Messages in this thread | | | Date | Tue, 26 Feb 2008 09:55:41 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: add the debugfs interface for the sysprof tool |
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* Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> Hi, > > On Tue, Feb 26, 2008 at 8:27 AM, Pekka Enberg <penberg@cs.helsinki.fi> wrote: > > > You could try passing the --callgraph option to opcontrol. > > > > Hmm, perhaps I am missing something but I don't think that does what > > sysprof does. At least I can't find where in the oprofile kernel code > > does it save the full stack trace for user-space. John? > > Ok, so as pointed out by Nicholas/Andrew, oprofile does indeed do > exactly what sysprof does (see > arch/x86/oprofile/backtrace.c::backtrace_address, for example). So, > Soeren, any other reason we can't use the oprofile kernel module for > sysprof?
as i pointed it out earlier in the thread, the oprofile implementation seems buggy because when an event comes from NMI context __copy_from_user_inatomic() can fault and re-enable NMIs - causing possible stack recursion/corruption. Does not look like an easy fix.
Ingo
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