Subject: Re: Enhancing sysctl support in ld.elf_so
To: None <>
From: Christos Zoulas <>
List: tech-userlevel
Date: 06/21/2004 20:19:16
In article <>,
Thor Lancelot Simon <> wrote:
>On Mon, Jun 21, 2004 at 07:27:16PM +0000, Charles M. Hannum wrote:
>> Adding extra memory requirements and startup overhead for EVERY SINGLE EXEC() 
>> is not a reasonable tradeoff.  This is definitely a non-starter.
>How much memory (and overhead) are we talking about here?  Can we get a
>measurement of this?
>Clearly, if it were one byte, and one nanosecond, this change would be a
>win; if it's 100 kilobytes, and 100ms, it would be a lose.  But the added
>functionality does seem useful (after all, it lets us change libs on the
>basis of any sysctl node, and most ports expose a lot more MD nodes,
>including nodes that could be used to select optimized libraries, than
>the loader actually knows about now) and eliminating users of the old
>sysctl interface seems like a win, too, since it's deprecated and a
>maintenance hassle.

We are talking about 12K more of source and a few more sysctl() syscalls
(2 more minimum). The current code only knows about machdep.* mappings.