* Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation
2016-10-11 21:12 [PATCH] cpufreq: CPPC: Correct desired_perf calculation Hoan Tran
@ 2016-10-11 21:50 ` Rafael J. Wysocki
2016-10-11 22:31 ` Hoan Tran
2016-10-12 3:21 ` Viresh Kumar
2016-10-12 15:36 ` Prakash, Prashanth
2 siblings, 1 reply; 6+ messages in thread
From: Rafael J. Wysocki @ 2016-10-11 21:50 UTC (permalink / raw)
To: Hoan Tran
Cc: Viresh Kumar, pprakash, Al Stone, linux-pm, linux-kernel, lho,
Duc Dang
On Tuesday, October 11, 2016 02:12:00 PM 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
>
> Signed-off-by: Hoan Tran <hotran@apm.com>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 1b2f28f..ab1d4b7 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>
> cpu = all_cpu_data[policy->cpu];
>
> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
> freqs.old = policy->cur;
> freqs.new = target_freq;
>
>
This patch has already been applied AFAICS.
Thanks,
Rafael
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation
2016-10-11 21:50 ` Rafael J. Wysocki
@ 2016-10-11 22:31 ` Hoan Tran
0 siblings, 0 replies; 6+ messages in thread
From: Hoan Tran @ 2016-10-11 22:31 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Viresh Kumar, Prashanth Prakash, Al Stone, linux-pm, lkml, Loc Ho,
Duc Dang
Hi Rafael,
On Tue, Oct 11, 2016 at 2:50 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Tuesday, October 11, 2016 02:12:00 PM 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
>>
>> Signed-off-by: Hoan Tran <hotran@apm.com>
>> ---
>> drivers/cpufreq/cppc_cpufreq.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
>> index 1b2f28f..ab1d4b7 100644
>> --- a/drivers/cpufreq/cppc_cpufreq.c
>> +++ b/drivers/cpufreq/cppc_cpufreq.c
>> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>>
>> cpu = all_cpu_data[policy->cpu];
>>
>> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
>> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
>> freqs.old = policy->cur;
>> freqs.new = target_freq;
>>
>>
>
> This patch has already been applied AFAICS.
>
You mean this applied patch "cpufreq: CPPC: Avoid overflow when
calculating desired_perf"
This is another the bug, not the overflow bug.
Thanks
Hoan
> Thanks,
> Rafael
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation
2016-10-11 21:12 [PATCH] cpufreq: CPPC: Correct desired_perf calculation Hoan Tran
2016-10-11 21:50 ` Rafael J. Wysocki
@ 2016-10-12 3:21 ` Viresh Kumar
2016-10-12 15:36 ` Prakash, Prashanth
2 siblings, 0 replies; 6+ messages in thread
From: Viresh Kumar @ 2016-10-12 3:21 UTC (permalink / raw)
To: Hoan Tran
Cc: Rafael J. Wysocki, pprakash, Al Stone, linux-pm, linux-kernel,
lho, Duc Dang
On 11-10-16, 14:12, 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
>
> Signed-off-by: Hoan Tran <hotran@apm.com>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 1b2f28f..ab1d4b7 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>
> cpu = all_cpu_data[policy->cpu];
>
> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
> freqs.old = policy->cur;
> freqs.new = target_freq;
I am not sure what the calculations should be like, but I don't have
any objections against applying this..
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation
2016-10-11 21:12 [PATCH] cpufreq: CPPC: Correct desired_perf calculation Hoan Tran
2016-10-11 21:50 ` Rafael J. Wysocki
2016-10-12 3:21 ` Viresh Kumar
@ 2016-10-12 15:36 ` Prakash, Prashanth
2016-10-12 17:33 ` Hoan Tran
2 siblings, 1 reply; 6+ messages in thread
From: Prakash, Prashanth @ 2016-10-12 15:36 UTC (permalink / raw)
To: Hoan Tran, Rafael J. Wysocki, Viresh Kumar, Al Stone
Cc: linux-pm, linux-kernel, lho, Duc Dang
Hi Hoan,
On 10/11/2016 3:12 PM, 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
>
> Signed-off-by: Hoan Tran <hotran@apm.com>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 1b2f28f..ab1d4b7 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>
> cpu = all_cpu_data[policy->cpu];
>
> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
The patch looks good, I suppose we can add a small optimization. We can do a simple check
to see if the newly computed desired_perf is same as old one, If it is same we can just return
here instead of calling cppc_set_perf with same desired_perf value.
Thanks,
Prashanth
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cpufreq: CPPC: Correct desired_perf calculation
2016-10-12 15:36 ` Prakash, Prashanth
@ 2016-10-12 17:33 ` Hoan Tran
0 siblings, 0 replies; 6+ messages in thread
From: Hoan Tran @ 2016-10-12 17:33 UTC (permalink / raw)
To: Prakash, Prashanth
Cc: Rafael J. Wysocki, Viresh Kumar, Al Stone, linux-pm, lkml, Loc Ho,
Duc Dang
[Resend with plain text mode]
Hi Prashanth,
On Wed, Oct 12, 2016 at 8:36 AM, Prakash, Prashanth
<pprakash@codeaurora.org> wrote:
> Hi Hoan,
>
> On 10/11/2016 3:12 PM, 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
>>
>> Signed-off-by: Hoan Tran <hotran@apm.com>
>> ---
>> drivers/cpufreq/cppc_cpufreq.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
>> index 1b2f28f..ab1d4b7 100644
>> --- a/drivers/cpufreq/cppc_cpufreq.c
>> +++ b/drivers/cpufreq/cppc_cpufreq.c
>> @@ -84,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
>>
>> cpu = all_cpu_data[policy->cpu];
>>
>> - cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
>> + cpu->perf_ctrls.desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
> The patch looks good, I suppose we can add a small optimization. We can do a simple check
> to see if the newly computed desired_perf is same as old one, If it is same we can just return
> here instead of calling cppc_set_perf with same desired_perf value.
That's a good point. I can add a check into this patch.
Thanks
Hoan
>
> Thanks,
> Prashanth
^ permalink raw reply [flat|nested] 6+ messages in thread