hmat/mem_tgt2/local_init/mem_init*
> /sys/devices/system/hmat/mem_tgt2/local_init/mem_init0
>
> So, in our made-up example our HBM is located in numa node 2, and the local
> CPU for that HBM is at numa node 0.
initiator is a CPU? I'd have expected you to expose a memory controller
abstraction rather than re-use storage terminology.
next prev parent reply other threads:[~2017-12-20 18:19 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-14 2:10 [PATCH v3 0/3] create sysfs representation of ACPI HMAT Ross Zwisler
2017-12-14 2:10 ` [PATCH v3 1/3] acpi: HMAT support in acpi_parse_entries_array() Ross Zwisler
2017-12-15 0:49 ` Rafael J. Wysocki
2017-12-15 1:10 ` Dan Williams
2017-12-16 1:53 ` Rafael J. Wysocki
2017-12-16 1:57 ` Dan Williams
2017-12-16 2:15 ` Rafael J. Wysocki
2017-12-14 2:10 ` [PATCH v3 2/3] hmat: add heterogeneous memory sysfs support Ross Zwisler
2017-12-15 0:52 ` Rafael J. Wysocki
2017-12-15 20:53 ` Ross Zwisler
2017-12-14 2:10 ` [PATCH v3 3/3] hmat: add performance attributes Ross Zwisler
2017-12-14 13:00 ` [PATCH v3 0/3] create sysfs representation of ACPI HMAT Michal Hocko
2017-12-18 20:35 ` Ross Zwisler
2017-12-20 16:41 ` Ross Zwisler
2017-12-21 13:18 ` Michal Hocko
2017-12-20 18:19 ` Matthew Wilcox [this message]
2017-12-20 20:22 ` Dave Hansen
2017-12-20 21:16 ` Matthew Wilcox
2017-12-20 21:24 ` Ross Zwisler
2017-12-20 22:29 ` Dan Williams
2017-12-20 22:41 ` Ross Zwisler
2017-12-21 20:31 ` Brice Goglin
2017-12-22 22:53 ` Dan Williams
2017-12-22 23:22 ` Ross Zwisler
2017-12-22 23:57 ` Dan Williams
2017-12-23 1:14 ` Rafael J. Wysocki
2017-12-27 9:10 ` Brice Goglin
2017-12-30 6:58 ` Matthew Wilcox
2017-12-30 9:19 ` Brice Goglin
2017-12-20 21:13 ` Ross Zwisler
2017-12-21 1:41 ` Elliott, Robert (Persistent Memory)
2017-12-22 21:46 ` Ross Zwisler
2017-12-21 12:50 ` Michael Ellerman
2017-12-22 3:09 ` Anshuman Khandual
2017-12-22 10:31 ` Kogut, Jaroslaw
2017-12-22 14:37 ` Anshuman Khandual
2017-12-22 17:13 ` Dave Hansen
2017-12-23 5:14 ` Anshuman Khandual
2017-12-22 22:13 ` Ross Zwisler
2017-12-23 6:56 ` Anshuman Khandual
2017-12-22 22:31 ` Ross Zwisler
2017-12-25 2:05 ` Liubo(OS Lab)
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