Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 20 Jan 2023 18:30:15 +0100 | Subject | Re: [PATCH] thermal/idle_inject: Support 100% idle injection |
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It's powercap/idle_inject.
On Tue, Jan 17, 2023 at 7:23 PM Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> 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. > > 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 > > 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. > > 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(). Also check for !(run_duration_us + > idle_duration_us) to return -EINVAL in the function idle_inject_start().
And I have edited the changelog somewhat.
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > --- > Change log: > Compared to RFC/RFT > - Add a pr_debug for 100% idle > > drivers/powercap/idle_inject.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c > index c57b40477246..3ac81086d71f 100644 > --- a/drivers/powercap/idle_inject.c > +++ b/drivers/powercap/idle_inject.c > @@ -170,10 +170,12 @@ 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); > } > + if (!run_duration_us) > + pr_debug("CPU is forced to 100 percent idle\n"); > } > EXPORT_SYMBOL_NS_GPL(idle_inject_set_duration, IDLE_INJECT); > > @@ -219,7 +221,7 @@ int idle_inject_start(struct idle_inject_device *ii_dev) > unsigned int idle_duration_us = READ_ONCE(ii_dev->idle_duration_us); > unsigned int run_duration_us = READ_ONCE(ii_dev->run_duration_us); > > - if (!idle_duration_us || !run_duration_us) > + if (!(idle_duration_us + run_duration_us)) > return -EINVAL; > > pr_debug("Starting injecting idle cycles on CPUs '%*pbl'\n", > --
Applied as 6.3 material, thanks!
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