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Date: Mon,  3 Nov 2008 16:55:31 +0100
From: Kernel Panic <cinap_lenrek@gmx.de>
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To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
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Subject: Re: [9fans] mmap and shared libraries
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dave.l@mac.com wrote:
> A thought ...
>
> Shared libraries do 2 possibly useful things:
> 1) save space
> 2) stop you having to re-link when a new library is released.
>
> Now 2) doesn't really happen anyway, due to .so versioning hell,
> so we're left with 1) ...
>
> I know it's kind-of hacky and unstructured (how do you know the venti
> block size?),
> but could you not block-align the library members in the .a,
> so venti would do the sharing on disk for you?

Look at this:
http://gsoc.cat-v.org/people/mjl/blog//2007-08-06-1_Rabin_fingerprints

> As a further step, you could also page align the text segments of the
> library members,
> then implement a venti-like scheme for read-only pages in memory,
> so that when the executable loads, it gets any common library pages
> shared.
>
> Dave.
>
> P.S. Sorry not to make Volos: where are the rest of the photos?
>