[PATCH 3/3] AMD Family10h+ IBS support for oProfile driver: buffer management

From: Barry Kasindorf
Date: Mon Jun 09 2008 - 14:16:51 EST

Signed-off-by: Barry Kasindorf <barry.kasindorf@xxxxxxx>

---
drivers/oprofile/buffer_sync.c | 140 ++++++++++++++++++++++++++++++-----------
drivers/oprofile/cpu_buffer.c | 102 +++++++++++++++++++++++++++--
drivers/oprofile/cpu_buffer.h | 3
include/linux/oprofile.h | 13 +++
4 files changed, 213 insertions(+), 45 deletions(-)
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index 9304c45..d6f3305 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -5,6 +5,7 @@
* @remark Read the file COPYING
*
* @author John Levon <levon@xxxxxxxxxxxxxxxxx>
+ * @author Barry Kasindorf
*
* This is the core of the buffer management. Each
* CPU buffer is processed and entered into the
@@ -33,7 +34,7 @@
#include "event_buffer.h"
#include "cpu_buffer.h"
#include "buffer_sync.h"
-
+
static LIST_HEAD(dying_tasks);
static LIST_HEAD(dead_tasks);
static cpumask_t marked_cpus = CPU_MASK_NONE;
@@ -99,7 +100,7 @@ static int munmap_notify(struct notifier_block * self, unsigned long val, void *
return 0;
}

-
+
/* We need to be told about new modules so we don't attribute to a previously
* loaded module, or drop the samples on the floor.
*/
@@ -118,7 +119,7 @@ static int module_load_notify(struct notifier_block * self, unsigned long val, v
return 0;
}

-
+
static struct notifier_block task_free_nb = {
.notifier_call = task_free_notify,
};
@@ -135,7 +136,7 @@ static struct notifier_block module_load_nb = {
.notifier_call = module_load_notify,
};

-
+
static void end_sync(void)
{
end_cpu_work();
@@ -212,10 +213,10 @@ static unsigned long get_exec_dcookie(struct mm_struct * mm)
{
unsigned long cookie = NO_COOKIE;
struct vm_area_struct * vma;
-
+
if (!mm)
goto out;
-
+
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!vma->vm_file)
continue;
@@ -241,7 +242,7 @@ static unsigned long lookup_dcookie(struct mm_struct * mm, unsigned long addr, o
struct vm_area_struct * vma;

for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
-
+
if (addr < vma->vm_start || addr >= vma->vm_end)
continue;

@@ -263,9 +264,19 @@ static unsigned long lookup_dcookie(struct mm_struct * mm, unsigned long addr, o
return cookie;
}

+static void increment_tail(struct oprofile_cpu_buffer *b)
+{
+ unsigned long new_tail = b->tail_pos + 1;
+
+ rmb(); /* be sure fifo pointers are synchromized */

+ if (new_tail < b->buffer_size)
+ b->tail_pos = new_tail;
+ else
+ b->tail_pos = 0;
+}
static unsigned long last_cookie = INVALID_COOKIE;
-
+
static void add_cpu_switch(int i)
{
add_event_entry(ESCAPE_CODE);
@@ -278,16 +289,16 @@ static void add_kernel_ctx_switch(unsigned int in_kernel)
{
add_event_entry(ESCAPE_CODE);
if (in_kernel)
- add_event_entry(KERNEL_ENTER_SWITCH_CODE);
+ add_event_entry(KERNEL_ENTER_SWITCH_CODE);
else
- add_event_entry(KERNEL_EXIT_SWITCH_CODE);
+ add_event_entry(KERNEL_EXIT_SWITCH_CODE);
}
-
+
static void
add_user_ctx_switch(struct task_struct const * task, unsigned long cookie)
{
add_event_entry(ESCAPE_CODE);
- add_event_entry(CTX_SWITCH_CODE);
+ add_event_entry(CTX_SWITCH_CODE);
add_event_entry(task->pid);
add_event_entry(cookie);
/* Another code for daemon back-compat */
@@ -296,7 +307,7 @@ add_user_ctx_switch(struct task_struct const * task, unsigned long cookie)
add_event_entry(task->tgid);
}

