Re: linux-next: add utrace tree

Andi Kleen
2010-01-26T17:33:30Z

Tom Tromey <tromey@redhat.com> writes:

> * Use an fd, not SIGCHLD+wait, to report inferior state changes to gdb.
> Internally we're already using a self-pipe to integrate this into
> gdb's main loop. Relatedly, don't mess with the inferior's parentage.

How would having a kernel based solution be better over your
user space simulation?

BTW there's the new signalfd() system call that might do it
(haven't checked if it works for SIGCHLD)

> * Support "displaced stepping" in the kernel; I think this would improve
> performance when debugging in non-stop mode.

Not sure what "displaced stepping" is exactly, but it
sounds like the branch tracing extensions that got added a
few releases ago? On modern Intel chips they give you a branch
buffer in memory.

-Andi
--
ak@linux.intel.com -- Speaking for myself only.