Re: [OT] Argument with an OS professor over profile=3

["Russ Dill" <russ.dill@gmail.com>]

On 10/10/07, David Newall <david@davidnewall.com> wrote:
> Russ Dill wrote:
> > I've been having a back and forth going for a while with my TA and OS
> > professor on the meaning of profile=3 and have been unable to convince
> > either of them. The basic question is if profile=3 is passed to kernel
> > with an 8MB text section, how big is the allocated profile buffer. His
> > answer is 1MB....
> >
> >         if (prof_shift) {
> >                 unsigned int size;
> >                 /* only text is profiled */
> >                 prof_len = (unsigned *) &_etext - (unsigned *) &_stext;
> >
> You stipulated 8MB text, but this calculates in unsigned ints, so
> prof_len = 2M.

Please have a look at my followup, I accidentally sent out code that I
had used to produce an answer as my prof thought it works. The actual
code casts to (unsigned long). Sigh, I've shot myself in the foot...

Anyway, the book (and the class covers 2.4.1) and the associated code
has since moved from init/main.c. Here's how the 2.4.1ish code looks:

http://tldp.org/HOWTO/Linux-i386-Boot-Code-HOWTO/init_main.html