[PATCH v4 2/2] powercap/rapl: reduce ipi calls
From: Jacob Pan
Date: Fri Feb 19 2016 - 15:39:24 EST
Reduce remote CPU calls for MSR access by combining read
modify write into one function. Also optimize calling active CPU on
package by tracking a lead cpu for each package.
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
drivers/powercap/intel_rapl.c | 224 ++++++++++++++++++++++--------------------
1 file changed, 118 insertions(+), 106 deletions(-)
diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index 6c592dc..a492366 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -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)
@@ -149,6 +155,7 @@ struct rapl_power_limit {
static const char pl1_name[] = "long_term";
static const char pl2_name[] = "short_term";
+struct rapl_package;
struct rapl_domain {
const char *name;
enum rapl_domain_type id;
@@ -159,7 +166,7 @@ struct rapl_domain {
u64 attr_map; /* track capabilities */
unsigned int state;
unsigned int domain_energy_unit;
- int package_id;
+ struct rapl_package *rp;
};
#define power_zone_to_rapl_domain(_zone) \
container_of(_zone, struct rapl_domain, power_zone)
@@ -184,6 +191,7 @@ struct rapl_package {
* notify interrupt enable status.
*/
struct list_head plist;
+ int lead_cpu; /* one active cpu per package for access */
};
struct rapl_defaults {
@@ -231,10 +239,10 @@ static int rapl_read_data_raw(struct rapl_domain *rd,
static int rapl_write_data_raw(struct rapl_domain *rd,
enum rapl_primitives prim,
unsigned long long value);
-static u64 rapl_unit_xlate(struct rapl_domain *rd, int package,
+static u64 rapl_unit_xlate(struct rapl_domain *rd,
enum unit_type type, u64 value,
int to_raw);
-static void package_power_limit_irq_save(int package_id);
+static void package_power_limit_irq_save(struct rapl_package *rp);
static LIST_HEAD(rapl_packages); /* guarded by CPU hotplug lock */
@@ -260,20 +268,6 @@ static struct rapl_package *find_package_by_id(int id)
return NULL;
}
-/* caller to ensure CPU hotplug lock is held */
-static int find_active_cpu_on_package(int package_id)
-{
- int i;
-
- for_each_online_cpu(i) {
- if (topology_physical_package_id(i) == package_id)
- return i;
- }
- /* all CPUs on this package are offline */
-
- return -ENODEV;
-}
-
/* caller must hold cpu hotplug lock */
static void rapl_cleanup_data(void)
{
@@ -312,25 +306,19 @@ static int get_max_energy_counter(struct powercap_zone *pcd_dev, u64 *energy)
{
struct rapl_domain *rd = power_zone_to_rapl_domain(pcd_dev);
- *energy = rapl_unit_xlate(rd, 0, ENERGY_UNIT, ENERGY_STATUS_MASK, 0);
+ *energy = rapl_unit_xlate(rd, ENERGY_UNIT, ENERGY_STATUS_MASK, 0);
return 0;
}
static int release_zone(struct powercap_zone *power_zone)
{
struct rapl_domain *rd = power_zone_to_rapl_domain(power_zone);
- struct rapl_package *rp;
+ struct rapl_package *rp = rd->rp;
/* package zone is the last zone of a package, we can free
* memory here since all children has been unregistered.
*/
if (rd->id == RAPL_DOMAIN_PACKAGE) {
- rp = find_package_by_id(rd->package_id);
- if (!rp) {
- dev_warn(&power_zone->dev, "no package id %s\n",
- rd->name);
- return -ENODEV;
- }
kfree(rd);
rp->domains = NULL;
}
@@ -432,11 +420,7 @@ static int set_power_limit(struct powercap_zone *power_zone, int id,
get_online_cpus();
rd = power_zone_to_rapl_domain(power_zone);
- rp = find_package_by_id(rd->package_id);
- if (!rp) {
- ret = -ENODEV;
- goto set_exit;
- }
+ rp = rd->rp;
if (rd->state & DOMAIN_STATE_BIOS_LOCKED) {
dev_warn(&power_zone->dev, "%s locked by BIOS, monitoring only\n",
@@ -456,7 +440,7 @@ static int set_power_limit(struct powercap_zone *power_zone, int id,
ret = -EINVAL;
}
if (!ret)
- package_power_limit_irq_save(rd->package_id);
+ package_power_limit_irq_save(rp);
set_exit:
put_online_cpus();
return ret;
@@ -655,24 +639,19 @@ static void rapl_init_domains(struct rapl_package *rp)
break;
}
if (mask) {
- rd->package_id = rp->id;
+ rd->rp = rp;
rd++;
}
}
}
-static u64 rapl_unit_xlate(struct rapl_domain *rd, int package,
- enum unit_type type, u64 value,
- int to_raw)
+static u64 rapl_unit_xlate(struct rapl_domain *rd, enum unit_type type,
+ u64 value, int to_raw)
{
u64 units = 1;
- struct rapl_package *rp;
+ struct rapl_package *rp = rd->rp;
u64 scale = 1;
- rp = find_package_by_id(package);
- if (!rp)
- return value;
-
switch (type) {
case POWER_UNIT:
units = rp->power_unit;
@@ -769,10 +748,8 @@ static int rapl_read_data_raw(struct rapl_domain *rd,
msr = rd->msrs[rp->id];
if (!msr)
return -EINVAL;
- /* use physical package id to look up active cpus */
- cpu = find_active_cpu_on_package(rd->package_id);
- if (cpu < 0)
- return cpu;
+
+ cpu = rd->rp->lead_cpu;
/* special-case package domain, which uses a different bit*/
if (prim == FW_LOCK && rd->id == RAPL_DOMAIN_PACKAGE) {
@@ -793,42 +770,66 @@ static int rapl_read_data_raw(struct rapl_domain *rd,
final = value & rp->mask;
final = final >> rp->shift;
if (xlate)
- *data = rapl_unit_xlate(rd, rd->package_id, rp->unit, final, 0);
+ *data = rapl_unit_xlate(rd, rp->unit, final, 0);
else
*data = final;
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;
- }
+ cpu = rd->rp->lead_cpu;
+ bits = rapl_unit_xlate(rd, rp->unit, value, 1);
+ bits |= bits << rp->shift;
+ memset(&ma, 0, sizeof(ma));
- return 0;
+ 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 +894,21 @@ 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
@@ -904,61 +920,40 @@ static int rapl_check_unit_atom(struct rapl_package *rp, int cpu)
* to do by adding an atomic notifier.
*/
-static void package_power_limit_irq_save(int package_id)
+static void package_power_limit_irq_save(struct rapl_package *rp)
{
- u32 l, h = 0;
- int cpu;
- struct rapl_package *rp;
-
- rp = find_package_by_id(package_id);
- if (!rp)
- return;
-
if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
return;
- 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;
- }
- l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
- wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+ smp_call_function_single(rp->lead_cpu, power_limit_irq_save_cpu, rp, 1);
}
-/* restore per package power limit interrupt enable state */
-static void package_power_limit_irq_restore(int package_id)
+static void power_limit_irq_restore_cpu(void *info)
{
- u32 l, h;
- int cpu;
- struct rapl_package *rp;
+ u32 l, h = 0;
+ struct rapl_package *rp = (struct rapl_package *)info;
- rp = find_package_by_id(package_id);
- if (!rp)
- return;
+ rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
- if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
- return;
+ if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)
+ l |= PACKAGE_THERM_INT_PLN_ENABLE;
+ else
+ l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
+
+ wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+}
- cpu = find_active_cpu_on_package(package_id);
- if (cpu < 0)
+/* restore per package power limit interrupt enable state */
+static void package_power_limit_irq_restore(struct rapl_package *rp)
+{
+ if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
return;
/* 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(rp->lead_cpu, power_limit_irq_restore_cpu, rp, 1);
}
static void set_floor_freq_default(struct rapl_domain *rd, bool mode)
@@ -1141,7 +1136,7 @@ static int rapl_unregister_powercap(void)
* hotplug lock held
*/
list_for_each_entry(rp, &rapl_packages, plist) {
- package_power_limit_irq_restore(rp->id);
+ package_power_limit_irq_restore(rp);
for (rd = rp->domains; rd < rp->domains + rp->nr_domains;
rd++) {
@@ -1380,6 +1375,7 @@ static int rapl_detect_topology(void)
int i;
int phy_package_id;
struct rapl_package *new_package, *rp;
+ int lead_cpu;
for_each_online_cpu(i) {
phy_package_id = topology_physical_package_id(i);
@@ -1392,7 +1388,11 @@ static int rapl_detect_topology(void)
/* add the new package to the list */
new_package->id = phy_package_id;
new_package->nr_cpus = 1;
-
+ /* find the first active cpu of the package */
+ lead_cpu = cpumask_any_and(topology_core_cpumask(i),
+ cpumask_of(i));
+ if (lead_cpu < nr_cpu_ids)
+ new_package->lead_cpu = lead_cpu;
/* check if the package contains valid domains */
if (rapl_detect_domains(new_package, i) ||
rapl_defaults->check_unit(new_package, i)) {
@@ -1448,6 +1448,8 @@ static int rapl_add_package(int cpu)
/* add the new package to the list */
rp->id = phy_package_id;
rp->nr_cpus = 1;
+ rp->lead_cpu = cpu;
+
/* check if the package contains valid domains */
if (rapl_detect_domains(rp, cpu) ||
rapl_defaults->check_unit(rp, cpu)) {
@@ -1480,6 +1482,7 @@ static int rapl_cpu_callback(struct notifier_block *nfb,
unsigned long cpu = (unsigned long)hcpu;
int phy_package_id;
struct rapl_package *rp;
+ int lead_cpu;
phy_package_id = topology_physical_package_id(cpu);
switch (action) {
@@ -1500,6 +1503,15 @@ static int rapl_cpu_callback(struct notifier_block *nfb,
break;
if (--rp->nr_cpus == 0)
rapl_remove_package(rp);
+ else if (cpu == rp->lead_cpu) {
+ /* choose another active cpu in the package */
+ lead_cpu = cpumask_any_but(topology_core_cpumask(cpu), cpu);
+ if (lead_cpu < nr_cpu_ids)
+ rp->lead_cpu = lead_cpu;
+ else /* should never go here */
+ pr_err("no active cpu available for package %d\n",
+ phy_package_id);
+ }
}
return NOTIFY_OK;
--
1.9.1