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SubjectRe: [PATCH 21/57] perf c2c report: Add offset dimension key
On Wed, Oct 05, 2016 at 07:57:07AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Sep 22, 2016 at 05:36:49PM +0200, Jiri Olsa escreveu:
> > Adding cacheline offset dimension key support.
> > It displays cacheline offset as hex number.
> >
> > Link: http://lkml.kernel.org/n/tip-m0424ye98lqveg5nopto8qww@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > tools/perf/builtin-c2c.c | 35 +++++++++++++++++++++++++++++++++++
> > 1 file changed, 35 insertions(+)
> >
> > diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> > index 335c0fd30757..7c52481ec36b 100644
> > --- a/tools/perf/builtin-c2c.c
> > +++ b/tools/perf/builtin-c2c.c
> > @@ -300,6 +300,32 @@ static int dcacheline_entry(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
> > return snprintf(hpp->buf, hpp->size, "%*s", width, hex_str(addr));
> > }
> >
> > +static int offset_entry(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
> > + struct hist_entry *he)
> > +{
> > + uint64_t addr = 0;
> > + int width = c2c_width(fmt, hpp, he->hists);
> > +
> > + if (he->mem_info)
> > + addr = cl_offset(he->mem_info->daddr.al_addr);
> > +
> > + return snprintf(hpp->buf, hpp->size, "%*s", width, hex_str(addr));
>
> Please don't use snprintf when you actually use the return from this
> function, see this part of its man page:
>
> "If the output was trun‐ cated due to this limit, then the return value
> is the number of characters (excluding the terminating null byte) which
> would have been written to the final string if enough space had been
> available. Thus, a return value of size or more means that the output
> was truncated. (See also below under NOTES.)"
>
> That is why we're using scnprintf where we need to use its return value.
>
> I'm checking how you use the return value and changing all to scnprintf
> instead, ok?

ok, always forget this one ;-)

thanks,
jirka

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