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SubjectRe: [PATCH 00/10] x86: Reduce memory and intra-node effects with large count NR_CPUs

* travis@sgi.com <travis@sgi.com> wrote:

> This patchset addresses the kernel bloat that occurs when NR_CPUS is
> increased. The memory numbers below are with NR_CPUS = 1024 which I've
> been testing (4 and 32 real processors, the rest "possible" using the
> additional_cpus start option.) These changes are all specific to the
> x86 architecture, non-arch specific changes will follow.

thanks, i'll try this patchset in x86.git.

> 32cpus 1kcpus-before 1kcpus-after
> 7172678 Total +23314404 Total -147590 Total

1kcpus-after means it's +23314404-147590, i.e. +23166814? (i.e. a 0.6%
reduction of the bloat?)

i.e. we've got ~22K bloat per CPU - which is not bad, but because it's a
static component, it hurts smaller boxes. For distributors to enable
CONFIG_NR_CPU=1024 by default i guess that bloat has to drop below 1-2K
per CPU :-/ [that would still mean 1-2MB total bloat but that's much
more acceptable than 23MB]

Ingo


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