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Date: Wed, 24 Feb 2016 13:31:36 -0800
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: LKML <linux-kernel@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
Rafael Wysocki <rafael.j.wysocki@...el.com>,
Thomas Gleixner <tglx@...utronix.de>
Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Andrew Morton <akpm@...ux-foundation.org>,
"David S. Miller" <davem@...emloft.net>,
Rusty Russell <rusty@...tcorp.com.au>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH v6 2/4] powercap/rapl: reduce ipi calls
Reduce remote CPU calls for MSR access by combining read
modify write into one function.
Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
---
drivers/powercap/intel_rapl.c | 119 ++++++++++++++++++++++++++++++------------
1 file changed, 85 insertions(+), 34 deletions(-)
diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index 6c592dc..a50e644 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)
@@ -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;
- }
- l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
- wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+ 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_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)
--
1.9.1
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