Re: PATCH] ftrace: Add a C/P state tracer to help power optimization

[Frank Ch. Eigler]

Arjan van de Ven <arjan@xxxxxxxxxxxxx> writes:

> [...]
> --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> [...]
> @@ -427,6 +429,8 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
>  		}
>  	}
>  
> +	trace_power_mark(&it, POWER_PSTATE, next_perf_state);
> +
>  	switch (data->cpu_feature) {
>  	case SYSTEM_INTEL_MSR_CAPABLE:
>  		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
> [...]

Is there some reason that this doesn't use tracepoints instead
of such a single-backend hook?


- FChE
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