Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 27 Mar 2023 18:50:13 +0200 | Subject | Re: [PATCH v3 15/24] thermal: intel: hfi: Report the IPC class score of a CPU |
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On Tue, Feb 7, 2023 at 6:02 AM Ricardo Neri <ricardo.neri-calderon@linux.intel.com> wrote: > > Implement the arch_get_ipcc_score() interface of the scheduler. Use the > performance capabilities of the extended Hardware Feedback Interface table > as the IPC score. > > Cc: Ben Segall <bsegall@google.com> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: Ionela Voinescu <ionela.voinescu@arm.com> > Cc: Joel Fernandes (Google) <joel@joelfernandes.org> > Cc: Len Brown <len.brown@intel.com> > Cc: Lukasz Luba <lukasz.luba@arm.com> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Tim C. Chen <tim.c.chen@intel.com> > Cc: Valentin Schneider <vschneid@redhat.com> > Cc: x86@kernel.org > Cc: linux-pm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> > --- > Changes since v2: > * None > > Changes since v1: > * Adjusted the returned HFI class (which starts at 0) to match the > scheduler IPCC class (which starts at 1). (PeterZ) > * Used the new interface names. > --- > arch/x86/include/asm/topology.h | 2 ++ > drivers/thermal/intel/intel_hfi.c | 27 +++++++++++++++++++++++++++ > 2 files changed, 29 insertions(+) > > diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h > index ffcdac3f398f..c4fcd9c3c634 100644 > --- a/arch/x86/include/asm/topology.h > +++ b/arch/x86/include/asm/topology.h > @@ -229,8 +229,10 @@ void init_freq_invariance_cppc(void); > > #if defined(CONFIG_IPC_CLASSES) && defined(CONFIG_INTEL_HFI_THERMAL) > void intel_hfi_update_ipcc(struct task_struct *curr); > +unsigned long intel_hfi_get_ipcc_score(unsigned short ipcc, int cpu); > > #define arch_update_ipcc intel_hfi_update_ipcc > +#define arch_get_ipcc_score intel_hfi_get_ipcc_score > #endif /* defined(CONFIG_IPC_CLASSES) && defined(CONFIG_INTEL_HFI_THERMAL) */ > > #endif /* _ASM_X86_TOPOLOGY_H */ > diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c > index 530dcf57e06e..fa9b4a678d92 100644 > --- a/drivers/thermal/intel/intel_hfi.c > +++ b/drivers/thermal/intel/intel_hfi.c > @@ -206,6 +206,33 @@ void intel_hfi_update_ipcc(struct task_struct *curr) > curr->ipcc = msr.split.classid + 1; > } > > +unsigned long intel_hfi_get_ipcc_score(unsigned short ipcc, int cpu) > +{ > + unsigned short hfi_class;
It looks like the variable above is only used to save a subtraction or addition of 1 to something going forward.
> + int *scores; > + > + if (cpu < 0 || cpu >= nr_cpu_ids) > + return -EINVAL; > + > + if (ipcc == IPC_CLASS_UNCLASSIFIED) > + return -EINVAL; > + > + /* > + * Scheduler IPC classes start at 1. HFI classes start at 0. > + * See note intel_hfi_update_ipcc(). > + */ > + hfi_class = ipcc - 1; > + > + if (hfi_class >= hfi_features.nr_classes)
Personally, I would do
if (ipcc >= hfi_features.nr_classes + 1)
here and ->
> + return -EINVAL; > + > + scores = per_cpu_ptr(hfi_ipcc_scores, cpu); > + if (!scores) > + return -ENODEV; > +
-> scores[ipcc - 1]
below.
> + return READ_ONCE(scores[hfi_class]);
And why does this need to use READ_ONCE()?
> +} > + > static int alloc_hfi_ipcc_scores(void) > { > if (!cpu_feature_enabled(X86_FEATURE_ITD)) > --
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