On 04-07-2013 23:54, Michael Ellerman wrote: > On Thu, Jul 04, 2013 at 03:58:01PM -0300, Adhemerval Zanella wrote: >> Hi Michael, >> >> I believe you forgot to add the cpu_user_features2 bit to announce the EBB >> support >> for P8, patch following: > Hi Adhemerval, > > You're right, I haven't added it. I was wondering how best to do it. > > It's possible to configure the kernel so that it doesn't have PMU > support, and in that case EBB is unsupported. It's also possible that > something > goes wrong with the PMU registration (kernel bug or OOM), and again EBB is > then > unsupported. > > So I think it might be better if we add PPC_FEATURE2_EBB at runtime in > init_power8_pmu(). > > What do you think? Indeed your approach seems better (I wasn't aware you could configure kernel with perf subsystem).
> > Something like: > > diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c > index c7f8ccc..fd9ed89 100644 > --- a/arch/powerpc/perf/power8-pmu.c > +++ b/arch/powerpc/perf/power8-pmu.c > @@ -620,10 +682,19 @@ static struct power_pmu power8_pmu = { > > static int __init init_power8_pmu(void) > { > + int rc; > + > if (!cur_cpu_spec->oprofile_cpu_type || > strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power8")) > return -ENODEV; > > - return register_power_pmu(&power8_pmu); > + rc = register_power_pmu(&power8_pmu); > + if (rc) > + return rc; > + > + /* Tell userspace that EBB is supported */ > + cur_cpu_spec->cpu_user_features2 |= PPC_FEATURE2_EBB; > + > + return 0; > } > early_initcall(init_power8_pmu); > > > cheers > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev