Messages in this thread | | | Date | Wed, 10 Jun 2009 14:51:08 +0200 | From | Ingo Molnar <> | Subject | Re: [tip:tracing/core] x86, bts: reenable ptrace branch trace support |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, 2009-05-07 at 09:25 +0000, tip-bot for Markus Metzger wrote: > > Commit-ID: 7e0bfad24d85de7cf2202a7b0ce51de11a077b21 > > Gitweb: http://git.kernel.org/tip/7e0bfad24d85de7cf2202a7b0ce51de11a077b21 > > Author: Markus Metzger <markus.t.metzger@intel.com> > > AuthorDate: Fri, 24 Apr 2009 09:44:48 +0200 > > Committer: Ingo Molnar <mingo@elte.hu> > > CommitDate: Fri, 24 Apr 2009 10:18:51 +0200 > > > > x86, bts: reenable ptrace branch trace support > > > > The races found by Oleg Nesterov have been fixed. > > > > Reenable branch trace support. > > > > Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> > > Acked-by: Oleg Nesterov <oleg@redhat.com> > > LKML-Reference: <20090424094448.A30216@sedona.ch.intel.com> > > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > OK, this whole BTS thing worries me because it seems to expose too > much of the Intel Debug Store thingy to the outside world. > > The thing is, once we do PEBS from inside the kernel, we'll have > to share the debug store, and the way this thing sets it up isn't > really going to work. > > So what I'd like to see is having this debug store removed from > the interface and abstracted away as cpu resource -- a single page > when in use should suffice I think. > > If you want to expose a buffer to userspace, use the regular > mmap() interface and fill those pages from the DS interrupt > handler.
hm, that makes sense indeed. We are in the merge window now - Markus, what's your suggestion?
Ingo
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