On Tue, 26 May 2026 23:07:39 +0530
Praveen Talari <[email protected]> wrote:
> +DECLARE_EVENT_CLASS(geni_serial_data,
> + TP_PROTO(struct device *dev, const u8 *buf, unsigned int
> len),
> + TP_ARGS(dev, buf, len),
> +
> + TP_STRUCT__entry(__string(name, dev_name(dev))
> + __field(unsigned int, len)
> + __dynamic_array(u8, data, len)
> + ),
> +
> + TP_fast_assign(__assign_str(name);
> + __entry->len = len;
> + memcpy(__get_dynamic_array(data), buf, len);
> + ),
> +
> + TP_printk("%s: len=%u data=%s",
> + __get_str(name), __entry->len,
> + __print_hex(__get_dynamic_array(data),
> __entry->len))
> +);
No need to save the length of the dynamic array in __entry->len because
it's already saved in the metadata of the dynamic array that is stored
on the buffer. Instead you can have:
DECLARE_EVENT_CLASS(geni_serial_data,
TP_PROTO(struct device *dev, const u8 *buf, unsigned int
len),
TP_ARGS(dev, buf, len),
TP_STRUCT__entry(__string(name, dev_name(dev))
__dynamic_array(u8, data, len)
),
TP_fast_assign(__assign_str(name);
memcpy(__get_dynamic_array(data), buf, len);
),
TP_printk("%s: len=%u data=%s",
__get_str(name), __entry->len,
__print_hex(__get_dynamic_array(data),
__get_dynamic_array_len(data)))
);
That will save you 4 bytes per event on the ring buffer. And a few
cycles not having to store the redundant information.
-- Steve
