[Beowulf] partitioning L3 by page coloring

Rayson Ho raysonlogin at gmail.com
Mon Apr 8 12:28:27 PDT 2013


I don't think it can be done if you are not changing the kernel page
allocator. Physical/virtual page mapping is all done by the kernel -
in the end, page faults are transparent in the userspace.

Even the traditional page coloring needs help from the kernel. There's
the "Compiler-directed page coloring for multiprocessors" work done by
Todd C. Mowry (another U of Toronto prof), but I don't recall seeing
any pure userspace page coloring techniques - and I would imagine it
is not entirely possible as the userspace doesn't know the physical
page address.

http://dl.acm.org/citation.cfm?id=237195

Rayson

==================================================
Open Grid Scheduler - The Official Open Source Grid Engine
http://gridscheduler.sourceforge.net/



On Mon, Apr 8, 2013 at 12:31 PM, Max R. Dechantsreiter
<max at performancejones.com> wrote:
> Rayson,
>
> ...In the paper you cited, I found the authors modified the
> Linux kernel page allocator: that approach seems far beyond
> what would be practical, or available to, a user not very
> sophisticated regarding kernel issues.  (Also, this must be
> hard to get correct!)
>
> I am not looking for the absolute best solution, if such
> exists; just a "quick and dirty" scheme I could use to test
> for benefit.
>
>
> Regards,
>
> Max
> ---
>
> On Mon, 8 Apr 2013, Rayson Ho wrote:
>
>> That technique was used in some of my U of Toronto friends' PhD thesis
>> research & projects:
>>
>> "Managing Shared L2 Caches on Multicore Systems in Software"
>>
>> "Reducing the Harmful Effects of Last-Level Cache Polluters with an
>> OS-Level, Software-Only Pollute Buffer"
>>
>> http://www.eecg.toronto.edu/~tamda/
>>
>> IIRC, all those techniques are OS only, with no changes to the CPU MMU
>> or cache mapping logic.
>>
>> Rayson
>>
>> ==================================================
>> Open Grid Scheduler - The Official Open Source Grid Engine
>> http://gridscheduler.sourceforge.net/
>>
>>
>>
>> On Sat, Apr 6, 2013 at 1:54 PM, Max R. Dechantsreiter
>> <max at performancejones.com> wrote:
>>>
>>>
>>> Would anyone with successful experience using this technique be willing
>>> to share details, and warn of pitfalls?
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>>
>


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