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From: Eric Dumazet <dada1@cosmosbay.com>
To: regatta <regatta@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 32Bit vs 64Bit
Date: Wed, 16 Mar 2005 16:59:15 +0100	[thread overview]
Message-ID: <423857D3.80609@cosmosbay.com> (raw)
In-Reply-To: <5a3ed5650503160744730b7db4@mail.gmail.com>

regatta wrote:

> Hi everyone,
> 
> I have a question about the 64Bit mode in AMD 64bit
> 
> My question is if I run a 32Bit application in Optreon AMD 64Bit with
> Linux 64Bit does this give my any benefit ? I mean running 32Bit
> application in 64Bit machine with 64 Linux is it better that running
> it in 32Bit or doesn't make any different at all ?
> 
> Thanks

Hi

Running a 32 bits application on a x86_64 kernel gives more virtual 
address : 4GB of user memory, instead of 3GB on a standard 32bits kernel

If your application uses a lot of in-kernel ressources (like tcp 
sockets and network buffers), it also wont be constrained by the 
pressure a 32 bits kernel has on lowmem (typically 896 MB of lowmem)

If your machine has less than 2GB, running a 64bits kernel is not a 
win, because all kernel data use more ram (pointers are 64 bits 
instead of 32bits)

Eric


  reply	other threads:[~2005-03-16 15:59 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-16 15:44 32Bit vs 64Bit regatta
2005-03-16 15:59 ` Eric Dumazet [this message]
2005-03-16 16:40   ` regatta
2005-03-16 16:10 ` peto
2005-03-17 21:56 ` Helge Hafting
     [not found] <fa.d8o1hmd.1l3ipbn@ifi.uio.no>
     [not found] ` <fa.jg14340.1g0go0q@ifi.uio.no>
2005-03-18  5:02   ` Bodo Eggert

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