Re: [RFC][PATCH 10/14] x86: generic aperf/mperf code.

[Thomas Renninger]

On Thursday 03 September 2009 15:21:55 Peter Zijlstra wrote:
> Move some of the aperf/mperf code out from the cpufreq driver thingy
> so that other people can enjoy it too.
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
> Cc: Yanmin <yanmin_zhang@xxxxxxxxxxxxxxx>
> Cc: Dave Jones <davej@xxxxxxxxxx>
> Cc: Len Brown <len.brown@xxxxxxxxx>
> Cc: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
> Cc: cpufreq@xxxxxxxxxxxxxxx
> ---
>  arch/x86/include/asm/processor.h           |   12 ++++++++
>  arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c |   41 
+++++++++--------------------
>  2 files changed, 26 insertions(+), 27 deletions(-)
> 
> Index: linux-2.6/arch/x86/include/asm/processor.h
> ===================================================================
> --- linux-2.6.orig/arch/x86/include/asm/processor.h
> +++ linux-2.6/arch/x86/include/asm/processor.h
> @@ -1000,4 +1000,16 @@ extern void start_thread(struct pt_regs 
>  extern int get_tsc_mode(unsigned long adr);
>  extern int set_tsc_mode(unsigned int val);
>  
> +struct aperfmperf {
> +	u64 aperf, mperf;
> +};
> +
> +static inline void get_aperfmperf(struct aperfmperf *am)
> +{
> +	WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_APERFMPERF));
> +
> +	rdmsrl(MSR_IA32_APERF, am->aperf);
> +	rdmsrl(MSR_IA32_MPERF, am->mperf);
> +}
> +
>  #endif /* _ASM_X86_PROCESSOR_H */
> Index: linux-2.6/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> +++ linux-2.6/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> @@ -243,23 +243,12 @@ static u32 get_cur_val(const struct cpum
>  	return cmd.val;
>  }
>  
> -struct perf_pair {
> -	union {
> -		struct {
> -			u32 lo;
> -			u32 hi;
> -		} split;
> -		u64 whole;
> -	} aperf, mperf;
> -};
> -
>  /* Called via smp_call_function_single(), on the target CPU */
>  static void read_measured_perf_ctrs(void *_cur)
>  {
> -	struct perf_pair *cur = _cur;
> +	struct aperfmperf *am = _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);
> +	get_aperfmperf(am);
>  }
>  
>  /*
> @@ -278,19 +267,17 @@ static void read_measured_perf_ctrs(void
>  static unsigned int get_measured_perf(struct cpufreq_policy *policy,
>  				      unsigned int cpu)
>  {
> -	struct perf_pair readin, cur;
> +	struct aperfmperf readin, cur;
>  	unsigned int perf_percent;
>  	unsigned int retval;
>  
>  	if (smp_call_function_single(cpu, read_measured_perf_ctrs, &readin, 
1))
>  		return 0;
>  
> -	cur.aperf.whole = readin.aperf.whole -
> -				per_cpu(msr_data, cpu).saved_aperf;
> -	cur.mperf.whole = readin.mperf.whole -
> -				per_cpu(msr_data, cpu).saved_mperf;
> -	per_cpu(msr_data, cpu).saved_aperf = readin.aperf.whole;
> -	per_cpu(msr_data, cpu).saved_mperf = readin.mperf.whole;
> +	cur.aperf = readin.aperf - per_cpu(msr_data, cpu).saved_aperf;
> +	cur.mperf = readin.mperf - per_cpu(msr_data, cpu).saved_mperf;
> +	per_cpu(msr_data, cpu).saved_aperf = readin.aperf;
> +	per_cpu(msr_data, cpu).saved_mperf = readin.mperf;
>  
>  #ifdef __i386__
>  	/*
> @@ -305,8 +292,8 @@ static unsigned int get_measured_perf(st
>  		h = max_t(u32, cur.aperf.split.hi, cur.mperf.split.hi);
You still use struct perf_pair split/hi/lo members in #ifdef __i386__ 
case which you deleted above.
>  		shift_count = fls(h);
>  
> -		cur.aperf.whole >>= shift_count;
> -		cur.mperf.whole >>= shift_count;
> +		cur.aperf >>= shift_count;
> +		cur.mperf >>= shift_count;
>  	}
>  
>  	if (((unsigned long)(-1) / 100) < cur.aperf.split.lo) {
Same here, possibly still elsewhere.
Is this only x86_64 compile tested?

     Thomas

> @@ -321,14 +308,14 @@ static unsigned int get_measured_perf(st
>  		perf_percent = 0;
>  
>  #else
> -	if (unlikely(((unsigned long)(-1) / 100) < cur.aperf.whole)) {
> +	if (unlikely(((unsigned long)(-1) / 100) < cur.aperf)) {
>  		int shift_count = 7;
> -		cur.aperf.whole >>= shift_count;
> -		cur.mperf.whole >>= shift_count;
> +		cur.aperf >>= shift_count;
> +		cur.mperf >>= shift_count;
>  	}
>  
> -	if (cur.aperf.whole && cur.mperf.whole)
> -		perf_percent = (cur.aperf.whole * 100) / cur.mperf.whole;
> +	if (cur.aperf && cur.mperf)
> +		perf_percent = (cur.aperf * 100) / cur.mperf;
>  	else
>  		perf_percent = 0;
>  
> 
> -- 
> 
> --
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