Message-ID: <43421F46.8030202@comcast.net>
Date: Tue, 04 Oct 2005 02:20:54 -0400
From: John Richard Moser <nigelenki@comcast.net>
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To: Dan C Marinescu <dan_c_marinescu@yahoo.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: The price of SELinux (CPU)
References: <20051004050602.10057.qmail@web35501.mail.mud.yahoo.com>
In-Reply-To: <20051004050602.10057.qmail@web35501.mail.mud.yahoo.com>
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I'm not an expert in this kind of stuff.  I wonder where the numbers
come from; i.e. is 7% from policy?  A O(1) policy lookup would be immune
to big policies; a O(n) would probably not have that much impact from a
typical policy lookup.  Still perhaps interpreting the policy is a chore
in itself, which still says bigger policy means bigger hit.  Or is 7%
constant?

I don't know what the frame of reference is or was.  I'm sure with
selinux with no policy it's rather 0ish; what I don't know is what I'm
supposed to be looking at for benchmarking.  Just randomly turning
SELinux on and off and looking might give me an invalid measure.

Dan C Marinescu wrote:
> i suggested you to disable selinux in order to have
> something to compare to... (engineers compare,
> measure, instead of believing in rummors...)
> 
>    d
> 
> --- John Richard Moser <nigelenki@comcast.net> wrote:
> 
> 
> I'm not an abortionist; if I hear something has an
> ugly side, I try to
> find out if it can be fixed, and if the trade-off is
> worth getting rid
> of it.  SELinux and LSM are quite useful you know;
> the overhead is
> probably not even that significant on the desktop to
> gamers (although if
> you TELL them about it they'll piss themselves),
> from a practical
> viewpoint considering their excessive hardware.
> 
> Dan C Marinescu wrote:
> 
>>try selinux=0, _if u feel that way :-)
> 
>>about big o:
> 
> 
> 
>> http://www.maththinking.com/boat/compsciBooksIndex.html
> 
>>   daniel
> 
> 
> 
>>--- John Richard Moser <nigelenki@comcast.net>
> 
> wrote:
> 
> 
>>I've heard that SELinux has produced benchmarks
> 
> such
> 
>>as 7% increased CPU
>>load.  Is this true and current?  Is it dependent
> 
> on
> 
>>policy?  What is
>>the policy lookup complexity ( O(1), O(n),
>>O(nlogn)...)?  Are there
>>other places where a bottleneck may exist aside
> 
> from
> 
>>gruffing with the
>>policy?  Isn't the policy actually in xattrs so
> 
> it's
> 
>>O(1)?  Where else
>>would an overhead that big come from aside from a
>>lookup in a table?
> 
>>....
> 
>>Why is the sky blue?  Why do you have a mustach? 
>>Why doesn't mommy have
>>one?  Does she shave it?
> 
>>At any rate, my personal end goal is a secure
>>high-performance operating
>>system, as user friendly as Ubuntu, Mandriva, or
>>Win----.  To this end,
>>I'm (still; a lot of you have seen me before)
>>evaluating the performance
>>hit of various user and kernel security
> 
> enhancements
> 
>>like PaX,
>>ProPolice, various OpenWall/GrSecurity niceness
> 
> that
> 
>>needs to be divided
>>out, and of course LSM/SELinux.  Also wondering
>>about that PHKMalloc
>>thing on openbsd; is it really all that, is it
> 
> junk,
> 
>>how's it compare to
>>the recent ptmalloc work, and can it run on Linux
>>for direct benching .
>>. . but that's off topic.
> 
>>--
>>All content of all messages exchanged herein are
>>left in the
>>Public Domain, unless otherwise explicitly stated.
> 
>>    Creative brains are a valuable, limited
>>resource. They shouldn't be
>>    wasted on re-inventing the wheel when there
> 
> are
> 
>>so many fascinating
>>    new problems waiting out there.
> 
> 
> --
> 
>>Eric Steven Raymond
> 
> -
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> 
>>__________________________________ 
>>Yahoo! Mail - PC Magazine Editors' Choice 2005 
>>http://mail.yahoo.com
> 
> 
> --
> All content of all messages exchanged herein are
> left in the
> Public Domain, unless otherwise explicitly stated.
> 
>     Creative brains are a valuable, limited
> resource. They shouldn't be
>     wasted on re-inventing the wheel when there are
> so many fascinating
>     new problems waiting out there.
>                                                  --
> Eric Steven Raymond
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> __________________________________ 
> Yahoo! Mail - PC Magazine Editors' Choice 2005 
> http://mail.yahoo.com


- --
All content of all messages exchanged herein are left in the
Public Domain, unless otherwise explicitly stated.

    Creative brains are a valuable, limited resource. They shouldn't be
    wasted on re-inventing the wheel when there are so many fascinating
    new problems waiting out there.
                                                 -- Eric Steven Raymond
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