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SubjectRe: A question sort_main_extable()
On Fri, 21 Nov 2008 13:42:56 +0800
"Peter Teoh" <htmldeveloper@gmail.com> wrote:

> Inside start_kernel() there is a call to sort_main_extable().
>
> void sort_extable(struct exception_table_entry *start,
> struct exception_table_entry *finish)
> {
> sort(start, finish - start, sizeof(struct
> exception_table_entry), cmp_ex, NULL);
> }
>
> With reference to
> http://tuxology.net/2008/07/08/benchmarking-boot-latency-on-x86/, I
> think it can help bootup latency (how much I got no number) if the
> sorting is done post-compilation time, instead of dynamically
> everytime the system bootup. (perhaps at the stage of modposting,
> when all the vmlinux, kernel modules objects have been generated, so
> extracting out the exceptions strings is possible?) Is this a
> possible optimization?

we used to do this but it was a pain and extremely fragile. Runtime
sorting makes it very robust at least.

The sort is really quick though; I've spent a lot of time on boot time
and this guy never showed up for me.



--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org


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