Em Sun, Jun 18, 2017 at 11:22:59PM +0900, Namhyung Kim escreveu:
> It'd be better for debugging to show an error message when it fails to
> setup ftrace for some reason.
Thanks a lot, tested the series, excellent ftrace subset to support in
'perf ftrace'! :-)
- Arnaldo
> Cc: Steven Rostedt <rost...@goodmis.org>
> Cc: Frederic Weisbecker <fweis...@gmail.com>
> Signed-off-by: Namhyung Kim <namhy...@kernel.org>
> ---
> tools/perf/builtin-ftrace.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index 9e0b35cd0eea..966a94fa8200 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -61,6 +61,7 @@ static int __write_tracing_file(const char *name, const
> char *val, bool append)
> int fd, ret = -1;
> ssize_t size = strlen(val);
> int flags = O_WRONLY;
> + char errbuf[512];
>
> file = get_tracing_file(name);
> if (!file) {
> @@ -75,14 +76,16 @@ static int __write_tracing_file(const char *name, const
> char *val, bool append)
>
> fd = open(file, flags);
> if (fd < 0) {
> - pr_debug("cannot open tracing file: %s\n", name);
> + pr_debug("cannot open tracing file: %s: %s\n",
> + name, str_error_r(errno, errbuf, sizeof(errbuf)));
> goto out;
> }
>
> if (write(fd, val, size) == size)
> ret = 0;
> else
> - pr_debug("write '%s' to tracing/%s failed\n", val, name);
> + pr_debug("write '%s' to tracing/%s failed: %s\n",
> + val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
>
> close(fd);
> out:
> --
> 2.13.0
