Re: Mixed 64-bit system GerH binaries / BillYscripts

@Paolo asking for performance metrics regarding 64/32:

I don't have performance metrics comparing 64 vs. 32. haven't tested
performance numbers yet. Don't expect huge gains. CRM114 isn't limited
much by 32-bit int or other bit boundaries (though 'float' is a hazard
for me, but then I moved the code to 'double' and that was that.
Besides, given the number of floatring point ops and modern hardware,
there's no compelling reason yet for me to 'tweak it' into consistent
float for perfomance reasons alone. You'll need to ditch the C fp
run-time lib then too, anyway. (See 3D fp-intensive game engines:
float all over, and close to zero run-time lib usage and torrents of
custom optimizations in that area as well.)


Wet finger in wind guestimate tells me memory mapped I/O is more
significant, so 64-bit is only really important for the natives and
those that intend to use _huge_ wordsets (= CSS files) -- like me.
Tweaking the disc I/O for ultrafast CSS read/write plus optimizing the
storage for CPU caches is first.


Best thing I can say now is: make sure your 64-bit works because few
are willing to 'cross-compile' to 32-bit when they have the iron for
64. Besides, you shouldn't think of it as a 'bother' but rather a neat
way to check your code for anomalies; I've always liked to build on
multiplatform because there's nothing like a multiple compiler /
platform environment to kick up shit when you didn't really work out
your algorithms' implementation all that well: it'll bust a lot of
your _implicit_ assumptions in no time and from 20 years in the biz I
can say that _implicit_ assumptions are always the one that kill you
(a.k.a. me) _hard_ in production, when you've no way to shut down that
24/7 system and the bugs are such that you should and need.

Sorry. I'm off.

Ger





On Fri, Aug 29, 2008 at 3:40 PM, Paolo <[email protected]> wrote:
> On Fri, Aug 29, 2008 at 03:07:56PM +0200, Thomas Spahni wrote:
>>
>> My HW supplier doesn't sell 32-bit cpu's any more. That's the only reason
>> why I switched to 64-bit.
>
> hm, unless your system is IA64, you can run a 32bit system on x86_64 with
> no problem. For non-x86* dunno though.
>
>> As for performance: 64-bit is definitely SLOWER for most apps including
>> crm114. But it is difficult to compare. My old 32-bit system has a Pentium
>
> sure, but I meant comparison of 32 vs 64 OS+apps on _same_ hw (assuming
> of course 32/64 compatibility).
>
>
> thx
> --
>  paolo
>
>
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-- 
Met vriendelijke groeten / Best regards,

Ger Hobbelt

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