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Re: Linux kernel headers
On Thu, Jul 2, 2009 at 8:06 AM, Petr Baudis<pasky@suse.cz> wrote:
> Actually, it's the other way around I think.
>
> --enable-kernel is the _minimal_ version glibc supports. It means that
> it assumes that features present in this kernel version are present and
> it does not waste cycles checking their presence and having
> compatibility code compiled in. So, if you specify 2.6.30, your glibc
> may not work with 2.6.29, but if you specify 2.6.29, your glibc will
> certainly work with 2.6.30 (albeit slightly less efficiently in theory).
Yes you're right.. I can't believe I got this wrong considering how
long I worked with the ill-fated *context routines for PowerPC.
> I actually plan to do some benchmarks on how various settings affect
> this since for historical reasons, in SUSE we still use
> --enable-kernel=2.6.4. If you know about any existing benchmarks,
> I would appreciate that. :-)
There are two big features that I can think of that may demonstrate
marked improvement.
Private Futex support and Per Thread Malloc Arena (i.e. experimental malloc).
Lack of accessible benchmarks certainly seems to be an issue.
Ryan