lkml.org 
[lkml]   [2017]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v3 0/3] create sysfs representation of ACPI HMAT
Date
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

\
 
 \ /
  Last update: 2017-12-21 13:51    [W:0.164 / U:0.232 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site