Re: [ANNOUNCE] New utility: 'trace'

[TÃrÃk Edwin]

On Wed, 17 Nov 2010 13:51:52 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, 2010-11-17 at 14:47 +0200, TÃrÃk Edwin wrote:
> > I see --call-graph in the trace record -h output, but it doesn't
> > seem to work on x86_64 for me.
> 
> If you want to unwind userspace you need to build everything with
> framepointers -- sadly some people have been lobbying to remove
> framepointers from all distro builds, even though on x86_64 its nearly
> free (i386 does have a significant performance benefit, sadly).
> 
> There's some work on-going to simply copy out the top of stack and let
> dwarves go wild at it in userspace, but that isn't done yet.

Even without frame-pointers I should see at least the first caller in
userspace, since that can be obtained by reading the return address of
the syscall, right?
I don't see any difference in the output of 'trace report' thats why
I'm asking it is implemented at all right now, or I need additional
flags to see it.

I do see some difference in output of 'perf record -g/perf report'
though.

Best regards,
--Edwin


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/