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Oprofile Multiplexing Patch

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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>
This commit is contained in:
Jason Yeh 2008-07-23 23:05:53 +02:00 committed by Ingo Molnar
parent 6852fd9b86
commit 1a960b402a
10 changed files with 247 additions and 45 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

100
arch/x86/oprofile/nmi_int.c
View file

@ -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 @@ static void exit_sysfs(void)
#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 void free_msrs(void)
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 @@ static int allocate_msrs(void)
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 @@ static int nmi_setup(void)
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 @@ static int nmi_setup(void)
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 @@ static int nmi_setup(void)
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 @@ static void nmi_cpu_shutdown(void *dummy)
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 @@ static int nmi_create_files(struct super_block *sb, struct dentry *root)
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 @@ int __init op_nmi_init(struct oprofile_operations *ops)
}
/* 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);

3
arch/x86/oprofile/op_counter.h
View file

@ -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;

76
arch/x86/oprofile/op_model_amd.c
View file

@ -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 @@ static void op_amd_fill_in_addresses(struct op_msrs * const msrs)
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 @@ static void op_amd_setup_ctrs(struct op_msrs const * const msrs)
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 @@ static void op_amd_setup_ctrs(struct op_msrs const * const msrs)
}
/* 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 @@ static int op_amd_check_ctrs(struct pt_regs * const regs,
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 @@ static void op_amd_start(struct op_msrs const * const msrs)
{
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 @@ static void op_amd_stop(struct op_msrs const * const msrs)
/* 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 @@ static void op_amd_shutdown(struct op_msrs const * const msrs)
{
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 @@ struct op_x86_model_spec const op_amd_spec = {
.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,

4
arch/x86/oprofile/op_model_p4.c
View file

@ -701,6 +701,8 @@ static void p4_shutdown(struct op_msrs const * const msrs)
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_ht2_spec = {
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,

2
arch/x86/oprofile/op_model_ppro.c
View file

@ -183,6 +183,8 @@ static void ppro_shutdown(struct op_msrs const * const msrs)
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,

3
arch/x86/oprofile/op_x86_model.h
View file

@ -19,6 +19,7 @@ struct op_saved_msr {
struct op_msr {
unsigned long addr;
struct op_saved_msr saved;
struct op_saved_msr multiplex;
};
struct op_msrs {
@ -34,6 +35,8 @@ struct pt_regs;
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);

58
drivers/oprofile/oprof.c
View file

@ -12,6 +12,8 @@
#include <linux/init.h>
#include <linux/oprofile.h>
#include <linux/moduleparam.h>
#include <linux/workqueue.h>
#include <linux/time.h>
#include <asm/mutex.h>
#include "oprof.h"
@ -19,13 +21,18 @@
#include "cpu_buffer.h"
#include "buffer_sync.h"
#include "oprofile_stats.h"
static unsigned long is_setup;
static void switch_worker(struct work_struct *work);
static DECLARE_DELAYED_WORK(switch_work, switch_worker);
static DEFINE_MUTEX(start_mutex);
struct oprofile_operations oprofile_ops;
unsigned long timeout_jiffies;
unsigned long oprofile_started;
unsigned long backtrace_depth;
static unsigned long is_setup;
static DEFINE_MUTEX(start_mutex);
/* Multiplexing defaults at 1 msec*/
/* timer
0 - use performance monitoring hardware if available
@ -87,6 +94,16 @@ int oprofile_setup(void)
return err;
}
static void start_switch_worker(void)
{
schedule_delayed_work(&switch_work, timeout_jiffies);
}
static void switch_worker(struct work_struct *work)
{
if (!oprofile_ops.switch_events())
start_switch_worker();
}
/* Actually start profiling (echo 1>/dev/oprofile/enable) */
int oprofile_start(void)
@ -94,7 +111,6 @@ int oprofile_start(void)
int err = -EINVAL;
mutex_lock(&start_mutex);
if (!is_setup)
goto out;
@ -108,6 +124,9 @@ int oprofile_start(void)
if ((err = oprofile_ops.start()))
goto out;
if (oprofile_ops.switch_events)
start_switch_worker();
oprofile_started = 1;
out:
mutex_unlock(&start_mutex);
@ -123,6 +142,7 @@ void oprofile_stop(void)
goto out;
oprofile_ops.stop();
oprofile_started = 0;
cancel_delayed_work_sync(&switch_work);
/* wake up the daemon to read what remains */
wake_up_buffer_waiter();
out:
@ -155,6 +175,32 @@ void oprofile_shutdown(void)
mutex_unlock(&start_mutex);
}
/* User inputs in ms, converts to jiffies */
int oprofile_set_timeout(unsigned long val_msec)
{
int err = 0;
mutex_lock(&start_mutex);
if (oprofile_started) {
err = -EBUSY;
goto out;
}
if (!oprofile_ops.switch_events) {
err = -EINVAL;
goto out;
}
timeout_jiffies = msecs_to_jiffies(val_msec);
if (timeout_jiffies == MAX_JIFFY_OFFSET)
timeout_jiffies = msecs_to_jiffies(1);
out:
mutex_unlock(&start_mutex);
return err;
}
int oprofile_set_backtrace(unsigned long val)
{
@ -179,10 +225,16 @@ int oprofile_set_backtrace(unsigned long val)
return err;
}
static void __init oprofile_switch_timer_init(void)
{
timeout_jiffies = msecs_to_jiffies(1);
}
static int __init oprofile_init(void)
{
int err;
oprofile_switch_timer_init();
err = oprofile_arch_init(&oprofile_ops);
if (err < 0 || timer) {

