Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1500477 > unrolled thread

[PATCH v2] cpufreq: CPPC: Correct desired_perf calculation

Started byHoan Tran <hotran@apm.com>
First post2016-10-13 19:50 +0200
Last post2016-10-13 23:30 +0200
Articles 4 — 3 participants

Back to article view | Back to linux.kernel

Contents

  [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation Hoan Tran <hotran@apm.com> - 2016-10-13 19:50 +0200
    Re: [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation "Prakash, Prashanth" <pprakash@codeaurora.org> - 2016-10-13 21:50 +0200
      Re: [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation "Rafael J. Wysocki" <rafael@kernel.org> - 2016-10-13 23:20 +0200
        Re: [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation Hoan Tran <hotran@apm.com> - 2016-10-13 23:30 +0200

#1500477 — [PATCH v2] cpufreq: CPPC: Correct desired_perf calculation

FromHoan Tran <hotran@apm.com>
Date2016-10-13 19:50 +0200
Subject[PATCH v2] cpufreq: CPPC: Correct desired_perf calculation
Message-ID<srSiJ-6F7-13@gated-at.bofh.it>
The desired_perf is an abstract performance number. Its value should
be in the range of [lowest perf, highest perf] of CPPC.
The correct calculation is
  desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz

And cppc_cpufreq_set_target() returns if desired_perf is exactly
the same with the old perf.

Signed-off-by: Hoan Tran <hotran@apm.com>
---
v2
 * Return if desired_perf is the same with the old one (Prashanth's suggestion)


 drivers/cpufreq/cppc_cpufreq.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 1b2f28f..4852d9e 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -80,11 +80,17 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 {
 	struct cppc_cpudata *cpu;
 	struct cpufreq_freqs freqs;
+	u32 desired_perf;
 	int ret = 0;
 
 	cpu = all_cpu_data[policy->cpu];
 
-	cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
+	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
+	/* Return if it is exactly the same perf */
+	if (desired_perf == cpu->perf_ctrls.desired_perf)
+		return ret;
+
+	cpu->perf_ctrls.desired_perf = desired_perf;
 	freqs.old = policy->cur;
 	freqs.new = target_freq;
 
-- 
1.9.1

[toc] | [next] | [standalone]

#1500519

From"Prakash, Prashanth" <pprakash@codeaurora.org>
Date2016-10-13 21:50 +0200
Message-ID<srUaR-7SK-11@gated-at.bofh.it>
In reply to#1500477
On 10/13/2016 11:33 AM, Hoan Tran wrote:
> The desired_perf is an abstract performance number. Its value should
> be in the range of [lowest perf, highest perf] of CPPC.
> The correct calculation is
>   desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz
>
> And cppc_cpufreq_set_target() returns if desired_perf is exactly
> the same with the old perf.
>
> Signed-off-by: Hoan Tran <hotran@apm.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>

Hi Rafael,
Can you please pick this one for 4.9, as it is bug fix?

--
Thanks,
Prashanth

[toc] | [prev] | [next] | [standalone]

#1500577

From"Rafael J. Wysocki" <rafael@kernel.org>
Date2016-10-13 23:20 +0200
Message-ID<srVzY-qJ-25@gated-at.bofh.it>
In reply to#1500519
On Thu, Oct 13, 2016 at 9:37 PM, Prakash, Prashanth
<pprakash@codeaurora.org> wrote:
> On 10/13/2016 11:33 AM, Hoan Tran wrote:
>> The desired_perf is an abstract performance number. Its value should
>> be in the range of [lowest perf, highest perf] of CPPC.
>> The correct calculation is
>>   desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz
>>
>> And cppc_cpufreq_set_target() returns if desired_perf is exactly
>> the same with the old perf.
>>
>> Signed-off-by: Hoan Tran <hotran@apm.com>
> Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
>
> Hi Rafael,
> Can you please pick this one for 4.9, as it is bug fix?

Sure, I will queue it up.

Thanks,
Rafael

[toc] | [prev] | [next] | [standalone]

#1500583

FromHoan Tran <hotran@apm.com>
Date2016-10-13 23:30 +0200
Message-ID<srVJD-u5-13@gated-at.bofh.it>
In reply to#1500577
On Thu, Oct 13, 2016 at 2:12 PM, Rafael J. Wysocki <rafael@kernel.org> wrote:
> On Thu, Oct 13, 2016 at 9:37 PM, Prakash, Prashanth
> <pprakash@codeaurora.org> wrote:
>> On 10/13/2016 11:33 AM, Hoan Tran wrote:
>>> The desired_perf is an abstract performance number. Its value should
>>> be in the range of [lowest perf, highest perf] of CPPC.
>>> The correct calculation is
>>>   desired_perf = freq * cppc_highest_perf / cppc_dmi_max_khz
>>>
>>> And cppc_cpufreq_set_target() returns if desired_perf is exactly
>>> the same with the old perf.
>>>
>>> Signed-off-by: Hoan Tran <hotran@apm.com>
>> Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
>>
>> Hi Rafael,
>> Can you please pick this one for 4.9, as it is bug fix?
>
> Sure, I will queue it up.
>

Thanks, Rafael and Prashanth !

Hoan

> Thanks,
> Rafael

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web