[OpenIndiana-discuss] Tribblix update

[Moinak Ghosh]

On Mon, Dec 17, 2012 at 11:22 PM, Alan Coopersmith <
alan.coopersmith at oracle.com> wrote:

> On 12/17/12 03:41 AM, Jim Klimov wrote:
> > On 2012-12-17 06:59, Alan Coopersmith wrote:
> >> Oh, and it assumes no one needs 32-bit binaries any more, since all
> Solaris 11
> >> users have to be running the 64-bit kernel since the 32-bit kernel was
> EOL'ed.
> >> (32-bit libraries are still there for binary compatibility with other
> programs,
> >>   it's just most of the /usr/bin/x* commands converted to 64-bit.)
> >>
> >> If you care about 32-bit support, that's one more change you'll have to
> undo.
> >
> > Well, I may probably get corrected (and should, if need be) - but
> > in such discussions I've always thought (and heard) that these are
> > two different things. 64-bit kernel is for optimal harnessing of
> > hardware with large (>4gb) memory and perhaps wider instructions
> > on CPU.
> >
> > 64-bit or 32-bit userspace programs is about addressing virtual
> > memory again and large files to an extent (AFAIK the latter can
> > be used with 32-bit programs too). 64-bit userspace with "small"
> > programs like many UNIX command-line tools, GUI applets, etc.
> > which don't feasibly need to juggle gigabytes of data at once -
> > now, that would also be about wasting RAM and CPU cycles on
> > pushing around more bytes of pointers and other increased
> > structures with no practical gain.
> >
> > Am I wrong to maintain this point of view?
>
> That's mostly correct, but there are other benefits to 64-bit userspace
> programs:
>
>  - stdio interfaces in libc support file descriptors > 255 without any
>    compatibility issues or interface extensions
>
>  - x86 binaries have access to a larger number of registers, often
> resulting
>    in measurably faster performance
>

Typically true but the new 32-bit ABI changes all that:
https://sites.google.com/site/x32abi/
http://en.wikipedia.org/wiki/X32_ABI

If Solaris integrates support for this then 32-bit having less pointer
overhead
compared to 64-bit will continue to hold on x86. However IMHO for a typical
large application (as opposed to small utilities), clean support for large
files,
and no practical heap limitations make 32-bit forgettable.

Regards,
Moinak.
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