Re: [patch 2/2] acpi x86: Make aperf/mperf MSR access in acpi_cpufreq read_only

[Len Brown <lenb@kernel.org>]

applied

(and cpufreq@vger.kernel.org cc'd)

thanks,
Len Brown, Intel Open Source Technology Center

On Mon, 6 Apr 2009, venkatesh.pallipadi@intel.com wrote:

> Not write zeroes to APERF and MPERF by ondemand governor. With this
> change, other users can share these MSRs for reads.
> 
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
> ---
>  arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c |   15 ++++++++++-----
>  1 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> index 340bdbe..9d3af38 100644
> --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> @@ -68,6 +68,7 @@ struct acpi_cpufreq_data {
>  	unsigned int max_freq;
>  	unsigned int resume;
>  	unsigned int cpu_feature;
> +	u64 saved_aperf, saved_mperf;
>  };
>  
>  static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
> @@ -259,9 +260,6 @@ static long read_measured_perf_ctrs(void *_cur)
>  	rdmsr(MSR_IA32_APERF, cur->aperf.split.lo, cur->aperf.split.hi);
>  	rdmsr(MSR_IA32_MPERF, cur->mperf.split.lo, cur->mperf.split.hi);
>  
> -	wrmsr(MSR_IA32_APERF, 0, 0);
> -	wrmsr(MSR_IA32_MPERF, 0, 0);
> -
>  	return 0;
>  }
>  
> @@ -281,13 +279,20 @@ static long read_measured_perf_ctrs(void *_cur)
>  static unsigned int get_measured_perf(struct cpufreq_policy *policy,
>  				      unsigned int cpu)
>  {
> -	struct perf_pair cur;
> +	struct perf_pair readin, cur;
>  	unsigned int perf_percent;
>  	unsigned int retval;
>  
> -	if (!work_on_cpu(cpu, read_measured_perf_ctrs, &cur))
> +	if (!work_on_cpu(cpu, read_measured_perf_ctrs, &readin))
>  		return 0;
>  
> +	cur.aperf.whole = readin.aperf.whole -
> +				per_cpu(drv_data, cpu)->saved_aperf;
> +	cur.mperf.whole = readin.mperf.whole -
> +				per_cpu(drv_data, cpu)->saved_mperf;
> +	per_cpu(drv_data, cpu)->saved_aperf = readin.aperf.whole;
> +	per_cpu(drv_data, cpu)->saved_mperf = readin.mperf.whole;
> +
>  #ifdef __i386__
>  	/*
>  	 * We dont want to do 64 bit divide with 32 bit kernel
> -- 
> 1.6.0.6
> 
> -- 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>