Re: linux-next: add utrace tree

From: Andi Kleen
Date: Tue Jan 26 2010 - 12:33:34 EST


Tom Tromey <tromey@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx -- Speaking for myself only.
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