Re: [PATCH 0/5] s390/idle: CPU idle driver

[Christian Loehle <christian.loehle@arm.com>]

On 6/9/26 08:52, Mete Durlu wrote:
> This patch series introduces a CPU idle driver for s390
> architecture that leverages the existing cpu idle infrastructure and
> TEO (Timer Events Oriented) governor to optimize idle state selection
> based on timer events and interrupt patterns.
> 
> # Implementation Overview
> -----------------------------------------------------------------------
> 
> The driver implements two idle states;
> 
> **Polling Idle (shallow state)**
> - Busy-loop implementation that prevents SIE-exit during short idle periods
> - Zero exit latency, optimized for latency-sensitive workloads
> - Maintains CPU with the guest, improving response times
> 
> **Enabled Wait (deep state)**
> - Traditional EW state that signals hypervisor availability
> - Higher exit latency but more efficient for longer idle periods
> 
> The TEO governor dynamically selects between these states by monitoring
> next timer interrupts and system interrupt frequency, choosing the most
> appropriate idle state for each situation.
> 
I don't quite get the TEO focus of this series, on principle menu works
similarly, did TEO just work much better for you?
If so do you know why?