Oprofile Multiplexing Patch
This patch introduces multiplexing support for the Oprofile kernel
module. It basically adds a new function pointer in oprofile_operator
allowing each architecture to supply its callback to switch between
different sets of event when the timer expires. Userspace tools can
modify the time slice through /dev/oprofile/time_slice.
It also modifies the number of counters exposed to the userspace through
/dev/oprofile. For example, the number of counters for AMD CPUs are
changed to 32 and multiplexed in the sets of 4.
Signed-off-by: Jason Yeh <jason.yeh@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 287513a..2a65fe7 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -23,12 +23,18 @@
#include "op_counter.h"
#include "op_x86_model.h"
+DEFINE_PER_CPU(int, switch_index);
+
static struct op_x86_model_spec const *model;
static DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
static DEFINE_PER_CPU(unsigned long, saved_lvtpc);
static int nmi_start(void);
static void nmi_stop(void);
+static void nmi_cpu_save_mpx_registers(struct op_msrs *msrs);
+static void nmi_cpu_restore_mpx_registers(struct op_msrs *msrs);
+static void nmi_cpu_stop(void *dummy);
+static void nmi_cpu_start(void *dummy);
/* 0 == registered but off, 1 == registered and on */
static int nmi_enabled = 0;
@@ -81,6 +87,47 @@
#define exit_sysfs() do { } while (0)
#endif /* CONFIG_PM */
+static void nmi_cpu_switch(void *dummy)
+{
+ int cpu = smp_processor_id();
+ int si = per_cpu(switch_index, cpu);
+ struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
+
+ nmi_cpu_stop(NULL);
+ nmi_cpu_save_mpx_registers(msrs);
+
+ /* move to next set */
+ si += model->num_hardware_counters;
+ if ((si > model->num_counters) || (counter_config[si].count == 0))
+ per_cpu(switch_index, smp_processor_id()) = 0;
+ else
+ per_cpu(switch_index, smp_processor_id()) = si;
+
+ nmi_cpu_restore_mpx_registers(msrs);
+ model->setup_ctrs(msrs);
+ nmi_cpu_start(NULL);
+}
+
+/*
+ * Quick check to see if multiplexing is necessary.
+ * The check should be sufficient since counters are used
+ * in ordre.
+ */
+static int nmi_multiplex_on(void)
+{
+ return counter_config[model->num_hardware_counters].count ? 0 : -EINVAL;
+}
+
+static int nmi_switch_event(void)
+{
+ if (nmi_multiplex_on() < 0)
+ return -EINVAL;
+
+ on_each_cpu(nmi_cpu_switch, NULL, 0, 1);
+
+ return 0;
+}
+
static int profile_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
@@ -144,11 +191,10 @@
static int allocate_msrs(void)
{
- int success = 1;
+ int i, success = 1;
size_t controls_size = sizeof(struct op_msr) * model->num_controls;
size_t counters_size = sizeof(struct op_msr) * model->num_counters;
- int i;
for_each_possible_cpu(i) {
per_cpu(cpu_msrs, i).counters = kmalloc(counters_size,
GFP_KERNEL);
@@ -156,8 +202,8 @@
success = 0;
break;
}
- per_cpu(cpu_msrs, i).controls = kmalloc(controls_size,
- GFP_KERNEL);
+ per_cpu(cpu_msrs, i).controls =
+ kmalloc(controls_size, GFP_KERNEL);
if (!per_cpu(cpu_msrs, i).controls) {
success = 0;
break;
@@ -201,7 +247,8 @@
return err;
}
- /* We need to serialize save and setup for HT because the subset
+ /*
+ * We need to serialize save and setup for HT because the subset
* of msrs are distinct for save and setup operations
*/
@@ -217,7 +264,6 @@
per_cpu(cpu_msrs, 0).controls,
