Re: unwind_init() takes 100 ms

From: Ingo Molnar
Date: Tue Oct 09 2018 - 02:13:31 EST



* Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

> On Mon, Oct 08, 2018 at 12:34:17PM -0500, Josh Poimboeuf wrote:
> > > 4. Would a command line parameter be reasonable `disable_unwind`, so people
> > > could decrease their boot time with distribution kernels, and easily turn it
> > > back on, when they need a stacktrace without having to rebuild the Linux
> > > kernel?
> >
> > I think a boot cmdline option to disable ORC would be ok. However,
> > disabling ORC would need to fall back to the "guess" unwinder.
> > Otherwise it would make debugging impossible. That shouldn't be too
> > hard, but it would require restructuring the code a bit.
>
> But I should also clarify that this option wouldn't be worth it.
> Sorting at build time is the way to go.

Yep, very much so.

Thanks,

Ingo