Re: [PATCH v3] soc: qcom: icc-bwmon: Update zone1_thres_count to 3
From: Krzysztof Kozlowski
Date: Sat Feb 28 2026 - 04:49:22 EST
On 27/02/2026 12:10, Pushpendra Singh wrote:
> From: Shivnandan Kumar <quic_kshivnan@xxxxxxxxxxx>
>
> Reduce zone1_thres_count from 16 to 3 so the driver can lower the bus
> vote after 3 sample windows instead of waiting for 16. The previous
> 16‑window delay (~64 ms) is too long at higher FPS workloads,
> causing delayed decision making and measurable power regression.
>
> Empirical tuning showed that lower values (e.g., 2) made bwmon behavior
> jittery, while higher values (4–6) were stable but less responsive and
> reduced power savings. A value of 3 provided the best balance: responsive
> enough for timely power reduction while maintaining stable bwmon
> operation.
>
> Significant power savings were observed across multiple use cases when
> reducing the threshold from 16 to 3:
>
> USECASE zone1_thres_count=16 zone1_thres_count=3
> 4K video playback 236.15 mA 203.15 mA
> Sleep 7mA 6.9mA
> Display (idle display) 71.95mA 67.11mA
Which hardware exactly? Which kernel?
You keep running this on downstream, like a lot of code from Qualcomm
and speeches on conferences, so I just don't trust the numbers.
Best regards,
Krzysztof