-
+
static void add_cookie_switch(unsigned long cookie)
{
add_event_entry(ESCAPE_CODE);
@@ -304,13 +315,74 @@ static void add_cookie_switch(unsigned long cookie)
add_event_entry(cookie);
}

-
+
static void add_trace_begin(void)
{
add_event_entry(ESCAPE_CODE);
add_event_entry(TRACE_BEGIN_CODE);
}

+/*
+ * Add IBS fetch and op entries to event buffer
+ */
+static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code,
+ int in_kernel, struct mm_struct *mm)
+{
+ unsigned long rip;
+ int i, count;
+ unsigned long ibs_cookie = 0;
+ off_t offset;
+
+ increment_tail(cpu_buf); /* move to RIP entry */
+
+ rip = ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->eip;
+
+#ifdef __LP64__
+ rip +=
+ ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->event << 32;
+#endif
+
+ if (mm) {
+ ibs_cookie = lookup_dcookie(mm, rip, &offset);
+
+ if (ibs_cookie == NO_COOKIE)
+ offset = rip;
+ if (ibs_cookie == INVALID_COOKIE) {
+ atomic_inc(&oprofile_stats.sample_lost_no_mapping);
+ offset = rip;
+ }
+ if (ibs_cookie != last_cookie) {
+ add_cookie_switch(ibs_cookie);
+ last_cookie = ibs_cookie;
+ }
+ }
+
+ else
+ offset = rip;
+
+ add_event_entry(ESCAPE_CODE);
+ add_event_entry(code);
+ add_event_entry(offset); /* Offset from Dcookie */
+
+ /* we send the Dcookie offset, but send the raw Linear Add also*/
+ add_event_entry(
+ ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->eip);
+ add_event_entry(
+ ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->event);
+
+ if (code == IBS_FETCH_CODE)
+ count = 2;
+ else
+ count = 5; /*IBS OP is 5 int64s long */
+
+ for (i = 0; i < count; i++) {
+ increment_tail(cpu_buf);
+ add_event_entry(
+ ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->eip);
+ add_event_entry(
+ ((struct op_sample *)&cpu_buf->buffer[cpu_buf->tail_pos])->event);
+ }
+}

static void add_sample_entry(unsigned long offset, unsigned long event)
{
@@ -323,9 +395,9 @@ static int add_us_sample(struct mm_struct * mm, struct op_sample * s)
{
unsigned long cookie;
off_t offset;
-
+
cookie = lookup_dcookie(mm, s->eip, &offset);
-
+
if (cookie == INVALID_COOKIE) {
atomic_inc(&oprofile_stats.sample_lost_no_mapping);
return 0;
@@ -341,7 +413,7 @@ static int add_us_sample(struct mm_struct * mm, struct op_sample * s)
return 1;
}

-
+
/* Add a sample to the global event buffer. If possible the
* sample is converted into a persistent dentry/offset pair
* for later lookup from userspace.
@@ -359,7 +431,7 @@ add_sample(struct mm_struct * mm, struct op_sample * s, int in_kernel)
}
return 0;
}
-
+

static void release_mm(struct mm_struct * mm)
{
@@ -383,7 +455,7 @@ static inline int is_code(unsigned long val)
{
return val == ESCAPE_CODE;
}
-
+

/* "acquire" as many cpu buffer slots as we can */
static unsigned long get_slots(struct oprofile_cpu_buffer * b)
@@ -412,19 +484,6 @@ static unsigned long get_slots(struct oprofile_cpu_buffer * b)
}


-static void increment_tail(struct oprofile_cpu_buffer * b)
-{
- unsigned long new_tail = b->tail_pos + 1;
-
- rmb();
-
- if (new_tail < b->buffer_size)
- b->tail_pos = new_tail;
- else
- b->tail_pos = 0;
-}
-
-
/* Move tasks along towards death. Any tasks on dead_tasks
* will definitely have no remaining references in any
* CPU buffers at this point, because we use two lists,
@@ -496,21 +555,20 @@ void sync_buffer(int cpu)
struct task_struct * new;
unsigned long cookie = 0;
int in_kernel = 1;
- unsigned int i;
sync_buffer_state state = sb_buffer_start;
unsigned long available;

mutex_lock(&buffer_mutex);
-
+
add_cpu_switch(cpu);

