On Thu, 28 Jan 2010 16:54:24 +0200
Török Edwin <edwinto...@gmail.com> articulated:
> On 01/28/2010 04:03 PM, Jerry wrote:
> > On Thu, 28 Jan 2010 15:19:47 +0200
> > Török Edwin <edwinto...@gmail.com> articulated:
> >
> >
> >> On 01/28/2010 02:40 PM, Jerry wrote:
> >>
> >>> I was wondering if 'clamav' is a true 64-bit program
> >>>
> >> Please be more explicit. What Operating System are we talking
> >> about?
> >
> > The OS is FreeBSD. I presently have a 32-bit system; however, I
> > will be upgrading to a full 64-bit system.
> >
>
> ClamAV is developed and tested mostly on Linux/x86_64.
> So yes, building it as a 64-bit application is supported.
>
> >
> >>> or simply one that
> >>> runs on both 32 & 64 bit operating systems.
> >>>
> >> It can be compiled both as both a 32-bit and a 64-bit binary.
> >>
> >
> > I realize that it can run on both systems, many software packages do
> > that. However, extremely few take full advantage of the 64-bit
> > architecture. I was just wondering if Clamav did.
>
> It is important the compiler is able to compile/optimize for the
> 64-bit CPU. Then ALL applications will take advantage of your CPU's
> features.
>
> There are 4 important aspects about a 64-bit system IMHO:
> 1. Able to access/allocate more than 4GB of files/memory
> This is useful for databases for example, but not for ClamAV (we
> don't scan files that large, and it doesn't need 4G of memory to run)
> This is actually a disadvantage for ClamAV, since pointers take up
> more space, and thus the memory used by the database is higher than
> on 32-bit.
>
> 2. All amd64 CPUs support at least SSE2
> Compilers will by default optimize for that.
> On 32-bit systems your OS is built for i486, i686, which doesn't use
> all the optimizations for your CPU (unless you run gentoo and rebuild
> everything).
>
> So if you build ClamAV without any special optimization flags it
> should be faster on 64-bit than 32-bit!
> Of course you can get same result on 32-bit by using -march=native,
> but thats not the default.
>
> 3. amd64 instruction set has more registers, and 64-bit registers
> 8 more registers means more efficient code, without the need to often
> spill/reload from the stack when you run out of registers (as you
> often do on 32-bit)
> 64-bit register means the compiler can more efficiently implement some
> operations.
>
> 4. The amd64 calling convention passes parameters in registers by
> default, and not on the stack (uses the stack only if registers are
> not enough).
> Which means that function call overhead is smaller.
>
>
> > Adobe, and a few
> > Microsoft products were the only ones that I was aware of that did.
> >
>
> Maybe if you are thinking of windows applications, which is a
> completely different matter than
> FreeBSD applications.
Thank you. That is what I wanted to know.
--
Jerry
ges...@yahoo.com
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A prig is a fellow who is always making you a present of his opinions.
George Eliot
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