sizeof(struct op_msr) * model->num_controls);
}
-
}
on_each_cpu(nmi_save_registers, NULL, 1);
on_each_cpu(nmi_cpu_setup, NULL, 1);
@@ -225,7 +271,41 @@
return 0;
}
-static void nmi_restore_registers(struct op_msrs *msrs)
+static void nmi_cpu_save_mpx_registers(struct op_msrs *msrs)
+{
+ unsigned int si = __get_cpu_var(switch_index);
+ unsigned int const nr_ctrs = model->num_hardware_counters;
+ struct op_msr *counters = &msrs->counters[si];
+ unsigned int i;
+
+ for (i = 0; i < nr_ctrs; ++i) {
+ int offset = i + si;
+ if (counters[offset].addr) {
+ rdmsr(counters[offset].addr,
+ counters[offset].multiplex.low,
+ counters[offset].multiplex.high);
+ }
+ }
+}
+
+static void nmi_cpu_restore_mpx_registers(struct op_msrs *msrs)
+{
+ unsigned int si = __get_cpu_var(switch_index);
+ unsigned int const nr_ctrs = model->num_hardware_counters;
+ struct op_msr *counters = &msrs->counters[si];
+ unsigned int i;
+
+ for (i = 0; i < nr_ctrs; ++i) {
+ int offset = i + si;
+ if (counters[offset].addr) {
+ wrmsr(counters[offset].addr,
+ counters[offset].multiplex.low,
+ counters[offset].multiplex.high);
+ }
+ }
+}
+
+static void nmi_cpu_restore_registers(struct op_msrs *msrs)
{
unsigned int const nr_ctrs = model->num_counters;
unsigned int const nr_ctrls = model->num_controls;
@@ -265,7 +345,8 @@
apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
apic_write(APIC_LVTPC, per_cpu(saved_lvtpc, cpu));
apic_write(APIC_LVTERR, v);
- nmi_restore_registers(msrs);
+ nmi_cpu_restore_registers(msrs);
+ __get_cpu_var(switch_index) = 0;
}
static void nmi_shutdown(void)
@@ -328,6 +409,7 @@
oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
+ counter_config[i].save_count_low = 0;
}
return 0;
@@ -469,12 +551,14 @@
}
/* default values, can be overwritten by model */
+ __get_cpu_var(switch_index) = 0;
ops->create_files = nmi_create_files;
ops->setup = nmi_setup;
ops->shutdown = nmi_shutdown;
ops->start = nmi_start;
ops->stop = nmi_stop;
ops->cpu_type = cpu_type;
+ ops->switch_events = nmi_switch_event;
if (model->init)
ret = model->init(ops);
diff --git a/arch/x86/oprofile/op_counter.h b/arch/x86/oprofile/op_counter.h
index 2880b15..786d6e0 100644
--- a/arch/x86/oprofile/op_counter.h
+++ b/arch/x86/oprofile/op_counter.h
@@ -10,13 +10,14 @@
#ifndef OP_COUNTER_H
#define OP_COUNTER_H
-#define OP_MAX_COUNTER 8
+#define OP_MAX_COUNTER 32
/* Per-perfctr configuration as set via
* oprofilefs.
*/
struct op_counter_config {
unsigned long count;
+ unsigned long save_count_low;
unsigned long enabled;
unsigned long event;
unsigned long kernel;
diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index d9faf60..bbf2b68 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -15,6 +15,7 @@
#include <linux/oprofile.h>
#include <linux/device.h>
#include <linux/pci.h>
+#include <linux/percpu.h>
#include <asm/ptrace.h>
#include <asm/msr.h>
@@ -23,8 +24,10 @@
#include "op_x86_model.h"
#include "op_counter.h"
-#define NUM_COUNTERS 4
-#define NUM_CONTROLS 4
+#define NUM_COUNTERS 32
+#define NUM_HARDWARE_COUNTERS 4
+#define NUM_CONTROLS 32
+#define NUM_HARDWARE_CONTROLS 4
#define CTR_IS_RESERVED(msrs, c) (msrs->counters[(c)].addr ? 1 : 0)
#define CTR_READ(l, h, msrs, c) do {rdmsr(msrs->counters[(c)].addr, (l), (h)); } while (0)
@@ -48,6 +51,7 @@
#define CTRL_SET_GUEST_ONLY(val, h) (val |= ((h & 1) << 8))
