* Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote:
> On Mon, Apr 1, 2024 at 2:30 AM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> >
> > * Andrii Nakryiko <andrii@xxxxxxxxxx> wrote:
> >
> > > Add AMD-specific implementation of perf_snapshot_branch_stack static call that
> > > allows LBR capture from arbitrary points in the kernel. This is utilized by
> > > BPF programs. See patch #3 for all the details.
> > >
> > > Patches #1 and #2 are preparatory steps to ensure LBR freezing is completely
> > > inlined and have no branches, to minimize LBR snapshot contamination.
> > >
> > > Patch #4 removes an artificial restriction on perf events with LBR enabled.
> > >
> > > Andrii Nakryiko (4):
> > > perf/x86/amd: ensure amd_pmu_core_disable_all() is always inlined
> > > perf/x86/amd: avoid taking branches before disabling LBR
> > > perf/x86/amd: support capturing LBR from software events
> > > perf/x86/amd: don't reject non-sampling events with configured LBR
> > >
> > > arch/x86/events/amd/core.c | 37 +++++++++++++++++++++++++++++++++++-
> > > arch/x86/events/amd/lbr.c | 11 +----------
> > > arch/x86/events/perf_event.h | 11 +++++++++++
> > > 3 files changed, 48 insertions(+), 11 deletions(-)
> >
> > So there's a new conflict with patch #2, probably due to interaction
> > with this recent fix that is now upstream:
> >
> > 598c2fafc06f ("perf/x86/amd/lbr: Use freeze based on availability")
> >
> > I don't think it should change the logic of the snapshot feature
> > materially, X86_FEATURE_AMD_LBR_PMC_FREEZE should be orthogonal to it,
> > as the LBR snapshot isn't taken from a PMI.
> >
>
> Yep, seems like there was a parallel change to related code in
> perf/urgent branch. And yes, you are right that it's orthogonal and
> doesn't regress anything as far as branching and whatnot (just
> retested everything on real hardware). So I've rebased my patches on
> top of perf/urgent, will send v5 momentarily.
Thank you - it's now all in tip:perf/core and lined up for v6.10.
> Sorry for an extra round on this.
Not your doing really - just crossing patches.
Thanks,
Ingo
