On Tue, 22 Nov 2016 11:01:27 +0100
Uwe Kleine-König <u...@kleine-koenig.org> wrote:

> diff --git a/include/trace/events/mdio.h b/include/trace/events/mdio.h
> new file mode 100644
> index 000000000000..468e2d095d19
> --- /dev/null
> +++ b/include/trace/events/mdio.h
> @@ -0,0 +1,42 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM mdio
> +
> +#if !defined(_TRACE_MDIO_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_MDIO_H
> +
> +#include <linux/tracepoint.h>
> +
> +TRACE_EVENT_CONDITION(mdio_access,
> +
> +     TP_PROTO(struct mii_bus *bus, int read,
> +              unsigned addr, unsigned regnum, u16 val, int err),
> +
> +     TP_ARGS(bus, read, addr, regnum, val, err),
> +
> +     TP_CONDITION(err >= 0),
> +
> +     TP_STRUCT__entry(
> +             __array(char, busid, MII_BUS_ID_SIZE)
> +             __field(int, read)

read is just a 0 or 1. What about making it a char? That way we can
pack this better. If I'm not mistaken, MII_BUS_ID_SIZE is (20 - 3) or
17. If read is just one byte, then it can fit in one of those three
bytes, and you save 4 extra bytes (assuming addr will be 4 byte
aligned).

-- Steve


> +             __field(unsigned, addr)
> +             __field(unsigned, regnum)
> +             __field(u16, val)
> +     ),
> +
> +     TP_fast_assign(
> +             strncpy(__entry->busid, bus->id, MII_BUS_ID_SIZE);
> +             __entry->read = read;
> +             __entry->addr = addr;
> +             __entry->regnum = regnum;
> +             __entry->val = val;
> +     ),
> +
> +     TP_printk("%s %-5s phy:0x%02x reg:0x%02x val:0x%04hx",
> +               __entry->busid, __entry->read ? "read" : "write",
> +               __entry->addr, __entry->regnum, __entry->val)
> +);
> +
> +#endif /* if !defined(_TRACE_MDIO_H) || defined(TRACE_HEADER_MULTI_READ) */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>

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