From: Mario Limonciello <mario.limonciello@amd.com>
To: Perry Yuan <perry.yuan@amd.com>,
rafael.j.wysocki@intel.com, viresh.kumar@linaro.org,
Ray.Huang@amd.com, gautham.shenoy@amd.com,
Borislav.Petkov@amd.com
Cc: Alexander.Deucher@amd.com, Xinmei.Huang@amd.com,
Xiaojian.Du@amd.com, Li.Meng@amd.com, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/6] cpufreq:amd-pstate: get pstate transition delay and latency value from ACPI tables
Date: Wed, 31 Jan 2024 15:49:14 -0600 [thread overview]
Message-ID: <a0580854-b5d5-4bac-a35e-cc2613ccab2f@amd.com> (raw)
In-Reply-To: <872b172c350021ab3c55f80460c33473486e4241.1706690577.git.perry.yuan@amd.com>
On 1/31/2024 02:50, Perry Yuan wrote:
> make pstate driver initially retrieve the P-state transition delay and latency
> values from the BIOS ACPI tables which has more reasonable delay and latency
> values according to the platform design and requirements.
>
> Previously there values were hardcoded at specific value which may
> have conflicted with platform and it might not reflect the most accurate or
> optimized setting for the processor.
>
> [054h 0084 8] Preserve Mask : FFFFFFFF00000000
> [05Ch 0092 8] Write Mask : 0000000000000001
> [064h 0100 4] Command Latency : 00000FA0
> [068h 0104 4] Maximum Access Rate : 0000EA60
> [06Ch 0108 2] Minimum Turnaround Time : 0000
>
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
One comment below.
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> drivers/cpufreq/amd-pstate.c | 34 ++++++++++++++++++++++++++++++++--
> 1 file changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index db7b36afdce2..eea2e192d748 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -683,6 +683,36 @@ static void amd_perf_ctl_reset(unsigned int cpu)
> wrmsrl_on_cpu(cpu, MSR_AMD_PERF_CTL, 0);
> }
>
> +/**
> + * Get pstate transition delay time from ACPI tables that firmware set
> + * instead of using hardcode value directly.
> + */
> +static u32 amd_pstate_get_transition_delay_us(unsigned int cpu)
> +{
> + u32 transition_delay_ns;
> +
> + transition_delay_ns= cppc_get_transition_latency(cpu);
space before the =
> + if (transition_delay_ns == CPUFREQ_ETERNAL)
> + return AMD_PSTATE_TRANSITION_DELAY;
> +
> + return transition_delay_ns / NSEC_PER_USEC;
> +}
> +
> +/**
> + * Get pstate transition latency value from ACPI tables that firmware set
> + * instead of using hardcode value directly.
> + */
> +static u32 amd_pstate_get_transition_latency(unsigned int cpu)
> +{
> + u32 transition_latency;
> +
> + transition_latency = cppc_get_transition_latency(cpu);
> + if (transition_latency == CPUFREQ_ETERNAL)
> + return AMD_PSTATE_TRANSITION_LATENCY;
> +
> + return transition_latency;
> +}
> +
> static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> {
> int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> @@ -725,8 +755,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> goto free_cpudata1;
> }
>
> - policy->cpuinfo.transition_latency = AMD_PSTATE_TRANSITION_LATENCY;
> - policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
> + policy->cpuinfo.transition_latency = amd_pstate_get_transition_latency(policy->cpu);
> + policy->transition_delay_us = amd_pstate_get_transition_delay_us(policy->cpu);
>
> policy->min = min_freq;
> policy->max = max_freq;
next prev parent reply other threads:[~2024-01-31 21:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-31 8:50 [PATCH 0/6] AMD Pstate Fixes And Enhancements Perry Yuan
2024-01-31 8:50 ` [PATCH 1/6] ACPI: CPPC: enable AMD CPPC V2 support for family 17h processors Perry Yuan
2024-01-31 21:45 ` Mario Limonciello
2024-01-31 8:50 ` [PATCH 2/6] cpufreq:amd-pstate: fix the nominal freq value set Perry Yuan
2024-01-31 21:46 ` Mario Limonciello
2024-01-31 8:50 ` [PATCH 3/6] cpufreq:amd-pstate: initialize nominal_freq of each cpudata Perry Yuan
2024-01-31 21:47 ` Mario Limonciello
2024-01-31 8:50 ` [PATCH 4/6] cpufreq:amd-pstate: get pstate transition delay and latency value from ACPI tables Perry Yuan
2024-01-31 21:49 ` Mario Limonciello [this message]
2024-01-31 8:50 ` [PATCH 5/6] cppc_acpi: print error message if CPPC is unsupported Perry Yuan
2024-01-31 21:51 ` Mario Limonciello
2024-01-31 8:50 ` [PATCH 6/6] cpufreq:amd-pstate: add quirk for the pstate CPPC capabilities missing Perry Yuan
2024-01-31 21:59 ` Mario Limonciello
2024-02-02 9:05 ` Yuan, Perry
2024-01-31 11:36 ` [PATCH 0/6] AMD Pstate Fixes And Enhancements Tor Vic
2024-02-02 9:12 ` Yuan, Perry
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