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

[Ingo Molnar <mingo@elte.hu>]

* 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