On Fri, Sep 28, 2012 at 10:43 AM, Peter Zijlstra <[email protected]> wrote: > On Thu, 2012-09-27 at 21:31 -0700, Andi Kleen wrote: >> + if (event->attr.precise_ip > 1 && >> x86_pmu.intel_cap.pebs_format < 2) { > > Shouldn't that be: && x86_pmu.intel_cap.pebs_trap, like most other sites > instead? Or didn't they flip the trap capability on Haswell?
On Haswell, you get the event_ip which points to the sampled instruction, i.e., the off-by-one error can be avoided by using that value instead of pebs.rip. The nice side effect is that you free the LBR and minimize the overhead (no fixups). Therfore the LBR filter can have any setting when combined with PEBS, thus we do not need to check for compatibility nor force any setting for the LBR filter. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
