Hi Masami,

On Thu, 2019-02-14 at 12:13 +0900, Masami Hiramatsu wrote:

Hi Tom,

Thank you for your great work!

Thanks!

On Wed, 13 Feb 2019 12:17:51 -0600
Tom Zanussi [off-list ref] wrote:

quoted

From: Tom Zanussi <redacted>

Last April, I posted an RFC patchset [1] implementing a common
error_log interface as suggested by Masami [2].  We were supposed
to
discuss it at Plumbers but that never happened, and Steve recently
asked about patches for a follow-on discussion [3], so here they
are.

[snip]

quoted

  # cat /sys/kernel/debug/tracing/error_log
  hist:sched:sched_wakeup: error: Variable already defined
  Command: keys=pid:ts0=common_timestamp.usecs if
comm=="cyclictest"
                    ^
  hist:sched:sched_waking: error: Couldn't find onmax or onchange
variable
    Command: key=comm:p=prio:onchange($q).snapshot()
                                       ^
  hist:sched:sched_wakeup: error: Hist trigger already exists
    Command: keys=pid
             ^
  event filter parse error: error: Invalid operator
    Command: comm="cyclictest"
                  ^
  event filter parse error: error: Field not found
    Command: ((sig >= 10 && sig < 15) || dsig == 17) && comm !=
bash
                                              ^  

I like this very much! One point I would like to comment is to add a
kind of
entry number tag, so that user distinguish the error message, e.g.

  # cat /sys/kernel/debug/tracing/error_log
  [1] hist:sched:sched_wakeup: error: Variable already defined
    Command: keys=pid:ts0=common_timestamp.usecs if
comm=="cyclictest"
                    ^
  [2] hist:sched:sched_waking: error: Couldn't find onmax or onchange
variable
    Command: key=comm:p=prio:onchange($q).snapshot()
                                       ^
  [3] hist:sched:sched_wakeup: error: Hist trigger already exists
    Command: keys=pid
             ^
  ...

What would you think?

I think that makes sense and would be simple to add - will do in the
next version.

Thanks,

Tom

Thank you,