static unsigned long reset_value[NUM_COUNTERS];
+DECLARE_PER_CPU(int, switch_index);
#ifdef CONFIG_OPROFILE_IBS
@@ -130,15 +134,17 @@
int i;
for (i = 0; i < NUM_COUNTERS; i++) {
- if (reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i))
- msrs->counters[i].addr = MSR_K7_PERFCTR0 + i;
+ int hw_counter = i % NUM_HARDWARE_COUNTERS;
+ if (reserve_perfctr_nmi(MSR_K7_PERFCTR0 + hw_counter))
+ msrs->counters[i].addr = MSR_K7_PERFCTR0 + hw_counter;
else
msrs->counters[i].addr = 0;
}
for (i = 0; i < NUM_CONTROLS; i++) {
- if (reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i))
- msrs->controls[i].addr = MSR_K7_EVNTSEL0 + i;
+ int hw_control = i % NUM_HARDWARE_CONTROLS;
+ if (reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + hw_control))
+ msrs->controls[i].addr = MSR_K7_EVNTSEL0 + hw_control;
else
msrs->controls[i].addr = 0;
}
@@ -150,8 +156,16 @@
unsigned int low, high;
int i;
+ for (i = 0; i < NUM_HARDWARE_CONTROLS; ++i) {
+ int offset = i + __get_cpu_var(switch_index);
+ if (counter_config[offset].enabled)
+ reset_value[offset] = counter_config[offset].count;
+ else
+ reset_value[offset] = 0;
+ }
+
/* clear all counters */
- for (i = 0 ; i < NUM_CONTROLS; ++i) {
+ for (i = 0 ; i < NUM_HARDWARE_CONTROLS; ++i) {
if (unlikely(!CTRL_IS_RESERVED(msrs, i)))
continue;
CTRL_READ(low, high, msrs, i);
@@ -161,34 +175,31 @@
}
/* avoid a false detection of ctr overflows in NMI handler */
- for (i = 0; i < NUM_COUNTERS; ++i) {
+ for (i = 0; i < NUM_HARDWARE_COUNTERS; ++i) {
if (unlikely(!CTR_IS_RESERVED(msrs, i)))
continue;
CTR_WRITE(1, msrs, i);
}
/* enable active counters */
- for (i = 0; i < NUM_COUNTERS; ++i) {
- if ((counter_config[i].enabled) && (CTR_IS_RESERVED(msrs, i))) {
- reset_value[i] = counter_config[i].count;
-
- CTR_WRITE(counter_config[i].count, msrs, i);
+ for (i = 0; i < NUM_HARDWARE_COUNTERS; ++i) {
+ int offset = i + __get_cpu_var(switch_index);
+ if ((counter_config[offset].enabled) && (CTR_IS_RESERVED(msrs, i))) {
+ CTR_WRITE(counter_config[offset].count, msrs, i);
CTRL_READ(low, high, msrs, i);
CTRL_CLEAR_LO(low);
CTRL_CLEAR_HI(high);
CTRL_SET_ENABLE(low);
- CTRL_SET_USR(low, counter_config[i].user);
- CTRL_SET_KERN(low, counter_config[i].kernel);
- CTRL_SET_UM(low, counter_config[i].unit_mask);
- CTRL_SET_EVENT_LOW(low, counter_config[i].event);
- CTRL_SET_EVENT_HIGH(high, counter_config[i].event);
+ CTRL_SET_USR(low, counter_config[offset].user);
+ CTRL_SET_KERN(low, counter_config[offset].kernel);
+ CTRL_SET_UM(low, counter_config[offset].unit_mask);
+ CTRL_SET_EVENT_LOW(low, counter_config[offset].event);
+ CTRL_SET_EVENT_HIGH(high, counter_config[offset].event);
CTRL_SET_HOST_ONLY(high, 0);
CTRL_SET_GUEST_ONLY(high, 0);
CTRL_WRITE(low, high, msrs, i);
- } else {
- reset_value[i] = 0;
}
}
}
@@ -276,13 +287,14 @@
unsigned int low, high;
int i;
- for (i = 0 ; i < NUM_COUNTERS; ++i) {
- if (!reset_value[i])
+ for (i = 0 ; i < NUM_HARDWARE_COUNTERS ; ++i) {
+ int offset = i + __get_cpu_var(switch_index);
+ if (!reset_value[offset])
continue;
CTR_READ(low, high, msrs, i);
if (CTR_OVERFLOWED(low)) {
- oprofile_add_sample(regs, i);
- CTR_WRITE(reset_value[i], msrs, i);
+ oprofile_add_sample(regs, offset);
+ CTR_WRITE(reset_value[offset], msrs, i);
}
}
@@ -298,8 +310,10 @@
{
unsigned int low, high;
