linux-kernel - Re: [PATCH 3/8] ACPI: CPPC: Adjust debug messages in amd_set_max_freq

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Message-ID: <Zs3np8AeARzbMVSB@BLRRASHENOY1.amd.com>
Date: Tue, 27 Aug 2024 20:20:15 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Mario Limonciello <superm1@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>, Perry Yuan <perry.yuan@....com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <linux-kernel@...r.kernel.org>,
	"open list:ACPI" <linux-acpi@...r.kernel.org>,
	"open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
	Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH 3/8] ACPI: CPPC: Adjust debug messages in
 amd_set_max_freq_ratio() to warn

On Mon, Aug 26, 2024 at 04:13:53PM -0500, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> If the boost ratio isn't calculated properly for the system for any
> reason this can cause other problems that are non-obvious.
> 
> Raise all messages to warn instead.
> 
> Suggested-by: Perry Yuan <Perry.Yuan@....com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  arch/x86/kernel/acpi/cppc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
> index 1d631ac5ec328..e94507110ca24 100644
> --- a/arch/x86/kernel/acpi/cppc.c
> +++ b/arch/x86/kernel/acpi/cppc.c
> @@ -75,17 +75,17 @@ static void amd_set_max_freq_ratio(void)
>  
>  	rc = cppc_get_perf_caps(0, &perf_caps);
>  	if (rc) {
> -		pr_debug("Could not retrieve perf counters (%d)\n", rc);
> +		pr_warn("Could not retrieve perf counters (%d)\n", rc);
>  		return;
>  	}
>  
>  	rc = amd_get_boost_ratio_numerator(0, &highest_perf);
>  	if (rc)
> -		pr_debug("Could not retrieve highest performance\n");
> +		pr_warn("Could not retrieve highest performance\n");
>  	nominal_perf = perf_caps.nominal_perf;
>  
>  	if (!nominal_perf) {
> -		pr_debug("Could not retrieve nominal performance\n");
> +		pr_warn("Could not retrieve nominal performance\n");
>  		return;
>  	}
>  
> @@ -93,7 +93,7 @@ static void amd_set_max_freq_ratio(void)
>  	/* midpoint between max_boost and max_P */
>  	perf_ratio = (perf_ratio + SCHED_CAPACITY_SCALE) >> 1;
>  	if (!perf_ratio) {
> -		pr_debug("Non-zero highest/nominal perf values led to a 0 ratio\n");
> +		pr_warn("Non-zero highest/nominal perf values led to a 0 ratio\n");
>  		return;

Aside:
perf_ratio is a u64, and SCHED_CAPACITY_SCALE is (1L << 10). Thus, is
it even possible to have !perf_ratio?

Otherwise, I am ok with this promotion of pr_debug to pr_warn.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>

--
Thanks and Regards
gautham.