Messages in this thread | | | Subject | Re: [RFC][PATCH] thermal/idle_inject: Support 100% idle injection | From | srinivas pandruvada <> | Date | Wed, 21 Dec 2022 12:36:14 -0800 |
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On Wed, 2022-12-21 at 14:43 +0100, Daniel Lezcano wrote: > > 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 ?
There is one printk already: printk_deferred_once("sched: RT throttling activated\n")
You mean we should add
trace_sched_* for this?
> > > 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 > I will submit a patch for this.
Thanks, Srinivas
> > 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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