int i;
- for (i = 0 ; i < NUM_COUNTERS ; ++i) {
- if (reset_value[i]) {
+
+ for (i = 0 ; i < NUM_HARDWARE_COUNTERS ; ++i) {
+ int offset = i + __get_cpu_var(switch_index);
+ if (reset_value[offset]) {
CTRL_READ(low, high, msrs, i);
CTRL_SET_ACTIVE(low);
CTRL_WRITE(low, high, msrs, i);
@@ -329,8 +343,8 @@
/* Subtle: stop on all counters to avoid race with
* setting our pm callback */
- for (i = 0 ; i < NUM_COUNTERS ; ++i) {
- if (!reset_value[i])
+ for (i = 0 ; i < NUM_HARDWARE_COUNTERS ; ++i) {
+ if (!reset_value[i + per_cpu(switch_index, smp_processor_id())])
continue;
CTRL_READ(low, high, msrs, i);
CTRL_SET_INACTIVE(low);
@@ -356,11 +370,11 @@
{
int i;
- for (i = 0 ; i < NUM_COUNTERS ; ++i) {
+ for (i = 0 ; i < NUM_HARDWARE_COUNTERS ; ++i) {
if (CTR_IS_RESERVED(msrs, i))
release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
}
- for (i = 0 ; i < NUM_CONTROLS ; ++i) {
+ for (i = 0 ; i < NUM_HARDWARE_COUNTERS ; ++i) {
if (CTRL_IS_RESERVED(msrs, i))
release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
}
@@ -534,6 +548,8 @@
.exit = op_amd_exit,
.num_counters = NUM_COUNTERS,
.num_controls = NUM_CONTROLS,
+ .num_hardware_counters = NUM_HARDWARE_COUNTERS,
+ .num_hardware_controls = NUM_HARDWARE_CONTROLS,
.fill_in_addresses = &op_amd_fill_in_addresses,
.setup_ctrs = &op_amd_setup_ctrs,
.check_ctrs = &op_amd_check_ctrs,
diff --git a/arch/x86/oprofile/op_model_p4.c b/arch/x86/oprofile/op_model_p4.c
index 56b4757..e641545 100644
--- a/arch/x86/oprofile/op_model_p4.c
+++ b/arch/x86/oprofile/op_model_p4.c
@@ -701,6 +701,8 @@
struct op_x86_model_spec const op_p4_ht2_spec = {
.num_counters = NUM_COUNTERS_HT2,
.num_controls = NUM_CONTROLS_HT2,
+ .num_hardware_counters = NUM_COUNTERS_HT2,
+ .num_hardware_controls = NUM_CONTROLS_HT2,
.fill_in_addresses = &p4_fill_in_addresses,
.setup_ctrs = &p4_setup_ctrs,
.check_ctrs = &p4_check_ctrs,
@@ -713,6 +715,8 @@
struct op_x86_model_spec const op_p4_spec = {
.num_counters = NUM_COUNTERS_NON_HT,
.num_controls = NUM_CONTROLS_NON_HT,
+ .num_hardware_counters = NUM_COUNTERS_NON_HT,
+ .num_hardware_controls = NUM_CONTROLS_NON_HT,
.fill_in_addresses = &p4_fill_in_addresses,
.setup_ctrs = &p4_setup_ctrs,
.check_ctrs = &p4_check_ctrs,
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index eff431f..e5811aa 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -183,6 +183,8 @@
struct op_x86_model_spec const op_ppro_spec = {
.num_counters = NUM_COUNTERS,
.num_controls = NUM_CONTROLS,
+ .num_hardware_counters = NUM_COUNTERS,
+ .num_hardware_controls = NUM_CONTROLS,
.fill_in_addresses = &ppro_fill_in_addresses,
.setup_ctrs = &ppro_setup_ctrs,
.check_ctrs = &ppro_check_ctrs,
diff --git a/arch/x86/oprofile/op_x86_model.h b/arch/x86/oprofile/op_x86_model.h
index 05a0261..e07ba10 100644
--- a/arch/x86/oprofile/op_x86_model.h
+++ b/arch/x86/oprofile/op_x86_model.h
@@ -19,6 +19,7 @@
struct op_msr {
unsigned long addr;
struct op_saved_msr saved;
+ struct op_saved_msr multiplex;
};
struct op_msrs {
@@ -34,6 +35,8 @@
struct op_x86_model_spec {
int (*init)(struct oprofile_operations *ops);
void (*exit)(void);
+ unsigned int const num_hardware_counters;
+ unsigned int const num_hardware_controls;
unsigned int const num_counters;
unsigned int const num_controls;
void (*fill_in_addresses)(struct op_msrs * const msrs);