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From: Michael Ellerman <mpe@ellerman.id.au>
To: Matthew Wilcox <willy@infradead.org>,
	Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>, "Box\,
	David E" <david.e.box@intel.com>,
	Dave Hansen <dave.hansen@intel.com>, "Zheng\,
	Lv" <lv.zheng@intel.com>, linux-nvdimm@lists.01.org, "Verma\,
	Vishal L" <vishal.l.verma@intel.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, "Anaczkowski\,
	Lukasz" <lukasz.anaczkowski@intel.com>, "Moore\,
	Robert" <robert.moore@intel.com>,
	linux-acpi@vger.kernel.org, "Odzioba\,
	Lukasz" <lukasz.odzioba@intel.com>, "Schmauss\,
	Erik" <erik.schmauss@intel.com>, Len Brown <lenb@kernel.org>,
	John Hubbard <jhubbard@nvidia.com>,
	linuxppc-dev@lists.ozlabs.org, Jerome Glisse <jglisse@redhat.com>,
	Dan Williams <dan.j.williams@intel.com>,
	devel@acpica.org, "Kogut\, Jaroslaw" <Jaroslaw.Kogut@intel.com>,
	linux-mm@kvack.org, "Koss\, Marcin" <marcin.koss@intel.com>,
	linux-api@vger.kernel.org, Brice Goglin <brice.goglin@gmail.com>,
	"Nachimuthu\, Murugasamy" <murugasamy.nachimuthu@intel.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org, "Koziej\,
	Artur" <artur.koziej@intel.com>, "Lahtinen\,
	Joonas" <joonas.lahtinen@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH v3 0/3] create sysfs representation of ACPI HMAT
Date: Thu, 21 Dec 2017 23:50:40 +1100
Message-ID: <87mv2cfdnj.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <20171220181937.GB12236@bombadil.infradead.org>

Matthew Wilcox <willy@infradead.org> writes:

> 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?

Yes!

I don't have any detail at hand but will try and rustle something up.

cheers

  parent reply index

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-14  2:10 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
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 [this message]
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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