[tip:tracing/ftrace] tracing: tracepoints for softirq entry/exit - tracepoints

Jason Baron
2009-03-13T04:04:06Z

Commit-ID: 39842323ceb368d2ea36ab7696aedbe296e13b61
Gitweb: http://git.kernel.org/tip/39842323ceb368d2ea36ab7696aedbe296e13b61
Author: Jason Baron <jbaron@redhat.com>
AuthorDate: Thu, 12 Mar 2009 14:36:03 -0400
Commit: Steven Rostedt <srostedt@redhat.com>
CommitDate: Thu, 12 Mar 2009 21:20:58 -0400

tracing: tracepoints for softirq entry/exit - tracepoints

Introduce softirq entry/exit tracepoints. These are useful for
augmenting existing tracers, and to figure out softirq frequencies and
timings.

[
s/irq_softirq_/softirq_/ for trace point names and
Fixed printf format in TRACE_FORMAT macro
- Steven Rostedt
]

LKML-Reference: <20090312183603.GC3352@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>

---
include/trace/irq_event_types.h | 12 ++++++++++++
kernel/softirq.c | 7 ++++++-
2 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/include/trace/irq_event_types.h b/include/trace/irq_event_types.h
index 214bb92..85964eb 100644
--- a/include/trace/irq_event_types.h
+++ b/include/trace/irq_event_types.h
@@ -40,4 +40,16 @@ TRACE_EVENT(irq_handler_exit,
__entry->irq, __entry->ret ? "handled" : "unhandled")
);

+TRACE_FORMAT(softirq_entry,
+ TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
+ TP_ARGS(h, vec),
+ TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])
+ );
+
+TRACE_FORMAT(softirq_exit,
+ TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
+ TP_ARGS(h, vec),
+ TP_FMT("softirq=%d action=%s", (int)(h - vec), softirq_to_name[h-vec])
+ );
+
#undef TRACE_SYSTEM
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 9f90fdc..a5e8123 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -24,6 +24,7 @@
#include <linux/ftrace.h>
#include <linux/smp.h>
#include <linux/tick.h>
+#include <trace/irq.h>

#include <asm/irq.h>
/*
@@ -186,6 +187,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
*/
#define MAX_SOFTIRQ_RESTART 10

+DEFINE_TRACE(softirq_entry);
+DEFINE_TRACE(softirq_exit);
+
asmlinkage void __do_softirq(void)
{
struct softirq_action *h;
@@ -212,8 +216,9 @@ restart:
if (pending & 1) {
int prev_count = preempt_count();

+ trace_softirq_entry(h, softirq_vec);
h->action(h);
-
+ trace_softirq_exit(h, softirq_vec);
if (unlikely(prev_count != preempt_count())) {
printk(KERN_ERR "huh, entered softirq %td %s %p"
"with preempt_count %08x,"