linux-kernel - Re: [PATCH V1 3/3] ufs: ufs-qcom: Fix sequential read variance

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Message-ID: <4aad22c3-a720-4d88-baa5-aead6854a771@oss.qualcomm.com>
Date: Thu, 22 Jan 2026 16:11:31 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Nitin Rawat <nitin.rawat@....qualcomm.com>, mani@...nel.org,
        James.Bottomley@...senPartnership.com, martin.petersen@...cle.com
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-scsi@...r.kernel.org
Subject: Re: [PATCH V1 3/3] ufs: ufs-qcom: Fix sequential read variance

On 1/22/26 3:13 PM, Nitin Rawat wrote:
> The current devfreq downdifferential threshold of 5% causes overly
> aggressive frequency downscaling, leading to performance degradation
> sometimes during sequential read workloads.
> 
> Update the UFS devfreq downdifferential threshold to 65.
> This widens the hysteresis window and prevents overly aggressive
> downscaling, ensuring that frequency is maintained for loads above 5%
> and scaling down occurs only when utilization falls below this level,
> while scale-up still triggers above the 70% threshold.
> 
> Signed-off-by: Nitin Rawat <nitin.rawat@....qualcomm.com>
> ---
>  drivers/ufs/host/ufs-qcom.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> index ab5aed241913..5ef810b95b72 100644
> --- a/drivers/ufs/host/ufs-qcom.c
> +++ b/drivers/ufs/host/ufs-qcom.c
> @@ -1962,7 +1962,7 @@ static void ufs_qcom_config_scaling_param(struct ufs_hba *hba,
>  	p->polling_ms = 60;
>  	p->timer = DEVFREQ_TIMER_DELAYED;
>  	d->upthreshold = 70;
> -	d->downdifferential = 5;
> +	d->downdifferential = 65;

FWIW I see this is the value that's been shipping on android for 
quite a while 

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad