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Commit f14a1396 authored by Jacob Pan's avatar Jacob Pan Committed by Rafael J. Wysocki
Browse files

powercap/rapl: reduce ipi calls 



Reduce remote CPU calls for MSR access by combining read
modify write into one function.

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 16ccbd87

drivers/powercap/intel_rapl.c

+85 −34
Original line number Diff line number Diff line
@@ -133,6 +133,12 @@ struct rapl_domain_data { 
	unsigned long timestamp;

};



struct msrl_action {

	u32 msr_no;

	u64 clear_mask;

	u64 set_mask;

	int err;

};



#define	DOMAIN_STATE_INACTIVE           BIT(0)

#define	DOMAIN_STATE_POWER_LIMIT_SET    BIT(1)
@@ -800,35 +806,62 @@ static int rapl_read_data_raw(struct rapl_domain *rd, 
	return 0;

}





static int msrl_update_safe(u32 msr_no, u64 clear_mask, u64 set_mask)

{

	int err;

	u64 val;



	err = rdmsrl_safe(msr_no, &val);

	if (err)

		goto out;



	val &= ~clear_mask;

	val |= set_mask;



	err = wrmsrl_safe(msr_no, val);



out:

	return err;

}



static void msrl_update_func(void *info)

{

	struct msrl_action *ma = info;



	ma->err = msrl_update_safe(ma->msr_no, ma->clear_mask, ma->set_mask);

}



/* Similar use of primitive info in the read counterpart */

static int rapl_write_data_raw(struct rapl_domain *rd,

			enum rapl_primitives prim,

			unsigned long long value)

{

	u64 msr_val;

	u32 msr;

	struct rapl_primitive_info *rp = &rpi[prim];

	int cpu;

	u64 bits;

	struct msrl_action ma;

	int ret;



	cpu = find_active_cpu_on_package(rd->package_id);

	if (cpu < 0)

		return cpu;

	msr = rd->msrs[rp->id];

	if (rdmsrl_safe_on_cpu(cpu, msr, &msr_val)) {

		dev_dbg(&rd->power_zone.dev,

			"failed to read msr 0x%x on cpu %d\n", msr, cpu);

		return -EIO;

	}

	value = rapl_unit_xlate(rd, rd->package_id, rp->unit, value, 1);

	msr_val &= ~rp->mask;

	msr_val |= value << rp->shift;

	if (wrmsrl_safe_on_cpu(cpu, msr, msr_val)) {

		dev_dbg(&rd->power_zone.dev,

			"failed to write msr 0x%x on cpu %d\n", msr, cpu);

		return -EIO;

	}



	return 0;

	bits = rapl_unit_xlate(rd, rd->package_id, rp->unit, value, 1);

	bits |= bits << rp->shift;

	memset(&ma, 0, sizeof(ma));



	ma.msr_no = rd->msrs[rp->id];

	ma.clear_mask = rp->mask;

	ma.set_mask = bits;



	ret = smp_call_function_single(cpu, msrl_update_func, &ma, 1);

	if (ret)

		WARN_ON_ONCE(ret);

	else

		ret = ma.err;



	return ret;

}



/*
@@ -893,6 +926,21 @@ static int rapl_check_unit_atom(struct rapl_package *rp, int cpu) 
	return 0;

}



static void power_limit_irq_save_cpu(void *info)

{

	u32 l, h = 0;

	struct rapl_package *rp = (struct rapl_package *)info;



	/* save the state of PLN irq mask bit before disabling it */

	rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);

	if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED)) {

		rp->power_limit_irq = l & PACKAGE_THERM_INT_PLN_ENABLE;

		rp->power_limit_irq |= PACKAGE_PLN_INT_SAVED;

	}

	l &= ~PACKAGE_THERM_INT_PLN_ENABLE;

	wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);

}





/* REVISIT:

 * When package power limit is set artificially low by RAPL, LVT
@@ -906,7 +954,6 @@ static int rapl_check_unit_atom(struct rapl_package *rp, int cpu) 


static void package_power_limit_irq_save(int package_id)

{

	u32 l, h = 0;

	int cpu;

	struct rapl_package *rp;
@@ -920,20 +967,30 @@ static void package_power_limit_irq_save(int package_id) 
	cpu = find_active_cpu_on_package(package_id);

	if (cpu < 0)

		return;

	/* save the state of PLN irq mask bit before disabling it */

	rdmsr_safe_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);

	if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED)) {

		rp->power_limit_irq = l & PACKAGE_THERM_INT_PLN_ENABLE;

		rp->power_limit_irq |= PACKAGE_PLN_INT_SAVED;

	if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))

		return;



	smp_call_function_single(cpu, power_limit_irq_save_cpu, rp, 1);

}



static void power_limit_irq_restore_cpu(void *info)

{

	u32 l, h = 0;

	struct rapl_package *rp = (struct rapl_package *)info;



	rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);



	if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)

		l |= PACKAGE_THERM_INT_PLN_ENABLE;

	else

		l &= ~PACKAGE_THERM_INT_PLN_ENABLE;

	wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);



	wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);

}



/* restore per package power limit interrupt enable state */

static void package_power_limit_irq_restore(int package_id)

{

	u32 l, h;

	int cpu;

	struct rapl_package *rp;
@@ -951,14 +1008,8 @@ static void package_power_limit_irq_restore(int package_id) 
	/* irq enable state not saved, nothing to restore */

	if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED))

		return;

	rdmsr_safe_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);



	if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)

		l |= PACKAGE_THERM_INT_PLN_ENABLE;

	else

		l &= ~PACKAGE_THERM_INT_PLN_ENABLE;



	wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);

	smp_call_function_single(cpu, power_limit_irq_restore_cpu, rp, 1);

}



static void set_floor_freq_default(struct rapl_domain *rd, bool mode)