[tip:sched/core] x86: Add generic aperf/mperf code

tip-bot for Peter Zijlstra
2009-09-16T10:23:40Z

Commit-ID: 5cbc19a983141729d716be17197028434127b376
Gitweb: http://git.kernel.org/tip/5cbc19a983141729d716be17197028434127b376
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Wed, 2 Sep 2009 11:49:52 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 15 Sep 2009 16:51:26 +0200

x86: Add generic aperf/mperf code

Move some of the aperf/mperf code out from the cpufreq driver
thingy so that other people can enjoy it too.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/include/asm/processor.h | 30 +++++++++++
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 79 +++------------------------
2 files changed, 39 insertions(+), 70 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index e08ea04..4ae2ccf 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -27,6 +27,7 @@ struct mm_struct;
#include <linux/cpumask.h>
#include <linux/cache.h>
#include <linux/threads.h>
+#include <linux/math64.h>
#include <linux/init.h>

/*
@@ -1020,4 +1021,33 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
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);
+}
+
+#define APERFMPERF_SHIFT 10
+
+static inline
+unsigned long calc_aperfmperf_ratio(struct aperfmperf *old,
+ struct aperfmperf *new)
+{
+ u64 aperf = new->aperf - old->aperf;
+ u64 mperf = new->mperf - old->mperf;
+ unsigned long ratio = aperf;
+
+ mperf >>= APERFMPERF_SHIFT;
+ if (mperf)
+ ratio = div64_u64(aperf, mperf);
+
+ return ratio;
+}
+
#endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 509e6a7..4109679 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -70,11 +70,7 @@ struct acpi_cpufreq_data {

static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);

-struct acpi_msr_data {
- u64 saved_aperf, saved_mperf;
-};
-
-static DEFINE_PER_CPU(struct acpi_msr_data, msr_data);
+static DEFINE_PER_CPU(struct aperfmperf, old_perf);

DEFINE_TRACE(power_mark);

@@ -243,23 +239,12 @@ static u32 get_cur_val(const struct cpumask *mask)
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);
}

/*
@@ -278,63 +263,17 @@ static void read_measured_perf_ctrs(void *_cur)
static unsigned int get_measured_perf(struct cpufreq_policy *policy,
unsigned int cpu)
{
- struct perf_pair readin, cur;
- unsigned int perf_percent;
+ struct aperfmperf perf;
+ unsigned long ratio;
unsigned int retval;

- if (smp_call_function_single(cpu, read_measured_perf_ctrs, &readin, 1))
+ if (smp_call_function_single(cpu, read_measured_perf_ctrs, &perf, 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;
-
-#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(cur.aperf.split.hi || cur.mperf.split.hi)) {
- int shift_count;
- u32 h;
-
- h = max_t(u32, cur.aperf.split.hi, cur.mperf.split.hi);
- shift_count = fls(h);
-
- cur.aperf.whole >>= shift_count;
- cur.mperf.whole >>= shift_count;
- }
-
- if (((unsigned long)(-1) / 100) < cur.aperf.split.lo) {
- int shift_count = 7;
- cur.aperf.split.lo >>= shift_count;
- cur.mperf.split.lo >>= shift_count;
- }
-
- if (cur.aperf.split.lo && cur.mperf.split.lo)
- perf_percent = (cur.aperf.split.lo * 100) / cur.mperf.split.lo;
- else
- perf_percent = 0;
-
-#else
- if (unlikely(((unsigned long)(-1) / 100) < cur.aperf.whole)) {
- int shift_count = 7;
- cur.aperf.whole >>= shift_count;
- cur.mperf.whole >>= shift_count;
- }
-
- if (cur.aperf.whole && cur.mperf.whole)
- perf_percent = (cur.aperf.whole * 100) / cur.mperf.whole;
- else
- perf_percent = 0;
-
-#endif
+ ratio = calc_aperfmperf_ratio(&per_cpu(old_perf, cpu), &perf);
+ per_cpu(old_perf, cpu) = perf;

- retval = (policy->cpuinfo.max_freq * perf_percent) / 100;
+ retval = (policy->cpuinfo.max_freq * ratio) >> APERFMPERF_SHIFT;

return retval;
}