linux-kernel - Re: [PATCH v4 04/11] perf/x86/rapl: Make rapl

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Message-ID: <f73f64390c0479c962b591d94c89b3eb4aa55e84.camel@intel.com>
Date: Fri, 12 Jul 2024 03:03:02 +0000
From: "Zhang, Rui" <rui.zhang@...el.com>
To: "alexander.shishkin@...ux.intel.com" <alexander.shishkin@...ux.intel.com>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>, "Hunter, Adrian"
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	<kees@...nel.org>, "mark.rutland@....com" <mark.rutland@....com>,
	"peterz@...radead.org" <peterz@...radead.org>, "Dhananjay.Ugwekar@....com"
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CC: "ravi.bangoria@....com" <ravi.bangoria@....com>, "kprateek.nayak@....com"
	<kprateek.nayak@....com>, "gautham.shenoy@....com" <gautham.shenoy@....com>,
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	<linux-pm@...r.kernel.org>
Subject: Re: [PATCH v4 04/11] perf/x86/rapl: Make rapl_model struct global

On Thu, 2024-07-11 at 10:24 +0000, Dhananjay Ugwekar wrote:
> To support AMD's per_core RAPL counter, we will need to check
> per_core capability of the current rapl_model multiple times in
> rapl_cpu_online/offline, init_rapl_pmus functions, so cache the
> matched rapl model in a global variable, to avoid calling
> x86_match_cpu() multiple times.
> 
> No functional change.
> 
> Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>

Reviewed-by: Zhang Rui <rui.zhang@...el.com>

-rui
> ---
>  arch/x86/events/rapl.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> index c3afeaf679c2..4ee0877eb4d8 100644
> --- a/arch/x86/events/rapl.c
> +++ b/arch/x86/events/rapl.c
> @@ -146,6 +146,7 @@ static cpumask_t rapl_cpu_mask;
>  static unsigned int rapl_cntr_mask;
>  static u64 rapl_timer_ms;
>  static struct perf_msr *rapl_msrs;
> +static struct rapl_model *rapl_model;
>  
>  /*
>   * Helper functions to get the correct topology macros according to
> the
> @@ -621,18 +622,18 @@ static int rapl_cpu_online(unsigned int cpu)
>         return 0;
>  }
>  
> -static int rapl_check_hw_unit(struct rapl_model *rm)
> +static int rapl_check_hw_unit(void)
>  {
>         u64 msr_rapl_power_unit_bits;
>         int i;
>  
>         /* protect rdmsrl() to handle virtualization */
> -       if (rdmsrl_safe(rm->msr_power_unit,
> &msr_rapl_power_unit_bits))
> +       if (rdmsrl_safe(rapl_model->msr_power_unit,
> &msr_rapl_power_unit_bits))
>                 return -1;
>         for (i = 0; i < NR_RAPL_DOMAINS; i++)
>                 rapl_hw_unit[i] = (msr_rapl_power_unit_bits >> 8) &
> 0x1FULL;
>  
> -       switch (rm->unit_quirk) {
> +       switch (rapl_model->unit_quirk) {
>         /*
>          * DRAM domain on HSW server and KNL has fixed energy unit
> which can be
>          * different than the unit from power unit MSR. See
> @@ -846,21 +847,20 @@ MODULE_DEVICE_TABLE(x86cpu, rapl_model_match);
>  static int __init rapl_pmu_init(void)
>  {
>         const struct x86_cpu_id *id;
> -       struct rapl_model *rm;
>         int ret;
>  
>         id = x86_match_cpu(rapl_model_match);
>         if (!id)
>                 return -ENODEV;
>  
> -       rm = (struct rapl_model *) id->driver_data;
> +       rapl_model = (struct rapl_model *) id->driver_data;
>  
> -       rapl_msrs = rm->rapl_msrs;
> +       rapl_msrs = rapl_model->rapl_msrs;
>  
>         rapl_cntr_mask = perf_msr_probe(rapl_msrs, PERF_RAPL_MAX,
> -                                       false, (void *) &rm->events);
> +                                       false, (void *) &rapl_model-
> >events);
>  
> -       ret = rapl_check_hw_unit(rm);
> +       ret = rapl_check_hw_unit();
>         if (ret)
>                 return ret;
>