Re: Ubuntu 32-bit, 32-bit PAE, 64-bit Kernel Benchmarks

From: Sitsofe Wheeler
Date: Sat Jan 16 2010 - 07:33:38 EST

On Fri, Jan 15, 2010 at 05:49:06PM -0800, H. Peter Anvin wrote:
> On 12/30/2009 05:29 PM, Yuhong Bao wrote:
> >
> > Given that Linus was once talking about the performance penalties of
> > PAE and HIGHMEM64G, perhaps you'd find these benchmarks done by
> > Phoronix of interest:
> >
> >
> The big difference isn't between HIGHMEM4G (no PAE) and HIGHMEM64G
> (PAE), it's between HIGHMEM and !HIGHMEM. That cutoff is ~892 MB for a
> stock 32-bit kernel.

Thanks for the clarification - I had been wondering about why those
settings had been benchmarked against each other...

I took a mild interest because I have an EeePC 900 with 1G of RAM. The
machine can do PAE but my understanding is that this would lead to a
performance drop (I currently have VMSPLIT_3G so I can use all 1G of
memory) so I run it without HIGHMEM.

Sitsofe |
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