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Commit 61c63e5e authored by Stratos Karafotis's avatar Stratos Karafotis Committed by Rafael J. Wysocki
Browse files

cpufreq: Remove unused APERF/MPERF support 



The target frequency calculation method in the ondemand governor has
changed and it is now independent of the measured average frequency.
Consequently, the APERF/MPERF support in cpufreq is not used any
more, so drop it.

[rjw: Changelog]
Signed-off-by: default avatarStratos Karafotis <stratosk@semaphore.gr>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent dfa5bb62

arch/x86/include/asm/processor.h

+0 −29
Original line number Diff line number Diff line
@@ -942,35 +942,6 @@ extern int set_tsc_mode(unsigned int val); 


extern u16 amd_get_nb_id(int cpu);



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;

}



extern unsigned long arch_align_stack(unsigned long sp);

extern void free_init_pages(char *what, unsigned long begin, unsigned long end);

drivers/cpufreq/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o 
# powernow-k8 can load then. ACPI is preferred to all other hardware-specific drivers.

# speedstep-* is preferred over p4-clockmod.



obj-$(CONFIG_X86_ACPI_CPUFREQ)		+= acpi-cpufreq.o mperf.o

obj-$(CONFIG_X86_ACPI_CPUFREQ)		+= acpi-cpufreq.o

obj-$(CONFIG_X86_POWERNOW_K8)		+= powernow-k8.o

obj-$(CONFIG_X86_PCC_CPUFREQ)		+= pcc-cpufreq.o

obj-$(CONFIG_X86_POWERNOW_K6)		+= powernow-k6.o

drivers/cpufreq/acpi-cpufreq.c

+0 −5
Original line number Diff line number Diff line
@@ -45,7 +45,6 @@ 
#include <asm/msr.h>

#include <asm/processor.h>

#include <asm/cpufeature.h>

#include "mperf.h"



MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");

MODULE_DESCRIPTION("ACPI Processor P-States Driver");
@@ -861,10 +860,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) 
	/* notify BIOS that we exist */

	acpi_processor_notify_smm(THIS_MODULE);



	/* Check for APERF/MPERF support in hardware */

	if (boot_cpu_has(X86_FEATURE_APERFMPERF))

		acpi_cpufreq_driver.getavg = cpufreq_get_measured_perf;



	pr_debug("CPU%u - ACPI performance management activated.\n", cpu);

	for (i = 0; i < perf->state_count; i++)

		pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",

drivers/cpufreq/mperf.c

deleted100644 → 0
+0 −51
Original line number Diff line number Diff line 
#include <linux/kernel.h>

#include <linux/smp.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/cpufreq.h>

#include <linux/slab.h>



#include "mperf.h"



static DEFINE_PER_CPU(struct aperfmperf, acfreq_old_perf);



/* Called via smp_call_function_single(), on the target CPU */

static void read_measured_perf_ctrs(void *_cur)

{

	struct aperfmperf *am = _cur;



	get_aperfmperf(am);

}



/*

 * Return the measured active (C0) frequency on this CPU since last call

 * to this function.

 * Input: cpu number

 * Return: Average CPU frequency in terms of max frequency (zero on error)

 *

 * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance

 * over a period of time, while CPU is in C0 state.

 * IA32_MPERF counts at the rate of max advertised frequency

 * IA32_APERF counts at the rate of actual CPU frequency

 * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and

 * no meaning should be associated with absolute values of these MSRs.

 */

unsigned int cpufreq_get_measured_perf(struct cpufreq_policy *policy,

					unsigned int cpu)

{

	struct aperfmperf perf;

	unsigned long ratio;

	unsigned int retval;



	if (smp_call_function_single(cpu, read_measured_perf_ctrs, &perf, 1))

		return 0;



	ratio = calc_aperfmperf_ratio(&per_cpu(acfreq_old_perf, cpu), &perf);

	per_cpu(acfreq_old_perf, cpu) = perf;



	retval = (policy->cpuinfo.max_freq * ratio) >> APERFMPERF_SHIFT;



	return retval;

}

EXPORT_SYMBOL_GPL(cpufreq_get_measured_perf);

MODULE_LICENSE("GPL");

drivers/cpufreq/mperf.h

deleted100644 → 0
+0 −9
Original line number Diff line number Diff line 
/*

 *  (c) 2010 Advanced Micro Devices, Inc.

 *  Your use of this code is subject to the terms and conditions of the

 *  GNU general public license version 2. See "COPYING" or

 *  http://www.gnu.org/licenses/gpl.html

 */



unsigned int cpufreq_get_measured_perf(struct cpufreq_policy *policy,

					unsigned int cpu);