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    SubjectRe: [Lse-tech] [PATCH] cpusets - big numa cpu and memory placement
    On Friday 08 October 2004 11:53, Nick Piggin wrote:
    > Erich Focht wrote:
    > > On Thursday 07 October 2004 20:13, Martin J. Bligh wrote:
    > >
    > >>It all just seems like a lot of complexity for a fairly obscure set of
    > >>requirements for a very limited group of users, to be honest. Some bits
    > >>(eg partitioning system resources hard in exclusive sets) would seem likely
    > >>to be used by a much broader audience, and thus are rather more attractive.
    > >
    > > May I translate the first sentence to: the requirements and usage
    > > models described by Paul (SGI), Simon (Bull) and myself (NEC) are
    > > "fairly obscure" and the group of users addressed (those mainly
    > > running high performance computing (AKA HPC) applications) is "very
    > > limited"? If this is what you want to say then it's you whose view is
    > > very limited. Maybe I'm wrong with what you really wanted to say but I
    > > remember similar arguing from your side when discussing benchmark
    > > results in the context of the node affine scheduler.
    > >
    > > This "very limited group of users" (small part of them listed in
    > > is who drives computer technology, processor design,
    > > network interconnect technology forward since the 1950s.

    > With all due respect, Linux gets driven as much from the bottom up
    > as it does from the top down I think. Compared to desktop and small
    > servers, yes you are obscure :)

    I wasn't speaking of driving the Linux development, I was speaking of
    driving the computer technology development. Just look at where the
    DOD, DARPA, DOE money goes to. I actually aknowledged that HPC doesn't
    really have a foot in the kernel developer community.

    > My view on it is this, we can do *exclusive* dynamic partitioning
    > today (we're very close to it - it wouldn't add complexity in the
    > scheduler to support it).

    Right, but that's an implementation question. The question
    cpusets {AND, OR, XOR} CKRM ?
    was basically a user space API question. I'm sure nobody will object
    to changing the guts of cpusets to use sched_domains on exclusive sets
    when this possibility will be there and ... simple.
    > You can also hack up a fair bit of other functionality with cpu
    > affinity masks.

    I'm doing that for a subset of cpusets functionality in a module
    (i.e. without touching the task structure and without hooking on
    fork/exec) but that's ugly and on the long term insufficient.


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