4
drivers/oprofile/oprof.h
View file

@ -27,7 +27,8 @@ extern unsigned long fs_buffer_watershed;
extern struct oprofile_operations oprofile_ops;
extern unsigned long oprofile_started;
extern unsigned long backtrace_depth;
extern unsigned long timeout_jiffies;
struct super_block;
struct dentry;
@ -35,5 +36,6 @@ void oprofile_create_files(struct super_block * sb, struct dentry * root);
void oprofile_timer_init(struct oprofile_operations * ops);
int oprofile_set_backtrace(unsigned long depth);
int oprofile_set_timeout(unsigned long time);
#endif /* OPROF_H */

39
drivers/oprofile/oprofile_files.c
View file

@ -9,6 +9,7 @@
#include <linux/fs.h>
#include <linux/oprofile.h>
#include <linux/jiffies.h>
#include "event_buffer.h"
#include "oprofile_stats.h"
@ -18,6 +19,40 @@ unsigned long fs_buffer_size = 131072;
unsigned long fs_cpu_buffer_size = 8192;
unsigned long fs_buffer_watershed = 32768; /* FIXME: tune */
static ssize_t timeout_read(struct file *file, char __user *buf,
size_t count, loff_t *offset)
{
return oprofilefs_ulong_to_user(jiffies_to_msecs(timeout_jiffies),
buf, count, offset);
}
static ssize_t timeout_write(struct file *file, char const __user *buf,
size_t count, loff_t *offset)
{
unsigned long val;
int retval;
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
return retval;
retval = oprofile_set_timeout(val);
if (retval)
return retval;
return count;
}
static const struct file_operations timeout_fops = {
.read = timeout_read,
.write = timeout_write,
};
static ssize_t depth_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
{
return oprofilefs_ulong_to_user(backtrace_depth, buf, count, offset);
@ -85,11 +120,10 @@ static ssize_t enable_write(struct file * file, char const __user * buf, size_t
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
if (retval)
return retval;
if (val)
retval = oprofile_start();
else
@ -129,6 +163,7 @@ void oprofile_create_files(struct super_block * sb, struct dentry * root)
oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
oprofilefs_create_file(sb, root, "timeout_ms", &timeout_fops);
oprofile_create_stats_files(sb, root);
if (oprofile_ops.create_files)
oprofile_ops.create_files(sb, root);

3
include/linux/oprofile.h
View file

@ -67,6 +67,9 @@ struct oprofile_operations {
/* Initiate a stack backtrace. Optional. */
void (*backtrace)(struct pt_regs * const regs, unsigned int depth);
/* Multiplex between different events. Optional. */
int (*switch_events)(void);
/* CPU identification string. */
char * cpu_type;
};