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Old 03-10-2009, 07:01 AM   #1
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Question /proc/cpuinfo explanations of cpu capabilities?

yes I googled for
cpuinfo pae sep nx
( 3 of the items I want to understand, before deciding on the virtual-machine settings I commit to in installing my video-editing system into it )

Specifically, changing VirtualBox to AMD-V or no AMD-V means these items exist ( in AMD-V ) or don't exist, as part of the CPU that the Guest sees.

I need to understand how they're going to affect the guest OS,
therefore, if you know of where I can learn all the CPU capabilities, pls link to it,
or if not, but you can explain any of 'em that can affect video-editing, please tell me.

* pae ( VirtualBox was set to DISable PAE, so I don't understand why this was visible in the CPU, but can't imagine it'd influence Premiere Element 7's speed, or Neo Screen, ftm )

* sep

* syscall

* nx ( I gather this's good for blocking some rootkits/viruses, but makes no speed diff )

* rdtscp

* lm

* rep_good

* lahf_lm

I didn't find anything useful in /usr/src/linux/Documentation
( no cpuinfo file in there, and the proc.txt wasn't any help )

Thanks in advance,

Old 03-10-2009, 07:47 AM   #2
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Distribution: linuxdebian
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Heres a couple sites you can look at for info on the cpu flags..

Hope that helps..

pae is still visible because it's a reported function of the CPU.. just because the function exists doesn't mean the system has to use it, or that the hardware won't still report the capability.

Just like lm is always reported even if you are not running 64 bit..

Last edited by farslayer; 03-10-2009 at 07:51 AM.
Old 03-11-2009, 12:04 AM   #3
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Registered: Oct 2007
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found RDTSCP...

it speeds up gettimeofday() calls significantly,
and makes certain that the call is answered atomically,
it seems.

Apparently important for databases,
which make many such calls
( drop from ~300 cycles for the call to ~200 cycles, more or less ).

still digging for the rest, and just discovered the previous reply,
which I'm gonna dig into in a moment...

Thanks, btw, eh?

Ach, me noodles are done...


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