On Mon, Oct 21, 2019 at 01:03:02PM -0700, [email protected] wrote: > From: Kan Liang <[email protected]> > > In LBR call stack mode, the depth of reconstructed LBR call stack limits > to the number of LBR registers. With LBR Top-of-Stack (TOS) information, > perf tool may stitch the stacks of two samples. The reconstructed LBR > call stack can break the HW limitation. > > Add a new branch sample type to retrieve LBR TOS. > > Only when the new branch sample type is set, the TOS information is > dumped into the PERF_SAMPLE_BRANCH_STACK output. > Perf tool should check the attr.branch_sample_type, and apply the > corresponding format for PERF_SAMPLE_BRANCH_STACK samples. > Otherwise, some user case may be broken. For example, users may parse a > perf.data, which include the new branch sample type, with an old version > perf tool (without the check). Users probably get incorrect information > without any warning. > > Signed-off-by: Kan Liang <[email protected]> > --- > include/linux/perf_event.h | 4 ++++ > include/uapi/linux/perf_event.h | 10 +++++++++- > kernel/events/core.c | 10 ++++++++++ > 3 files changed, 23 insertions(+), 1 deletion(-) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 61448c19a132..0cebc8ec44fa 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -972,6 +972,10 @@ struct perf_sample_data { > u64 stack_user_size; > > u64 phys_addr; > + > + /* PMU specific data */ > + u64 lbr_tos; > + > } ____cacheline_aligned;
Last time you put this in perf_branch_stack, that was a much better place. Can't this work now?
