2014-11-18 23:16:08

by Tom Huynh

Subject: [PATCH] perf hist browser: change print format from lu to llu to fit u64 type

nr_events in tools/perf/ui/browsers/hists.c is of type u64, thus it should
be printed as %llu instead of %lu. The print format %lu causes perf report
to show 0 event count when running with 32-bit userspace without
redirection. This patch fixes that problem.

Signed-off-by: Tom Huynh <[email protected]>
---
tools/perf/ui/browsers/hists.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index cfb976b..49b2471 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -1254,7 +1254,7 @@ static int hists__browser_title(struct hists *hists,

nr_samples = convert_unit(nr_samples, &unit);
printed = scnprintf(bf, size,
- "Samples: %lu%c of event '%s', Event count (approx.): %lu",
+ "Samples: %lu%c of event '%s', Event count (approx.): %llu",
nr_samples, unit, ev_name, nr_events);


--
1.9.1

2014-11-25 23:51:32

by Matt Mullins

Subject: Re: [PATCH] perf hist browser: change print format from lu to llu to fit u64 type

On Tue, Nov 18, 2014 at 05:00:27PM -0600, Tom Huynh wrote:
> nr_events in tools/perf/ui/browsers/hists.c is of type u64, thus it should
> be printed as %llu instead of %lu. The print format %lu causes perf report
> to show 0 event count when running with 32-bit userspace without
> redirection. This patch fixes that problem.
>
> Signed-off-by: Tom Huynh <[email protected]>
> ---
> tools/perf/ui/browsers/hists.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index cfb976b..49b2471 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -1254,7 +1254,7 @@ static int hists__browser_title(struct hists *hists,
>
> nr_samples = convert_unit(nr_samples, &unit);
> printed = scnprintf(bf, size,
> - "Samples: %lu%c of event '%s', Event count (approx.): %lu",
> + "Samples: %lu%c of event '%s', Event count (approx.): %llu",
> nr_samples, unit, ev_name, nr_events);

If I enable __attribute__((format(printf, ...))) on scnprintf, on a 64-bit
build this gives me:

ui/browsers/hists.c: In function ‘hists__browser_title’:
ui/browsers/hists.c:1258:7: error: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 7 has type ‘u64’ [-Werror=format=]
nr_samples, unit, ev_name, nr_events);
^

I would usually suggest using the PRIu64 macro which should(TM) evaluate to the
right string constant for the platform, but that appears to be a C99 thing.
I'm not sure if that's kosher in tools/perf, but it does seem to build for me
(on Fedora 20).

2014-11-26 07:57:38

by Jiri Olsa

Subject: Re: [PATCH] perf hist browser: change print format from lu to llu to fit u64 type

On Tue, Nov 25, 2014 at 03:51:30PM -0800, Matt Mullins wrote:
> On Tue, Nov 18, 2014 at 05:00:27PM -0600, Tom Huynh wrote:
> > nr_events in tools/perf/ui/browsers/hists.c is of type u64, thus it should
> > be printed as %llu instead of %lu. The print format %lu causes perf report
> > to show 0 event count when running with 32-bit userspace without
> > redirection. This patch fixes that problem.
> >
> > Signed-off-by: Tom Huynh <[email protected]>
> > ---
> > tools/perf/ui/browsers/hists.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> > index cfb976b..49b2471 100644
> > --- a/tools/perf/ui/browsers/hists.c
> > +++ b/tools/perf/ui/browsers/hists.c
> > @@ -1254,7 +1254,7 @@ static int hists__browser_title(struct hists *hists,
> >
> > nr_samples = convert_unit(nr_samples, &unit);
> > printed = scnprintf(bf, size,
> > - "Samples: %lu%c of event '%s', Event count (approx.): %lu",
> > + "Samples: %lu%c of event '%s', Event count (approx.): %llu",
> > nr_samples, unit, ev_name, nr_events);
>
> If I enable __attribute__((format(printf, ...))) on scnprintf, on a 64-bit
> build this gives me:
>
> ui/browsers/hists.c: In function ‘hists__browser_title’:
> ui/browsers/hists.c:1258:7: error: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 7 has type ‘u64’ [-Werror=format=]
> nr_samples, unit, ev_name, nr_events);
> ^
>
> I would usually suggest using the PRIu64 macro which should(TM) evaluate to the
> right string constant for the platform, but that appears to be a C99 thing.
> I'm not sure if that's kosher in tools/perf, but it does seem to build for me
> (on Fedora 20).

[jolsa@krava linux-perf]$ grep -rI PRIu64 tools/perf/ | wc -l
97

yep, it's kosher enough ;-)

jirka