Re: [PATCH] perf stat: Do not show stats if workload fails

[Ingo Molnar <mingo@kernel.org>]

* David Ahern <dsahern@gmail.com> wrote:

> Currently perf-stat attempts to show counter stats even if the workload
> is bogus:
> 
> $ perf stat -- foo
> foo: No such file or directory
> 
>  Performance counter stats for 'foo':
> 
>      <not counted>      task-clock
>      <not counted>      context-switches
>      <not counted>      cpu-migrations
>      <not counted>      page-faults
>      <not counted>      cycles
>      <not counted>      stalled-cycles-frontend
>      <not counted>      stalled-cycles-backend
>      <not counted>      instructions
>      <not counted>      branches
>      <not counted>      branch-misses
> 
>        0.009769943 seconds time elapsed
> 
> It is impossible to differentiate all the failure modes, but it seems
> reasonable that if the workload handling fails, perf-stat should not try
> to print stats.
> 
> With this change:
> 
> $ perf stat  -v -- foo
> Failed to start workload
> 
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Stephane Eranian <eranian@google.com>

Nice!

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo