Re: [PATCH v2] perf sched timehist: Improve error message when analyzing wrong file

[David Ahern]

On 11/29/16 9:31 PM, Namhyung Kim wrote:
> On 11/30/16, David Ahern <dsahern@xxxxxxxxx> wrote:
>> Arnaldo reported an unhelpful error message when running perf sched
>> timehist on a file that did not contain sched tracepoints:
>>
>>     [root@jouet ~]# perf sched timehist
>>     No trace sample to read. Did you call 'perf record -R'?
>>
>>     [root@jouet ~]# perf evlist -v
>>     cycles:ppp: size: 112, { sample_period, sample_freq }: 4000,
>> sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD, disabled: 1, inherit: 1,
>> mmap: 1, comm: 1, freq: 1, task: 1, precise_ip: 3, sample_id_all: 1,
>> exclude_guest: 1, mmap2: 1, comm_exec: 1
>>
>> Change the has_traces check to look for the sched_switch event. Analysis
>> for perf sched timehist requires at least this event.
>>
>> Now when analyzing a file without sched tracepoints you get:
>>
>>     root@f21-vbox:/tmp$ perf sched timehist
>>     No sched_switch events found. Have you run 'perf sched record'?
>>
>> Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
> 
> Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> 
> Thanks,
> Namhyung
> 

Arnaldo: I think this one has been overlooked