Re: [RFC PATCH v3 0/5] tracing: common error_log for ftrace

[Masami Hiramatsu]

Hi Tom,

On Tue, 5 Mar 2019 23:06:46 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> On Mon,  4 Mar 2019 17:36:43 -0600

> > Changes from v2:
> > 
> >   - Added [n] numbering as suggested by Masami
> 

Hmm, this seems a bit different what I suggested.

I'm trying to port probe event's error report on
your error log, and I found that the number is
just shifted as below.

When I filled the log with errors.
=============
/sys/kernel/debug/tracing # cat error_log 
[1] trace_kprobe: error: Invalid unsigned integer string
  Command: r10aa00:foo/bar vfs
            ^
...

[7] trace_kprobe: error: Group name must follow C naming convention
  Command: p:a-b/bar vfs_read
             ^
[8] trace_kprobe: error: Event name is too long
  Command: p:a/barrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr vfs_read
=============

And do one more error, 

=============
/sys/kernel/debug/tracing # cat error_log 
[1] trace_kprobe: error: Maxactive is too big
  Command: r0xaa00:foo/bar vfs

....

[7] trace_kprobe: error: Event name is too long
  Command: p:a/barrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr vfs_read
               ^
[8] trace_kprobe: error: Event name must follow C naming convention
  Command: p:a/bar.c vfs_read
               ^
=============

The number of logs are changed :(  This can confuse users.
I think it is better to keep the number as a unique number for
each entry as below.

=============
/sys/kernel/debug/tracing # cat error_log 
[2] trace_kprobe: error: Maxactive is too big
  Command: r0xaa00:foo/bar vfs

....

[8] trace_kprobe: error: Event name is too long
  Command: p:a/barrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr vfs_read
               ^
[9] trace_kprobe: error: Event name must follow C naming convention
  Command: p:a/bar.c vfs_read
               ^
=============

Thank you,

-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>