Re: [Patch 2/2] tracepoints for softirq entry/exit - tracepoints

Steven Rostedt
2009-03-16T19:17:22Z

On Mon, 16 Mar 2009, Jason Baron wrote:

> hi,
>
> ok, below is a re-spun patch 2/2 which converts to the TRACE_EVENT
> format.

Thanks, some comments though.

>
> thanks,
>
> -Jason
>
>
> Signed-off-by: Jason Baron <jbaron@redhat.com>
>
> ---
>
> include/trace/irq_event_types.h | 36 ++++++++++++++++++++++++++++++++++++
> kernel/softirq.c | 7 ++++++-
> 2 files changed, 42 insertions(+), 1 deletions(-)
>
>
> diff --git a/include/trace/irq_event_types.h b/include/trace/irq_event_types.h
> index 214bb92..de1f2a9 100644
> --- a/include/trace/irq_event_types.h
> +++ b/include/trace/irq_event_types.h
> @@ -40,4 +40,40 @@ TRACE_EVENT(irq_handler_exit,
> __entry->irq, __entry->ret ? "handled" : "unhandled")
> );
>
> +TRACE_EVENT(softirq_action_entry,
> +
> + TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
> +
> + TP_ARGS(h, vec),
> +
> + TP_STRUCT__entry(
> + __array( char, softirq_name, MAX_SOFTIRQ_NAME_LEN )
> + ),
> +
> + TP_fast_assign(
> + memcpy(__entry->softirq_name, softirq_to_name[h-vec],
> + MAX_SOFTIRQ_NAME_LEN);

memcpy isn't fast ;-)

What you want is this:

TP_STRUCT__entry(
__field( int, vec )
),

TP_fast_assign(
__entry->vec = h - vec;
> + ),
> +
> + TP_printk("softirq entry: %s", __entry->softirq_name)

TP_printk("softirq entry: %s", softirq_to_name[__entry->vec])

> +);
> +
> +TRACE_EVENT(softirq_action_exit,
> +
> + TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
> +
> + TP_ARGS(h, vec),
> +
> + TP_STRUCT__entry(
> + __array( char, softirq_name, MAX_SOFTIRQ_NAME_LEN )
> + ),
> +
> + TP_fast_assign(
> + memcpy(__entry->softirq_name, softirq_to_name[h-vec],
> + MAX_SOFTIRQ_NAME_LEN);
> + ),
> +
> + TP_printk("softirq exit: %s", __entry->softirq_name)

And do the same here.

-- Steve

> +);
> +
> #undef TRACE_SYSTEM
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index 8f3ae57..5e96c77 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>
> /*
> @@ -185,6 +186,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
> */
> #define MAX_SOFTIRQ_RESTART 10
>
> +DEFINE_TRACE(softirq_action_entry);
> +DEFINE_TRACE(softirq_action_exit);
> +
> asmlinkage void __do_softirq(void)
> {
> struct softirq_action *h;
> @@ -211,8 +215,9 @@ restart:
> if (pending & 1) {
> int prev_count = preempt_count();
>
> + trace_softirq_action_entry(h, softirq_vec);
> h->action(h);
> -
> + trace_softirq_action_exit(h, softirq_vec);
> if (unlikely(prev_count != preempt_count())) {
> printk(KERN_ERR "huh, entered softirq %td %s %p"
> "with preempt_count %08x,"
>