Messages in this thread | | | Date | Thu, 21 Apr 2022 07:26:36 +0100 | Subject | Re: [PATCH] arch_topology: Trace the update thermal pressure | From | Lukasz Luba <> |
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On 4/21/22 00:44, Steven Rostedt wrote: > On Tue, 19 Apr 2022 17:48:01 +0100 > Lukasz Luba <lukasz.luba@arm.com> wrote: > >> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c >> index 1d6636ebaac5..4f0392de3081 100644 >> --- a/drivers/base/arch_topology.c >> +++ b/drivers/base/arch_topology.c >> @@ -19,6 +19,8 @@ >> #include <linux/rcupdate.h> >> #include <linux/sched.h> >> >> +#include <trace/events/thermal.h> >> + >> static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); >> static struct cpumask scale_freq_counters_mask; >> static bool scale_freq_invariant; >> @@ -195,6 +197,8 @@ void topology_update_thermal_pressure(const struct cpumask *cpus, >> >> th_pressure = max_capacity - capacity; >> >> + trace_thermal_pressure_update(cpu, th_pressure); >> + >> for_each_cpu(cpu, cpus) >> WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); >> } >> diff --git a/include/trace/events/thermal.h b/include/trace/events/thermal.h >> index 8a5f04888abd..1bf08ee1a25b 100644 >> --- a/include/trace/events/thermal.h >> +++ b/include/trace/events/thermal.h >> @@ -65,6 +65,25 @@ TRACE_EVENT(cdev_update, >> TP_printk("type=%s target=%lu", __get_str(type), __entry->target) >> ); >> >> +TRACE_EVENT(thermal_pressure_update, >> + >> + TP_PROTO(int cpu, unsigned long thermal_pressure), >> + >> + TP_ARGS(cpu, thermal_pressure), >> + >> + TP_STRUCT__entry( >> + __field(int, cpu) >> + __field(unsigned long, thermal_pressure) > > Note, it is always best to place the bigger object before the smaller one > (when not properly aligned), as that will help to prevent structure > "holes". That is: > > __field(unsigned long, thermal_pressure) > __field(int, cpu) > > > Otherwise, you are pretty much guaranteed to have a 4 byte hole between cpu > and thermal_pressure on 64 bit machines. > > Also, for the warning you got from the test robot, if you are using this in > a module and defining it in the core kernel, you need to add: > > EXPORT_TRACEPOINT_SYMBOL_GPL(thermal_pressure_update); > > Somewhere in the C file that includes this file and defines > CREATE_TRACE_POINTS. > > -- Steve > >
Thank you Steve, I'll swap those fields and add the needed export. I have to go through those older trace events in that file and understand if they are correct, since I just followed the pattern in 'cdev_update'.
Regards, Lukasz
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