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Date: Thu, 3 Sep 2009 16:26:03 -0400
From: Jason Baron <jbaron@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: mathieu.desnoyers@...ymtl.ca, roland@...hat.com, rth@...hat.com,
mingo@...e.hu
Subject: [PATCH 4/4] RFC: performance testing harness
Not intended to be merged just a harness for micro-testing tracepoint performance.
Signed-off-by: Jason Baron <jbaron@...hat.com>
---
include/linux/tracepoint.h | 12 ++++
kernel/tracepoint.c | 125 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 137 insertions(+), 0 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index fdd2d8b..da657bf 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -27,6 +27,8 @@ struct tracepoint {
void (*regfunc)(void);
void (*unregfunc)(void);
void **funcs;
+ unsigned long cycle_total;
+ unsigned long count;
} __attribute__((aligned(32))); /*
* Aligned on 32 bytes because it is
* globally visible and gcc happily
@@ -69,12 +71,22 @@ struct tracepoint {
extern const char __sjstrtab_##name[]; \
static inline void trace_##name(proto) \
{ \
+ unsigned long profile_flags; \
+ u64 t1, t2; \
+ local_irq_save(profile_flags); \
+ preempt_disable(); \
+ t1 = get_cycles(); \
JUMP_LABEL_IF(name, trace_label, __tracepoint_##name.state); \
if (0) { \
trace_label: \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(proto), TP_ARGS(args)); \
} \
+ t2 = get_cycles(); \
+ local_irq_restore(profile_flags); \
+ preempt_enable(); \
+ __tracepoint_##name.count += 1; \
+ __tracepoint_##name.cycle_total += (t2 - t1); \
} \
static inline int register_trace_##name(void (*probe)(proto)) \
{ \
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 1b4acc0..4be3991 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -26,6 +26,9 @@
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/jump_label.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
extern struct tracepoint __start___tracepoints[];
extern struct tracepoint __stop___tracepoints[];
@@ -563,6 +566,78 @@ void tracepoint_iter_reset(struct tracepoint_iter *iter)
}
EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
+static void *tracepoint_seq_next(struct seq_file *seqf, void *v, loff_t *pos)
+{
+ struct tracepoint_iter *iter;
+ iter = seqf->private;
+
+ tracepoint_iter_next(iter);
+ if (iter->tracepoint) {
+ (*pos)++;
+ return iter->tracepoint;
+ }
+
+ return NULL;
+}
+
+static void tracepoint_seq_stop(struct seq_file *seqf, void *v)
+{
+ struct tracepoint_iter *iter = seqf->private;
+
+ /* stop is called even after start failed :-( */
+ if (iter)
+ kfree(iter);
+
+}
+
+static void *tracepoint_seq_start(struct seq_file *seqf, loff_t *pos)
+{
+ struct tracepoint_iter *iter;
+ loff_t skip = *pos;
+
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return ERR_PTR(-ENOMEM);
+ seqf->private = iter;
+
+ tracepoint_iter_reset(iter);
+ tracepoint_iter_start(iter);
+ do {
+ tracepoint_iter_next(iter);
+ if (!iter->tracepoint)
+ return NULL;
+ } while (skip--);
+
+ return iter->tracepoint;
+}
+
+static int show_tracepoint(struct seq_file *seqf, void *v)
+{
+ struct tracepoint *tp = v;
+
+ seq_printf(seqf, "%s %lu %lu %lu\n", tp->name, tp->cycle_total, tp->count, tp->count ? tp->cycle_total / tp->count : 0 );
+ return 0;
+}
+
+static struct seq_operations tracepoints_seq_ops = {
+ .start = tracepoint_seq_start,
+ .next = tracepoint_seq_next,
+ .stop = tracepoint_seq_stop,
+ .show = show_tracepoint
+};
+
+static int tracepoints_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &tracepoints_seq_ops);
+}
+
+static struct file_operations debugfs_tracepoint_operations = {
+ .open = tracepoints_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
#ifdef CONFIG_MODULES
int tracepoint_module_notify(struct notifier_block *self,
@@ -585,8 +660,57 @@ struct notifier_block tracepoint_module_nb = {
.priority = 0,
};
+static ssize_t write_enabled_file_bool(struct file *file,
+ const char __user *user_buf, size_t count, loff_t *ppos)
+{
+ struct tracepoint_iter *iter;
+
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return ERR_PTR(-ENOMEM);
+
+ tracepoint_iter_reset(iter);
+ tracepoint_iter_start(iter);
+ do {
+ tracepoint_iter_next(iter);
+ if (!iter->tracepoint)
+ break;
+ iter->tracepoint->count = 0;
+ iter->tracepoint->cycle_total = 0;
+ } while (1);
+
+ kfree(iter);
+ return count;
+}
+
+static struct file_operations fops_kp = {
+ .write = write_enabled_file_bool,
+};
+
+
+
static int init_tracepoints(void)
{
+ struct dentry *dir, *file;
+
+ dir = debugfs_create_dir("tracepoints", NULL);
+ if (!dir)
+ return -ENOMEM;
+
+ file = debugfs_create_file("list", 0444, dir, NULL,
+ &debugfs_tracepoint_operations);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
+
+ file = debugfs_create_file("clear", 0600, dir,
+ NULL, &fops_kp);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
+
return register_module_notifier(&tracepoint_module_nb);
}
__initcall(init_tracepoints);
@@ -630,3 +754,4 @@ void syscall_unregfunc(void)
}
}
#endif
+
--
1.6.2.5
--
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