/* Remember, only we can modify tail_pos */

available = get_slots(cpu_buf);

- for (i = 0; i < available; ++i) {
- struct op_sample * s = &cpu_buf->buffer[cpu_buf->tail_pos];
-
+ while (get_slots(cpu_buf)) {
+ struct op_sample *s = &cpu_buf->buffer[cpu_buf->tail_pos];
+
if (is_code(s->eip)) {
if (s->event <= CPU_IS_KERNEL) {
/* kernel/userspace switch */
@@ -521,6 +579,14 @@ void sync_buffer(int cpu)
} else if (s->event == CPU_TRACE_BEGIN) {
state = sb_bt_start;
add_trace_begin();
+ } else if (s->event == IBS_FETCH_BEGIN) {
+ state = sb_bt_start;
+ add_ibs_begin(cpu_buf,
+ IBS_FETCH_CODE, in_kernel, mm);
+ } else if (s->event == IBS_OP_BEGIN) {
+ state = sb_bt_start;
+ add_ibs_begin(cpu_buf,
+ IBS_OP_CODE, in_kernel, mm);
} else {
struct mm_struct * oldmm = mm;

diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 2450b3a..b08b11d 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -5,6 +5,7 @@
* @remark Read the file COPYING
*
* @author John Levon <levon@xxxxxxxxxxxxxxxxx>
+ * @author Barry Kasindorf <barry.kasindorf@xxxxxxx>
*
* Each CPU has a local buffer that stores PC value/event
* pairs. We also log context switches when we notice them.
@@ -21,7 +22,7 @@
#include <linux/oprofile.h>
#include <linux/vmalloc.h>
#include <linux/errno.h>
-
+
#include "event_buffer.h"
#include "cpu_buffer.h"
#include "buffer_sync.h"
@@ -37,7 +38,7 @@ static int work_enabled;
void free_cpu_buffers(void)
{
int i;
-
+
for_each_online_cpu(i)
vfree(per_cpu(cpu_buffer, i).buffer);
}
@@ -45,17 +46,17 @@ void free_cpu_buffers(void)
int alloc_cpu_buffers(void)
{
int i;
-
+
unsigned long buffer_size = fs_cpu_buffer_size;
-
+
for_each_online_cpu(i) {
struct oprofile_cpu_buffer *b = &per_cpu(cpu_buffer, i);
-
+
b->buffer = vmalloc_node(sizeof(struct op_sample) * buffer_size,
cpu_to_node(i));
if (!b->buffer)
goto fail;
-
+
b->last_task = NULL;
b->last_is_kernel = -1;
b->tracing = 0;
@@ -202,12 +203,55 @@ static int log_sample(struct oprofile_cpu_buffer * cpu_buf, unsigned long pc,
cpu_buf->last_task = task;
add_code(cpu_buf, (unsigned long)task);
}
-
+
add_sample(cpu_buf, pc, event);
return 1;
}

-static int oprofile_begin_trace(struct oprofile_cpu_buffer * cpu_buf)
+static int log_ibs_sample(struct oprofile_cpu_buffer *cpu_buf,
+ unsigned long pc, int is_kernel, unsigned int *ibs, int ibs_code)
+{
+ struct task_struct *task;
+
+ cpu_buf->sample_received++;
+
+ if (nr_available_slots(cpu_buf) < 14) {
+ cpu_buf->sample_lost_overflow++;
+ return 0;
+ }
+
+ is_kernel = !!is_kernel;
+
+ /* notice a switch from user->kernel or vice versa */
+ if (cpu_buf->last_is_kernel != is_kernel) {
+ cpu_buf->last_is_kernel = is_kernel;
+ add_code(cpu_buf, is_kernel);
+ }
+
+ /* notice a task switch */
+ if (!is_kernel) {
+ task = current;
+
+ if (cpu_buf->last_task != task) {
+ cpu_buf->last_task = task;
+ add_code(cpu_buf, (unsigned long)task);
+ }
+ }
+
+ add_code(cpu_buf, ibs_code);
+ add_sample(cpu_buf, ibs[0], ibs[1]);
+ add_sample(cpu_buf, ibs[2], ibs[3]);
+ add_sample(cpu_buf, ibs[4], ibs[5]);
+
+ if (ibs_code == IBS_OP_BEGIN) {
+ add_sample(cpu_buf, ibs[6], ibs[7]);
+ add_sample(cpu_buf, ibs[8], ibs[9]);
+ add_sample(cpu_buf, ibs[10], ibs[11]);
+ }
+
+ return 1;
+}
+static int oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
{
if (nr_available_slots(cpu_buf) < 4) {
cpu_buf->sample_lost_overflow++;
@@ -252,6 +296,48 @@ void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
oprofile_add_ext_sample(pc, regs, event, is_kernel);
}

