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Subject[PATCH 5/6] acpi_cpufreq: Use centralized APERF/MPERF function calls
Date
Now that we've centralized APERF/MPERF accessor functions and hooked up
the chargeback accounting code to it, convert the only other user of the
APERF/MPERF MSRs to use those functions as well.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 73 +++++-----------------------
1 files changed, 14 insertions(+), 59 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 8e48c5d..21958af 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -57,7 +57,6 @@ enum {
};

#define INTEL_MSR_RANGE (0xffff)
-#define CPUID_6_ECX_APERFMPERF_CAPABILITY (0x1)

struct acpi_cpufreq_data {
struct acpi_processor_performance *acpi_data;
@@ -243,6 +242,9 @@ static u32 get_cur_val(const cpumask_t *mask)
return cmd.val;
}

+DEFINE_PER_CPU(u64, cpufreq_old_aperf);
+DEFINE_PER_CPU(u64, cpufreq_old_mperf);
+
/*
* Return the measured active (C0) frequency on this CPU since last call
* to this function.
@@ -259,16 +261,8 @@ static u32 get_cur_val(const cpumask_t *mask)
static unsigned int get_measured_perf(struct cpufreq_policy *policy,
unsigned int cpu)
{
- union {
- struct {
- u32 lo;
- u32 hi;
- } split;
- u64 whole;
- } aperf_cur, mperf_cur;
-
+ u64 aperf_cur, mperf_cur;
cpumask_t saved_mask;
- unsigned int perf_percent;
unsigned int retval;

saved_mask = current->cpus_allowed;
@@ -279,60 +273,21 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy,
return 0;
}

- rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
- rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
-
- wrmsr(MSR_IA32_APERF, 0,0);
- wrmsr(MSR_IA32_MPERF, 0,0);
-
-#ifdef __i386__
- /*
- * We dont want to do 64 bit divide with 32 bit kernel
- * Get an approximate value. Return failure in case we cannot get
- * an approximate value.
- */
- if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {
- int shift_count;
- u32 h;
-
- h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);
- shift_count = fls(h);
-
- aperf_cur.whole >>= shift_count;
- mperf_cur.whole >>= shift_count;
- }
-
- if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {
- int shift_count = 7;
- aperf_cur.split.lo >>= shift_count;
- mperf_cur.split.lo >>= shift_count;
- }
-
- if (aperf_cur.split.lo && mperf_cur.split.lo)
- perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;
- else
- perf_percent = 0;
-
-#else
- if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {
- int shift_count = 7;
- aperf_cur.whole >>= shift_count;
- mperf_cur.whole >>= shift_count;
- }
-
- if (aperf_cur.whole && mperf_cur.whole)
- perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;
- else
- perf_percent = 0;
-
-#endif
+ /* Calculate difference in APERF and MPERF. */
+ get_intel_aperf_mperf_registers(&aperf_cur, &mperf_cur);
+ aperf_cur = delta_perf(aperf_cur, &(per_cpu(cpufreq_old_aperf,
+ smp_processor_id())));
+ mperf_cur = delta_perf(mperf_cur, &(per_cpu(cpufreq_old_mperf,
+ smp_processor_id())));

- retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100;
+ /* Scale CPU frequency according to APERF/MPERF. */
+ retval = scale_with_perf(per_cpu(drv_data, policy->cpu)->max_freq,
+ aperf_cur, mperf_cur);

put_cpu();
set_cpus_allowed_ptr(current, &saved_mask);

- dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);
+ dprintk("cpu %d: performance freq %d\n", cpu, retval);
return retval;
}



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