On Fri, Dec 17, 2021 at 6:11 AM Paul Chaignon <paul@xxxxxxxxxxxxx> wrote:
>
> The output of bpftool prog tracelog is currently buffered, which is
> inconvenient when piping the output into other commands. A simple
> tracelog | grep will typically not display anything. This patch fixes it
> by flushing the tracelog output after each line from the trace_pipe file.
>
> Fixes: 30da46b5dc3a ("tools: bpftool: add a command to dump the trace pipe")
> Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
> Signed-off-by: Paul Chaignon <paul@xxxxxxxxxxxxx>
> ---
> Changes in v2:
> - Resending to fix a format error.
>
> tools/bpf/bpftool/tracelog.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tools/bpf/bpftool/tracelog.c b/tools/bpf/bpftool/tracelog.c
> index e80a5c79b38f..b310229abb07 100644
> --- a/tools/bpf/bpftool/tracelog.c
> +++ b/tools/bpf/bpftool/tracelog.c
> @@ -158,6 +158,7 @@ int do_tracelog(int argc, char **argv)
> jsonw_string(json_wtr, buff);
> else
> printf("%s", buff);
> + fflush(stdout);
maybe it's better to
setlinebuf(stdout);
for the entire bpftool instead?
> }
>
> fclose(trace_pipe_fd);
> --
> 2.25.1
>