+void oprofile_add_ibs_fetch_sample(struct pt_regs *const regs,
+ unsigned int * const ibs_fetch)
+{
+ int is_kernel = !user_mode(regs);
+ unsigned long pc = profile_pc(regs);
+
+ struct oprofile_cpu_buffer *cpu_buf =
+ &per_cpu(cpu_buffer, smp_processor_id());
+
+ if (!backtrace_depth) {
+ log_ibs_sample(cpu_buf, pc, is_kernel,
+ ibs_fetch, IBS_FETCH_BEGIN);
+ return;
+ }
+
+ /* if log_sample() fails we can't backtrace since we lost the source
+ * of this event */
+ if (log_ibs_sample(cpu_buf, pc, is_kernel, ibs_fetch, IBS_FETCH_BEGIN))
+ oprofile_ops.backtrace(regs, backtrace_depth);
+}
+
+
+void oprofile_add_ibs_op_sample(struct pt_regs *const regs,
+ unsigned int * const ibs_op)
+{
+ int is_kernel = !user_mode(regs);
+ unsigned long pc = profile_pc(regs);
+
+ struct oprofile_cpu_buffer *cpu_buf =
+ &per_cpu(cpu_buffer, smp_processor_id());
+
+ if (!backtrace_depth) {
+ log_ibs_sample(cpu_buf, pc, is_kernel, ibs_op, IBS_OP_BEGIN);
+ return;
+ }
+
+ /* if log_sample() fails we can't backtrace since we lost the source
+ * of this event */
+ if (log_ibs_sample(cpu_buf, pc, is_kernel, ibs_op, IBS_OP_BEGIN))
+ oprofile_ops.backtrace(regs, backtrace_depth);
+}
+
void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
{
struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer);
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index c3e366b..4fa475f 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -53,7 +53,10 @@ DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
void cpu_buffer_reset(struct oprofile_cpu_buffer * cpu_buf);

/* transient events for the CPU buffer -> event buffer */
+#define CPU_IS_USER 0
#define CPU_IS_KERNEL 1
#define CPU_TRACE_BEGIN 2
+#define IBS_FETCH_BEGIN 3
+#define IBS_OP_BEGIN 4

#endif /* OPROFILE_CPU_BUFFER_H */
diff --git a/include/linux/oprofile.h b/include/linux/oprofile.h
index 041bb31..6fe46f7 100644
--- a/include/linux/oprofile.h
+++ b/include/linux/oprofile.h
@@ -36,6 +36,9 @@
#define XEN_ENTER_SWITCH_CODE 10
#define SPU_PROFILING_CODE 11
#define SPU_CTX_SWITCH_CODE 12
+#define IBS_FETCH_CODE 13
+#define IBS_OP_CODE 14
+

struct super_block;
struct dentry;
@@ -106,6 +109,16 @@ void oprofile_add_sample(struct pt_regs * const regs, unsigned long event);
void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
unsigned long event, int is_kernel);

+/**
+ * Add an AMD IBS sample. This may be called from any context. Pass
+ * smp_processor_id() as cpu. PAsses IBS registers as a unsigned int[8]
+ */
+void oprofile_add_ibs_op_sample(struct pt_regs * const regs,
+ unsigned int * const ibs_op);
+
+void oprofile_add_ibs_fetch_sample(struct pt_regs * const regs,
+ unsigned int * const ibs_fetch);
+
/* Use this instead when the PC value is not from the regs. Doesn't
* backtrace. */
void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event);

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