Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Mon, 27 Mar 2023 18:42:28 +0200 | Subject | Re: [PATCH v3 14/24] thermal: intel: hfi: Update the IPC class of the current task |
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On Tue, Feb 7, 2023 at 6:02 AM Ricardo Neri <ricardo.neri-calderon@linux.intel.com> wrote: > > Use Intel Thread Director classification to update the IPC class of a > task. Implement the arch_update_ipcc() interface of the scheduler. > > 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: > * Removed the implementation of arch_has_ipc_classes(). > > Changes since v1: > * Adjusted the result the classification of Intel Thread Director to start > at class 1. Class 0 for the scheduler means that the task is > unclassified. > * Redefined union hfi_thread_feedback_char_msr to ensure all > bit-fields are packed. (PeterZ) > * Removed CONFIG_INTEL_THREAD_DIRECTOR. (PeterZ) > * Shortened the names of the functions that implement IPC classes. > * Removed argument smt_siblings_idle from intel_hfi_update_ipcc(). > (PeterZ) > --- > arch/x86/include/asm/topology.h | 6 ++++++ > drivers/thermal/intel/intel_hfi.c | 32 +++++++++++++++++++++++++++++++ > 2 files changed, 38 insertions(+) > > diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h > index 458c891a8273..ffcdac3f398f 100644 > --- a/arch/x86/include/asm/topology.h > +++ b/arch/x86/include/asm/topology.h > @@ -227,4 +227,10 @@ void init_freq_invariance_cppc(void); > #define arch_init_invariance_cppc init_freq_invariance_cppc > #endif > > +#if defined(CONFIG_IPC_CLASSES) && defined(CONFIG_INTEL_HFI_THERMAL) > +void intel_hfi_update_ipcc(struct task_struct *curr); > + > +#define arch_update_ipcc intel_hfi_update_ipcc > +#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 b06021828892..530dcf57e06e 100644 > --- a/drivers/thermal/intel/intel_hfi.c > +++ b/drivers/thermal/intel/intel_hfi.c > @@ -72,6 +72,17 @@ union cpuid6_edx { > u32 full; > }; > > +#ifdef CONFIG_IPC_CLASSES > +union hfi_thread_feedback_char_msr { > + struct { > + u64 classid : 8; > + u64 __reserved : 55; > + u64 valid : 1; > + } split; > + u64 full; > +}; > +#endif > + > /** > * struct hfi_cpu_data - HFI capabilities per CPU > * @perf_cap: Performance capability > @@ -174,6 +185,27 @@ static struct workqueue_struct *hfi_updates_wq; > #ifdef CONFIG_IPC_CLASSES > static int __percpu *hfi_ipcc_scores; > > +void intel_hfi_update_ipcc(struct task_struct *curr) > +{ > + union hfi_thread_feedback_char_msr msr; > + > + /* We should not be here if ITD is not supported. */ > + if (!cpu_feature_enabled(X86_FEATURE_ITD)) { > + pr_warn_once("task classification requested but not supported!"); > + return; > + } > + > + rdmsrl(MSR_IA32_HW_FEEDBACK_CHAR, msr.full); > + if (!msr.split.valid) > + return; > + > + /* > + * 0 is a valid classification for Intel Thread Director. A scheduler > + * IPCC class of 0 means that the task is unclassified. Adjust. > + */ > + curr->ipcc = msr.split.classid + 1; > +}
Wouldn't it be better to return the adjusted value from this function and let the caller store it where appropriate?
It doesn't look like it is necessary to pass the task_struct pointer to it.
> + > static int alloc_hfi_ipcc_scores(void) > { > if (!cpu_feature_enabled(X86_FEATURE_ITD)) > --
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