linux-kernel - Re: [tip:perf/core] perf/x86/intel/rapl: Sanitize the quirk handling

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Date:	Tue, 8 Mar 2016 17:04:19 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	linux-tip-commits@...r.kernel.org, torvalds@...ux-foundation.org,
	eranian@...gle.com, harish.chegondi@...el.com, acme@...hat.com,
	jolsa@...hat.com, peterz@...radead.org, hpa@...or.com,
	andi.kleen@...el.com, vincent.weaver@...ne.edu,
	kan.liang@...el.com, jacob.jun.pan@...ux.intel.com,
	linux-kernel@...r.kernel.org
Subject: Re: [tip:perf/core] perf/x86/intel/rapl: Sanitize the quirk handling


* Borislav Petkov <bp@...en8.de> wrote:

> On Mon, Feb 29, 2016 at 03:10:28AM -0800, tip-bot for Thomas Gleixner wrote:
> > Commit-ID:  b8b3319a471b2df35ae0a8fe94223638468e9ca4
> > Gitweb:     http://git.kernel.org/tip/b8b3319a471b2df35ae0a8fe94223638468e9ca4
> > Author:     Thomas Gleixner <tglx@...utronix.de>
> > AuthorDate: Mon, 22 Feb 2016 22:19:22 +0000
> > Committer:  Ingo Molnar <mingo@...nel.org>
> > CommitDate: Mon, 29 Feb 2016 09:35:22 +0100
> > 
> > perf/x86/intel/rapl: Sanitize the quirk handling
> > 
> > There is no point in having a quirk machinery for a single possible
> > function. Get rid of it and move the quirk to a place where it actually
> > makes sense.
> 
> I guess you can simplify this even more by even getting rid of that
> quirk function pointer funkyness and simply tell rapl_check_hw_unit() to
> apply the quirk.
> 
> Diff ontop of yours:
> 
> ---
> diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
> index 019e541fa988..0b72976bab35 100644
> --- a/arch/x86/events/intel/rapl.c
> +++ b/arch/x86/events/intel/rapl.c
> @@ -592,18 +592,7 @@ static int rapl_cpu_notifier(struct notifier_block *self,
>  	return NOTIFY_OK;
>  }
>  
> -static __init void rapl_hsw_server_quirk(void)
> -{
> -	/*
> -	 * DRAM domain on HSW server has fixed energy unit which can be
> -	 * different than the unit from power unit MSR.
> -	 * "Intel Xeon Processor E5-1600 and E5-2600 v3 Product Families, V2
> -	 * of 2. Datasheet, September 2014, Reference Number: 330784-001 "
> -	 */
> -	rapl_hw_unit[RAPL_IDX_RAM_NRG_STAT] = 16;
> -}
> -
> -static int rapl_check_hw_unit(void (*quirk)(void))
> +static int rapl_check_hw_unit(bool apply_quirk)
>  {
>  	u64 msr_rapl_power_unit_bits;
>  	int i;
> @@ -614,9 +603,14 @@ static int rapl_check_hw_unit(void (*quirk)(void))
>  	for (i = 0; i < NR_RAPL_DOMAINS; i++)
>  		rapl_hw_unit[i] = (msr_rapl_power_unit_bits >> 8) & 0x1FULL;
>  
> -	/* Apply cpu model quirk */
> -	if (quirk)
> -		quirk();
> +	/*
> +	 * DRAM domain on HSW server has fixed energy unit which can be
> +	 * different than the unit from power unit MSR.
> +	 * "Intel Xeon Processor E5-1600 and E5-2600 v3 Product Families, V2
> +	 * of 2. Datasheet, September 2014, Reference Number: 330784-001 "
> +	 */
> +	if (apply_quirk)
> +		rapl_hw_unit[RAPL_IDX_RAM_NRG_STAT] = 16;
>  
>  	/*
>  	 * Calculate the timer rate:
> @@ -704,7 +698,7 @@ static const struct x86_cpu_id rapl_cpu_match[] __initconst = {
>  
>  static int __init rapl_pmu_init(void)
>  {
> -	void (*quirk)(void) = NULL;
> +	bool apply_quirk = false;
>  	int ret;
>  
>  	if (!x86_match_cpu(rapl_cpu_match))
> @@ -717,7 +711,7 @@ static int __init rapl_pmu_init(void)
>  		rapl_pmu_events_group.attrs = rapl_events_cln_attr;
>  		break;
>  	case 63: /* Haswell-Server */
> -		quirk = rapl_hsw_server_quirk;
> +		apply_quirk = true;
>  		rapl_cntr_mask = RAPL_IDX_SRV;
>  		rapl_pmu_events_group.attrs = rapl_events_srv_attr;
>  		break;
> @@ -733,7 +727,7 @@ static int __init rapl_pmu_init(void)
>  		rapl_pmu_events_group.attrs = rapl_events_srv_attr;
>  		break;
>  	case 87: /* Knights Landing */
> -		quirk = rapl_hsw_server_quirk;
> +		apply_quirk = true;
>  		rapl_cntr_mask = RAPL_IDX_KNL;
>  		rapl_pmu_events_group.attrs = rapl_events_knl_attr;
>  		break;
> @@ -741,7 +735,7 @@ static int __init rapl_pmu_init(void)
>  		return -ENODEV;
>  	}
>  
> -	ret = rapl_check_hw_unit(quirk);
> +	ret = rapl_check_hw_unit(apply_quirk);
>  	if (ret)
>  		return ret;

Please send a patch with a changelog so it can be applied.

Thanks!

	Ingo