Re: [PATCH] perf tool: Fix output unexpected messages in quiet mode

[Yang Jihong]

Hello,

On 2022/12/19 14:59, Adrian Hunter wrote:
> On 19/12/22 04:49, Yang Jihong wrote:
> > When perf uses quiet mode, perf_quiet_option sets debug_peo_args to -1,
>
> Seems like redirect_to_stderr has similar issue?
The redirect_to_stderr is used only in the veprintf function:

  int veprintf(int level, int var, const char *fmt, va_list args)
  {
          int ret = 0;

          if (var >= level) {
                  if (use_browser >= 1 && redirect_to_stderr <= 0) {
                          ui_helpline__vshow(fmt, args);
                  } else {
                          ret = fprintf_time(debug_file);
                          ret += vfprintf(debug_file, fmt, args);
                  }
          }

          return ret;
  }

If use quiet mode, verbose sets to -1. (also assigned in the 
perf_quiet_option function)
Because "var >= level" is false, veprintf function returns directly, 
which avoids this problem.

However, there are cases where:
  # perf --debug stderr=-1 report -vvv 2>/tmp/debug

If stderr is -1, should we redirect pr_debug in this case?

Because I'm not sure if this is a problem,
if redirect_to_stderr needs to be fixed as well,
let me know and I'll submit a patch to fix it.

> > and display_attr incorrectly determines the value of debug_peo_args.
> > As a result, unexpected information is displayed.
> >
> > Before:
> >    # perf record --quiet -- ls > /dev/null
> >    ------------------------------------------------------------
> >    perf_event_attr:
> >      size                             128
> >      { sample_period, sample_freq }   4000
> >      sample_type                      IP|TID|TIME|PERIOD
> >      read_format                      ID|LOST
> >      disabled                         1
> >      inherit                          1
> >      mmap                             1
> >      comm                             1
> >      freq                             1
> >      enable_on_exec                   1
> >      task                             1
> >      precise_ip                       3
> >      sample_id_all                    1
> >      exclude_guest                    1
> >      mmap2                            1
> >      comm_exec                        1
> >      ksymbol                          1
> >      bpf_event                        1
> >    ------------------------------------------------------------
> >    ...
> >
> > After:
> >    # perf record --quiet -- ls > /dev/null
> >    #
> >
> > Fixes: ccd26741f5e6 ("perf tool: Provide an option to print perf_event_open args and return value")
> > Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
>
> Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Thanks for reviewed-by.

Thanks,
Yang