[ltp] Re: Ubuntu 32 vrs 64 bit

Daniel Castro linux-thinkpad@linux-thinkpad.org
Tue, 16 Dec 2008 09:28:15 +0000


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thank you all! 32 bit on my laptop it is!

2008/12/15 Christoph Bier <christoph.bier@web.de>

> Micha Feigin schrieb am 15.12.2008 19:11:
>
> > On Mon, 15 Dec 2008 16:49:50 +0100
> > "Adrian Bastholm" <adrian@javaguru.org> wrote:
> >
> >> The PAE enabled "bigmem" kernels, can they make use of memory which is
> >> "appropriated" (or in english, made unavailable, stolen) by certain
> >> motherboards ?
> >>
> >> Adrian
> >>
> >> >
> >> > As Daniel uses Ubuntu he just can choose Ubuntu's server kernel that
> >> > has already enabled PAE. That's the way I address 4 GB of RAM on my
> >> > X200s with Ubuntu 8.10.
> >> >
> >
> > But here you start paying all sorts of penaltries that usually justify
> moving
> > to a 64bit system. This kernel is more appropriate to 32bit cpus using
> more
> > than 2/3 GB ram, not for 64bit cpus.
> >
> > First of all you can access more than 2 or 3 GB for each process (the
> process
> > memory space is limited to 4GB out of which 1 or 2 GB depending on kernel
> setup
> > are reserved for the kernel). (this also applies to swap usage with
> system with
> > 2GB memory of less)
> >
> > Second problem is that you hit an overhead when accessing this extra
> memory.
> >
> > What you are better off doing is running a 64bit kernel and a 32bit
> userspace
> > if  you want the 32bit userspace and to be able to use the extra memory
> (you
> > are still stuck with the maximum 2GB memory per process though) core2 and
> amd
> > 64bit run the 32bit processes nativelly and not in emulation mode so you
> don't
> > get the performance hit there (unlike ia64)
>
> Thanks for your explanation! I did not know about that.
>
> Best
> Christoph
> --
> +++ Typografie-Regeln: http://zvisionwelt.de/downloads.html (1.6)
>
> --
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
>
>


-- 
________________________

Daniel Castro, M.Sc.
+353 083-318-2058
dancasmo@gmail.com
castromd@tcd.ie
________________________

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thank you all! 32 bit on my laptop it is!<br><br><div class="gmail_quote">2008/12/15 Christoph Bier <span dir="ltr">&lt;<a href="mailto:christoph.bier@web.de">christoph.bier@web.de</a>&gt;</span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Micha Feigin schrieb am 15.12.2008 19:11:<br>
<div class="Ih2E3d"><br>
&gt; On Mon, 15 Dec 2008 16:49:50 +0100<br>
&gt; &quot;Adrian Bastholm&quot; &lt;<a href="mailto:adrian@javaguru.org">adrian@javaguru.org</a>&gt; wrote:<br>
&gt;<br>
&gt;&gt; The PAE enabled &quot;bigmem&quot; kernels, can they make use of memory which is<br>
&gt;&gt; &quot;appropriated&quot; (or in english, made unavailable, stolen) by certain<br>
&gt;&gt; motherboards ?<br>
&gt;&gt;<br>
&gt;&gt; Adrian<br>
&gt;&gt;<br>
&gt;&gt; &gt;<br>
&gt;&gt; &gt; As Daniel uses Ubuntu he just can choose Ubuntu&#39;s server kernel that<br>
&gt;&gt; &gt; has already enabled PAE. That&#39;s the way I address 4 GB of RAM on my<br>
&gt;&gt; &gt; X200s with Ubuntu 8.10.<br>
&gt;&gt; &gt;<br>
&gt;<br>
&gt; But here you start paying all sorts of penaltries that usually justify moving<br>
&gt; to a 64bit system. This kernel is more appropriate to 32bit cpus using more<br>
&gt; than 2/3 GB ram, not for 64bit cpus.<br>
&gt;<br>
&gt; First of all you can access more than 2 or 3 GB for each process (the process<br>
&gt; memory space is limited to 4GB out of which 1 or 2 GB depending on kernel setup<br>
&gt; are reserved for the kernel). (this also applies to swap usage with system with<br>
&gt; 2GB memory of less)<br>
&gt;<br>
&gt; Second problem is that you hit an overhead when accessing this extra memory.<br>
&gt;<br>
&gt; What you are better off doing is running a 64bit kernel and a 32bit userspace<br>
&gt; if &nbsp;you want the 32bit userspace and to be able to use the extra memory (you<br>
&gt; are still stuck with the maximum 2GB memory per process though) core2 and amd<br>
&gt; 64bit run the 32bit processes nativelly and not in emulation mode so you don&#39;t<br>
&gt; get the performance hit there (unlike ia64)<br>
<br>
</div>Thanks for your explanation! I did not know about that.<br>
<div><div></div><div class="Wj3C7c"><br>
Best<br>
Christoph<br>
--<br>
+++ Typografie-Regeln: <a href="http://zvisionwelt.de/downloads.html" target="_blank">http://zvisionwelt.de/downloads.html</a> (1.6)<br>
<br>
--<br>
The linux-thinkpad mailing list home page is at:<br>
<a href="http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad" target="_blank">http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad</a><br>
<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>________________________<br><br>Daniel Castro, M.Sc.<br>+353 083-318-2058<br><a href="mailto:dancasmo@gmail.com">dancasmo@gmail.com</a><br><a href="mailto:castromd@tcd.ie">castromd@tcd.ie</a><br>
________________________<br>

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