* [PATCH bpf v2] bpftool: Flush tracelog output
@ 2021-12-17 14:11 Paul Chaignon
2021-12-17 16:51 ` Andrii Nakryiko
0 siblings, 1 reply; 3+ messages in thread
From: Paul Chaignon @ 2021-12-17 14:11 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko; +Cc: bpf, Quentin Monnet
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@isovalent.com>
Signed-off-by: Paul Chaignon <paul@isovalent.com>
---
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);
}
fclose(trace_pipe_fd);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH bpf v2] bpftool: Flush tracelog output
2021-12-17 14:11 [PATCH bpf v2] bpftool: Flush tracelog output Paul Chaignon
@ 2021-12-17 16:51 ` Andrii Nakryiko
2021-12-20 21:48 ` Paul Chaignon
0 siblings, 1 reply; 3+ messages in thread
From: Andrii Nakryiko @ 2021-12-17 16:51 UTC (permalink / raw)
To: Paul Chaignon
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, bpf,
Quentin Monnet
On Fri, Dec 17, 2021 at 6:11 AM Paul Chaignon <paul@isovalent.com> 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@isovalent.com>
> Signed-off-by: Paul Chaignon <paul@isovalent.com>
> ---
> 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
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH bpf v2] bpftool: Flush tracelog output
2021-12-17 16:51 ` Andrii Nakryiko
@ 2021-12-20 21:48 ` Paul Chaignon
0 siblings, 0 replies; 3+ messages in thread
From: Paul Chaignon @ 2021-12-20 21:48 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, bpf,
Quentin Monnet
On Fri, Dec 17, 2021 at 08:51:01AM -0800, Andrii Nakryiko wrote:
> On Fri, Dec 17, 2021 at 6:11 AM Paul Chaignon <paul@isovalent.com> 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@isovalent.com>
> > Signed-off-by: Paul Chaignon <paul@isovalent.com>
> > ---
> > 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?
Makes sense. I've sent a v3 at
https://lore.kernel.org/bpf/20211220214528.GA11706@Mem/T/.
>
>
> > }
> >
> > fclose(trace_pipe_fd);
> > --
> > 2.25.1
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-17 14:11 [PATCH bpf v2] bpftool: Flush tracelog output Paul Chaignon
2021-12-17 16:51 ` Andrii Nakryiko
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