Subject: Re: selftests/powerpc: Remove -flto from common CFLAGS

From: Michael Ellerman <[email-masked]>
Date: Tue, 01 Mar 2016 10:35:14 +1100

On Tue, 2016-03-01 at 10:08 +1100, Cyril Bur wrote:
> On Mon, 29 Feb 2016 22:10:13 +1100 (AEDT)
> Michael Ellerman <[email-masked]> wrote:
> > On Mon, 2016-29-02 at 06:29:55 UTC, Suraj Jitindar Singh wrote:
> > > Both these cases are hard to detect and require manual inspection of
> > > binaries which is unlikely to happen for all tests. Furthermore, LTO
> > > optimisations are not necessary for selftests and correctness is paramount
> > > and as such it is best to disable LTO.
> > >
> > > LTO can be enabled on a per test basis.
> > >
> > > A pseries_le_defconfig kernel on a POWER8 was used to determine that the
> > > same subset of selftests pass and fail with and without -flto in the
> > > common Makefile.
> > >
> > > These tests always fail:
> > > selftests: per_event_excludes [FAIL]
> > > selftests: event_attributes_test [FAIL]
> > > selftests: ebb_vs_cpu_event_test [FAIL]
> > > selftests: cpu_event_vs_ebb_test [FAIL]
> > > selftests: cpu_event_pinned_vs_ebb_test [FAIL]
> >
> > They shouldn't :)
> >
> > Are you running as root? Bare metal or guest?
>
> Interesting. I believe this was run baremetal as root. I'm going to test the
> patch in qemu at root. Is there a list of expected failures in certain
> situations?

Nope.

Most of those require the perf paranoid level to be set, see eg:

  tools/testing/selftests/powerpc/pmu/ebb/cpu_event_vs_ebb_test.c:        SKIP_IF(require_paranoia_below(1));

cheers