Messages in this thread | | | Date | Wed, 21 Dec 2022 14:43:39 +0100 | Subject | Re: [RFC][PATCH] thermal/idle_inject: Support 100% idle injection | From | Daniel Lezcano <> |
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Hi Srinivas,
On 09/12/2022 02:36, Srinivas Pandruvada wrote: > The users of idle injection framework allow 100% idle injection. For > example: thermal/cpuidle_cooling.c driver. When the ratio set to 100%, > the runtime_duration becomes zero. > > In the function idle_inject_set_duration() in idle injection framework > run_duration_us == 0 is silently ignored, without any error (it is a > void function). So, the caller will assume that everything is fine and > 100% idle is effective. But in reality the idle inject will be whatever > set before.
Good catch
> There are two options: > - The caller change their max state to 99% instead of 100% and > document that 100% is not supported by idle inject framework > - Support 100% idle support in idle inject framework
Yes, from my POV a CPU being impossible to cool down for any reason should end up by staying off.
> Since there are other protections via RT throttling, this framework can > allow 100% idle. The RT throttling will be activated at 95% idle by > default. The caller disabling RT throttling and injecting 100% idle, > should be aware that CPU can't be used at all.
Would it make sense to write a trace in this case ?
> The idle inject timer is started for (run_duration_us + idle_duration_us) > duration. Hence replace (run_duration_us && idle_duration_us) with > (run_duration_us + idle_duration_us) in the function > idle_inject_set_duration().
Sounds good to me
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > --- > drivers/powercap/idle_inject.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c > index f48e71501429..4a4fe60d2563 100644 > --- a/drivers/powercap/idle_inject.c > +++ b/drivers/powercap/idle_inject.c > @@ -184,7 +184,7 @@ void idle_inject_set_duration(struct idle_inject_device *ii_dev, > unsigned int run_duration_us, > unsigned int idle_duration_us) > { > - if (run_duration_us && idle_duration_us) { > + if (run_duration_us + idle_duration_us) { > WRITE_ONCE(ii_dev->run_duration_us, run_duration_us); > WRITE_ONCE(ii_dev->idle_duration_us, idle_duration_us); > }
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