Re: [PATCH v1 0/2] cpuidle: teo: Refine handling of short idle intervals

[Aboorva Devarajan <aboorvad@linux.ibm.com>]

On Thu, 2025-04-03 at 21:16 +0200, Rafael J. Wysocki wrote:
> Hi Everyone,
> 
> This series is intended to address an issue with overly aggressive selection
> of idle state 0 (the polling state) in teo on x86 in some cases when timer
> wakeups dominate the CPU wakeup pattern.
> 
> In those cases, timer wakeups are not taken into account when they are
> within the LATENCY_THRESHOLD_NS range and the idle state selection may
> be based entirely on non-timer wakeups which may be rare.  This causes
> the prediction accuracy to be low and too much energy may be used as
> a result.
> 
> The first patch is preparatory and it is not expected to make any
> functional difference.
> 
> The second patch causes teo to take timer wakeups into account if it
> is about to skip the tick_nohz_get_sleep_length() invocation, so they
> get a chance to influence the idle state selection.
> 
> I have been using this series on my systems for several weeks and observed
> a significant reduction of the polling state selection rate in multiple
> workloads.
> 
> Thanks!
> 
> 

Hi Rafael,

I'm running some tests and going through the patch.
I haven't noticed any deviations so far, will post the results shortly.

Thanks,
Aboorva