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Date:      Mon, 24 Nov 2003 19:43:27 -0500
From:      Garance A Drosihn <drosih@rpi.edu>
To:        freebsd-current@freebsd.org
Subject:   Re: 40% slowdown with dynamic /bin/sh
Message-ID:  <p06002008bbe852e1c695@[128.113.24.47]>
In-Reply-To: <16322.26365.159173.946033@grasshopper.cs.duke.edu>
References:  <16322.26365.159173.946033@grasshopper.cs.duke.edu>

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At 3:15 PM -0500 11/24/03, Andrew Gallatin wrote:
>Here is a simple test which times the execution of a null
>shell script.  It basically times fork/exec of the chosen
>shell.

>So.. forking a dynamic sh is roughly 40% more expensive
>than forking a static copy of sh.  This is embarrassing.

To be more precise: shell scripts which do-nothing will
be 40% more expensive than they used to be.  It is not
like the entire operating system will get 40% slower.

>I propose that we at least make /bin/sh static.

I suggest that we leave all of /bin and /sbin as it is for
5.2-release.  We are still telling users that 5.2 is a
snapshot of "-current", and it is more valuable to have a
wider range of experience with this worst-case scenario.
("worst-case" == all files dynamically linked).

We certainly may want to make changes to address the
performance issues that you note, but there is no reason
we must decide *which* change should be made right now.

-- 
Garance Alistair Drosehn            =   gad@gilead.netel.rpi.edu
Senior Systems Programmer           or  gad@freebsd.org
Rensselaer Polytechnic Institute    or  drosih@rpi.edu



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