RE: [PATCH RFC 10/10] dpaa_eth: add trace points

From: Madalin-Cristian Bucur
Date: Fri Apr 03 2015 - 13:30:00 EST


> -----Original Message-----
> From: Joe Perches [mailto:joe@xxxxxxxxxxx]
>
> On Wed, 2015-04-01 at 19:19 +0300, Madalin Bucur wrote:
> > Add trace points on the hot processing path.
>
> more trivia:
>
> > diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth_trace.h
> b/drivers/net/ethernet/freescale/dpaa/dpaa_eth_trace.h
> []
> > +#define fd_format_name(format) { qm_fd_##format, #format }
> > +#define fd_format_list \
> > + fd_format_name(contig), \
> > + fd_format_name(sg)
>
> Are these used anywhere?

Yes, by the Frame Descriptor print:

/* This is what gets printed when the trace event is triggered */
TP_printk(TR_FMT,
__get_str(name), __entry->fqid, __entry->fd_addr,
__print_symbolic(__entry->fd_format, fd_format_list), // <-- here
__entry->fd_offset, __entry->fd_length, __entry->fd_status)


> > +#define TR_FMT "[%s] fqid=%d, fd: addr=0x%llx, format=%s, off=%u,
> len=%u," \
> > + " status=0x%08x"
>
> It's nicer to coalesce string fragments.
>
> Unless this is intended to be used more than once,
> perhaps it's better to remove it and use the string
> directly instead.
>
> > + /* This is what gets printed when the trace event is triggered */
> > + TP_printk(TR_FMT,
> > + __get_str(name), __entry->fqid, __entry->fd_addr,
> > + __print_symbolic(__entry->fd_format, fd_format_list),
> > + __entry->fd_offset, __entry->fd_length, __entry-
> >fd_status)
>

Checkpatch seems to be less forgiving if the long string is not in a printk:

WARNING: line over 80 characters
#22: FILE: drivers/net/ethernet/freescale/dpaa/dpaa_eth_trace.h:47:
+#define TR_FMT "[%s] fqid=%d, fd: addr=0x%llx, format=%s, off=%u, len=%u, status=0x%08x"

Madalin
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