diff mbox series

[v2,1/2] scsi: ufs: Suspend clk scaling on no request

Message ID 20240627083756.25340-2-quic_rampraka@quicinc.com (mailing list archive)
State Accepted
Headers show
Series Suspend clk scaling when there is no request | expand

Commit Message

Ram Prakash Gupta June 27, 2024, 8:37 a.m. UTC
Currently ufs clk scaling is getting suspended only when the
clks are scaled down, but next when high load is generated its
adding a huge amount of latency in scaling up the clk and complete
the request post that.

Now if the scaling is suspended in its existing state, and when high
load is generated it is helping improve the random performance KPI by
28%. So suspending the scaling when there is no request. And the clk
would be put in low scaled state when the actual request load is low.

Making this change as optional for other vendor by having the check
enabled using vops as for some vendor suspending without bringing the
clk in low scaled state might have impact on power consumption on the
SoC.

Signed-off-by: Ram Prakash Gupta <quic_rampraka@quicinc.com>
---
 drivers/ufs/core/ufshcd.c | 3 ++-
 include/ufs/ufshcd.h      | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

Comments

Bart Van Assche June 27, 2024, 4:35 p.m. UTC | #1
On 6/27/24 1:37 AM, Ram Prakash Gupta wrote:
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 1b65e6ae4137..9f935e5c60e8 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -1560,7 +1560,8 @@ static int ufshcd_devfreq_target(struct device *dev,
>   		ktime_to_us(ktime_sub(ktime_get(), start)), ret);
>   
>   out:
> -	if (sched_clk_scaling_suspend_work && !scale_up)
> +	if (sched_clk_scaling_suspend_work &&
> +			(!scale_up || hba->clk_scaling.suspend_on_no_request))
>   		queue_work(hba->clk_scaling.workq,
>   			   &hba->clk_scaling.suspend_work);
>   
> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
> index bad88bd91995..c14607f2890b 100644
> --- a/include/ufs/ufshcd.h
> +++ b/include/ufs/ufshcd.h
> @@ -457,6 +457,7 @@ struct ufs_clk_scaling {
>   	bool is_initialized;
>   	bool is_busy_started;
>   	bool is_suspended;
> +	bool suspend_on_no_request;
>   };
>   
>   #define UFS_EVENT_HIST_LENGTH 8

Who are the other vendors that support clock scaling? I'm asking because
I don't think that the behavior change introduced by this patch should
depend on the SoC vendor.

Thanks,

Bart.
Ram Prakash Gupta June 27, 2024, 4:59 p.m. UTC | #2
On 6/27/2024 10:05 PM, Bart Van Assche wrote:
> On 6/27/24 1:37 AM, Ram Prakash Gupta wrote:
>> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
>> index 1b65e6ae4137..9f935e5c60e8 100644
>> --- a/drivers/ufs/core/ufshcd.c
>> +++ b/drivers/ufs/core/ufshcd.c
>> @@ -1560,7 +1560,8 @@ static int ufshcd_devfreq_target(struct device 
>> *dev,
>>           ktime_to_us(ktime_sub(ktime_get(), start)), ret);
>>   out:
>> -    if (sched_clk_scaling_suspend_work && !scale_up)
>> +    if (sched_clk_scaling_suspend_work &&
>> +            (!scale_up || hba->clk_scaling.suspend_on_no_request))
>>           queue_work(hba->clk_scaling.workq,
>>                  &hba->clk_scaling.suspend_work);
>> diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
>> index bad88bd91995..c14607f2890b 100644
>> --- a/include/ufs/ufshcd.h
>> +++ b/include/ufs/ufshcd.h
>> @@ -457,6 +457,7 @@ struct ufs_clk_scaling {
>>       bool is_initialized;
>>       bool is_busy_started;
>>       bool is_suspended;
>> +    bool suspend_on_no_request;
>>   };
>>   #define UFS_EVENT_HIST_LENGTH 8
> 
> Who are the other vendors that support clock scaling? I'm asking because
> I don't think that the behavior change introduced by this patch should
> depend on the SoC vendor.
> 
> Thanks,
> 
> Bart.

Hi Bart,

I guess, Mediatek is one vendor who is having this feature in use as I
see some fixes coming from Peter with respect to clk scaling, where some
power regression on mediatek chipsets were addressed.

Please check below link for background of this change and reason to keep
it vendor specific.
https://www.spinics.net/lists/linux-scsi/msg193591.html

Thanks,
Ram
diff mbox series

Patch

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 1b65e6ae4137..9f935e5c60e8 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1560,7 +1560,8 @@  static int ufshcd_devfreq_target(struct device *dev,
 		ktime_to_us(ktime_sub(ktime_get(), start)), ret);
 
 out:
-	if (sched_clk_scaling_suspend_work && !scale_up)
+	if (sched_clk_scaling_suspend_work &&
+			(!scale_up || hba->clk_scaling.suspend_on_no_request))
 		queue_work(hba->clk_scaling.workq,
 			   &hba->clk_scaling.suspend_work);
 
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index bad88bd91995..c14607f2890b 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -457,6 +457,7 @@  struct ufs_clk_scaling {
 	bool is_initialized;
 	bool is_busy_started;
 	bool is_suspended;
+	bool suspend_on_no_request;
 };
 
 #define UFS_EVENT_HIST_LENGTH 8