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From: Brian Gerst <bgerst@didntduck.org>
To: Peter Zaitsev <pz@spylog.ru>
Cc: Linux Kernel List <linux-kernel@vger.kernel.org>
Subject: Re: 3.5G user space speed
Date: Tue, 15 Jan 2002 16:05:39 -0500	[thread overview]
Message-ID: <3C4499A3.781E5A85@didntduck.org> (raw)
In-Reply-To: <16247691406.20020115234737@spylog.ru>

Peter Zaitsev wrote:
> 
> Hello Linux,
> 
>   2.4.xaa Series as well as  SuSE kernels have  3.5G userspace option,
>   which seems to be quite useful, therefore I see it's not included
>   is stock kernel for some reasons. Also I've heard this
>   configuration may have some performance problems.
> 
>   Can anyone comment on this topic ?
> 
>   I need large amount of address space for my application but I also
>   need to get as much I/O performance as it's possible, so I can switch
>   to 3.0/1.0 memory distribution if it will benefit here.

You can't have it both ways with the x86 (speed vs. large userspace). 
Kernel 2.5 may help a bit here because changes were made to allow DMA
from all memory (subject to card limitations), lessening the burden for
direct-mapped memory.  Otherwise you'll need to move to a 64-bit arch.

--

				Brian Gerst

  reply	other threads:[~2002-01-15 21:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-15 20:47 3.5G user space speed Peter Zaitsev
2002-01-15 21:05 ` Brian Gerst [this message]
2002-01-15 21:28   ` Re[2]: " Peter Zaitsev
2002-01-15 21:41     ` Brian Gerst
2002-01-15 21:49       ` Re[2]: " Peter Zaitsev
2002-01-15 22:09 ` H. Peter Anvin

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