restoring the list.. I really should drop all emails you send off list into /dev/null.
On Wed, Jan 08, 2014 at 09:28:40AM +0100, Peter Zijlstra wrote: > On Tue, Jan 07, 2014 at 10:23:22PM +0100, Andi Kleen wrote: > > > Yes we very much rely on the FREEZE bits for LBR. PT and LBR being > > > mutually exclusive wasn't documented (or I missed it) and completely > > > blows. > > > > Can you describe why it is a problem? I had considered it only a minor > > inconvenience, for many things you would use LBRs for PT is far better. > > Because is someone writes a GCC tool using perf-LBR support for some > basic block analysis, and someone else writes another tool for PT, then > the first tool magically stops working when the PT tool is started. > > We cannot refuse to create perf-LBR events, because at that time there > might not be a PT user -- and even if there was one, it might go away. > > But as long as there's a PT user around, the LBR events will not be able > to be scheduled and will simply starve, for no apparent reason. > > Complete and utterly miserable position. > > And it makes sense to write LBR tools because they cover a much greater > spread of hardware. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
