Re: [PATCH v4] bus: mhi: host: Add tracing support

[Krishna Chaitanya Chundru]

On 11/12/2023 1:07 AM, Steven Rostedt wrote:
> On Sat, 11 Nov 2023 11:25:22 +0530
> Krishna chaitanya chundru <quic_krichai@xxxxxxxxxxx> wrote:
> > diff --git a/drivers/bus/mhi/host/trace.h b/drivers/bus/mhi/host/trace.h
> > new file mode 100644
> > index 000000000000..0e99318f5d08
> > --- /dev/null
> > +++ b/drivers/bus/mhi/host/trace.h
> > +
> > +TRACE_EVENT(mhi_update_channel_state_start,
> > +
> > +	TP_PROTO(const char *name, int ch_num, int state),
> > +
> > +	TP_ARGS(name, ch_num, state),
> > +
> > +	TP_STRUCT__entry(
> > +		__string(name, name)
> > +		__field(int, ch_num)
> > +		__field(int, state)
> > +	),
> > +
> > +	TP_fast_assign(
> > +		__assign_str(name, name);
> > +		__entry->ch_num = ch_num;
> > +		__entry->state = state;
> > +	),
> > +
> > +	TP_printk("%s: ch%d: Updating state to: %s\n",
> > +		  __get_str(name), __entry->ch_num,
> > +		  TO_CH_STATE_TYPE_STR(__entry->state))
> > +);
> > +
> > +TRACE_EVENT(mhi_update_channel_state_end,
> > +
> > +	TP_PROTO(const char *name, int ch_num, int state),
> > +
> > +	TP_ARGS(name, ch_num, state),
> > +
> > +	TP_STRUCT__entry(
> > +		__string(name, name)
> > +		__field(int, ch_num)
> > +		__field(int, state)
> > +	),
> > +
> > +	TP_fast_assign(
> > +		__assign_str(name, name);
> > +		__entry->ch_num = ch_num;
> > +		__entry->state = state;
> > +	),
> > +
> > +	TP_printk("%s: ch%d: Updated state to: %s\n",
> > +		  __get_str(name), __entry->ch_num,
> > +		  TO_CH_STATE_TYPE_STR(__entry->state))
> > +);
> > +
> The above three events have the same format. You can save kilobytes of
> memory by converting them into a DECLARE_EVENT_CLASS() and use
> DEFINE_EVENT() for each event.
>
> A TRACE_EVENT() macro is really just a wrapper around
> DECLARE_EVENT_CLASS() and DEFINE_EVENT(). The DECLARE_EVENT_CLASS()
> does the bulk of the work and adds the most memory footprint. By
> breaking it apart for several events, it does save memory.
>
> Whenever you can use a single DECLARE_EVENT_CLASS() for multiple
> events, I strongly suggest doing so.
>
> Thanks,
>
> -- Steve

Sure steve I will change as suggested in my next patch.

- Krishna Chaitanya.

> > +#endif
> > +#undef TRACE_INCLUDE_PATH
> > +#define TRACE_INCLUDE_PATH .
> > +#undef TRACE_INCLUDE_FILE
> > +#define TRACE_INCLUDE_FILE trace
> > +
> > +#include <trace/define_trace.h>
> >
> > ---
> > base-commit: 3006adf3be79cde4d14b1800b963b82b6e5572e0
> > change-id: 20231005-ftrace_support-6869d4156139
> >
> > Best regards,