lkml.org 
[lkml]   [2022]   [Oct]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [RFC] memory tiering: use small chunk size and more tiers
Date
Bharata B Rao <bharata@amd.com> writes:

> On 10/28/2022 11:16 AM, Huang, Ying wrote:
>> If my understanding were correct, you think the latency / bandwidth of
>> these NUMA nodes will near each other, but may be different.
>>
>> Even if the latency / bandwidth of these NUMA nodes isn't exactly same,
>> we should deal with that in memory types instead of memory tiers.
>> There's only one abstract distance for each memory type.
>>
>> So, I still believe we will not have many memory tiers with my proposal.
>>
>> I don't care too much about the exact number, but want to discuss some
>> general design choice,
>>
>> a) Avoid to group multiple memory types into one memory tier by default
>> at most times.
>
> Do you expect the abstract distances of two different types to be
> close enough in real life (like you showed in your example with
> CXL - 5000 and PMEM - 5100) that they will get assigned into same tier
> most times?
>
> Are you foreseeing that abstract distance that get mapped by sources
> like HMAT would run into this issue?

Only if we set abstract distance chunk size large. So, I think that
it's better to set chunk size as small as possible to avoid potential
issue. What is the downside to set the chunk size small?

Best Regards,
Huang, Ying

\
 
 \ /
  Last update: 2022-10-28 10:35    [W:1.010 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site