cvs commit: src/sys/libkern mcount.c

[Kip Macy]

On 6/12/07, Bruce Evans <bde at freebsd.org> wrote:
> bde         2007-06-13 06:17:48 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/libkern          mcount.c
>   Log:
>   Unbreak high resolution profiling a little: use dummy asms to prevent
>   timing loops being optimized away.
>
>   Once apon a time, gcc promised not to optimize away timing loops, but
>   gcc started optimizing away the call to a null function in the timing
>   loop here some time between gcc-3.3.3 and gcc-3.4.6, and it started
>   optimizing away the timing loop itself some time between gcc-3.4.6
>   and gcc-4.2.


Will this fix the hang on boot that I saw earlier today?

-Kip