Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Wed, 29 Mar 2023 14:13:29 +0200 | Subject | Re: [PATCH v3 14/24] thermal: intel: hfi: Update the IPC class of the current task |
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On Wed, Mar 29, 2023 at 1:31 AM Ricardo Neri <ricardo.neri-calderon@linux.intel.com> wrote: > > On Mon, Mar 27, 2023 at 06:42:28PM +0200, Rafael J. Wysocki wrote: > > 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. > > Judging from this patch alone, yes, it does not make much sense to pass a > task_struct as argument. In patch 21, however, this function uses various > members of task_struct and makes it more convenient to have it as argument, > no?
I'm not convinced about this, but anyway it is better to combine the two patches in such cases IMO.
The way it is done now confuses things from my perspective.
> > > > > + > > > static int alloc_hfi_ipcc_scores(void) > > > { > > > if (!cpu_feature_enabled(X86_FEATURE_ITD)) > > > --
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