Best way to use more that 4 gigs of memory ?
Bob Bishop
rb at gid.co.uk
Sun Nov 4 14:39:29 PST 2007
Hi,
On 4 Nov 2007, at 21:11, Pete French wrote:
> I have been doing some experiments with runnign 32 bit processed on
> and amd64 kernel over the last couple of days and am wondering what
> the general feel is for the best way to use over 4 gigs of memory.
> As far
> as I can see I have 3 options:
>
> 1) amd64 kernel + 64 bit processes
> 2) amd64 kernel + 32 bit processes
> 3) i386 kernel with PAE and 32 bit processes
>
> I was initially thinking that option 1 was the best, but
> benchmarking it
> the programs take 3 times longer to run that option 2! This
> astounds me
> and I intend to investigate why, but given it is rue then that
> rules it out
> as a viable solution for deploying stuff.
I had similar results, I surmise (without evidence) it's to do with
cache usage.
> Which leaves either 32 bit processes on a 64 bit kernel or
> alternatively
> running under PAE on a 32 bit kerenel. I don't know a lot about PAE
> and
> was wondering if anyone had any advice either way as to which
> wouldbe the most
> stable and/or best performing.
If your workload is CPU-intensive it probably doesn't matter; if it
isn't, I'd do some more experiments.
> cheers,
>
> -pcf.
--
Bob Bishop +44 (0)118 940 1243
rb at gid.co.uk fax +44 (0)118 940 1295
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