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Message-ID: <CAJZ5v0iidC0LxqpE60J5HHQhvv8iHjMGdxM89-7p-QQE99qVEQ@mail.gmail.com>
Date: Mon, 27 Mar 2023 18:50:13 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Ricardo Neri <ricardo.neri@...el.com>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Ben Segall <bsegall@...gle.com>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Len Brown <len.brown@...el.com>, Mel Gorman <mgorman@...e.de>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Steven Rostedt <rostedt@...dmis.org>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Valentin Schneider <vschneid@...hat.com>,
Lukasz Luba <lukasz.luba@....com>,
Ionela Voinescu <ionela.voinescu@....com>, x86@...nel.org,
"Joel Fernandes (Google)" <joel@...lfernandes.org>,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
"Tim C . Chen" <tim.c.chen@...el.com>
Subject: Re: [PATCH v3 15/24] thermal: intel: hfi: Report the IPC class score
of a CPU
On Tue, Feb 7, 2023 at 6:02 AM Ricardo Neri
<ricardo.neri-calderon@...ux.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@...gle.com>
> Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
> Cc: Dietmar Eggemann <dietmar.eggemann@....com>
> Cc: Ionela Voinescu <ionela.voinescu@....com>
> Cc: Joel Fernandes (Google) <joel@...lfernandes.org>
> Cc: Len Brown <len.brown@...el.com>
> Cc: Lukasz Luba <lukasz.luba@....com>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Tim C. Chen <tim.c.chen@...el.com>
> Cc: Valentin Schneider <vschneid@...hat.com>
> Cc: x86@...nel.org
> Cc: linux-pm@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.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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