Subject: Re: Enhancing sysctl support in ld.elf_so
To: None <>
From: Christos Zoulas <>
List: tech-userlevel
Date: 06/21/2004 05:02:46
In article <>,
Andrew Brown <> wrote:
>On Sun, Jun 20, 2004 at 03:37:40PM -0700, Matt Thomas wrote:
>>At 12:10 PM 6/20/2004, Quentin Garnier wrote:
>>>Le Sun, 20 Jun 2004 19:47:02 +0200 (CEST)
>>>Jaromir Dolecek a ecrit :
>>> > Quentin Garnier wrote:
>>> > -- Start of PGP signed section.
>>> > > Hi,
>>> > >
>>> > > I made a patch to make ld.elf_so use the new sysctl API instead of the
>>> > > limited functionality it has now.
>>> > >
>>> > > It's handy, but adds 12k to ld.elf_so.
>>> > >
>>> > > Comments?
>>> >
>>> > What new features are provided by the new code, besides
>>> > using the new sysctl API (which is irrelevant) ?
>>>It allows the use of any sysctl variable in /etc/  I can't say
>>>it is a must have, but it's clearly handy in some case, such as with
>>>third-party libraries and such that would depend on specific features of
>>>the kernel.
>>>That's why I ask if those 12k are worth the feature, but nobody commented
>>>on that yet.
>>It isn't the 12K that bothers me, it's whether it slows down ld.elf_so
>>at all.  So, does it slow it down?  I assume the sysctlmib is only
>>initialized if needed, right??
>calling sysctlgetmibinfo() costs at least one call to sysctl() each
>time you call it (unless a private mib tree is used) and possibly up
>to "n" where "n" is the number of levels deep into the tree you are
>looking.  caching helps mitigate this for frequent callers, but
>ld.elf_so probably won't be a "frequent caller".

So we should leave things as they are.