Re: [PATCH v0 14/71] perf tools: Add cpu to struct thread

[Adrian Hunter]

On 11/12/13 16:19, Arnaldo Carvalho de Melo wrote:
> Em Wed, Dec 11, 2013 at 02:36:26PM +0200, Alexander Shishkin escreveu:
>> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>>
>> Tools may wish to track on which cpu a thread
>> is running.  Add 'cpu' to struct thread for
>> that purpose.  Also add machine functions to
>> get / set the cpu for a tid.
>>
>> This will be used to determine the cpu when
>> decoding a per-thread Instruction Trace.
>>
>>
>> +++ b/tools/perf/util/machine.c
>> @@ -1412,3 +1412,29 @@ pid_t machine__get_thread_pid(struct machine *machine, pid_t tid)
>>  
>>  	return thread->pid_;
>>  }
>> +
>> +int machine__get_thread_cpu(struct machine *machine, pid_t tid, pid_t *pid)
>> +{
>> +	struct thread *thread = machine__find_thread(machine, tid);
>> +
>> +	if (!thread)
>> +		return -1;
>> +
>> +	if (pid)
>> +		*pid = thread->pid_;
>> +
>> +	return thread->cpu;
>> +}
> 
> What is the problem with:
> 
> 	struct thread *thread = machine__find_thread(machine, tid);
> 	pid_t pid = thread->pid_;
> 	int cpu = thread->cpu;
> 
> In your case you'll have:
> 
> 	int pid;
> 	int cpu = machine__get_thread_cpu(machine, tid, &pid);
> 
> Which is slightly more compact, but then we end up with a function that
> from its name should just get a 'cpu' but also asks for the pid.
> 
> I think it is better to just use what we have (machine__find_thread),
> have a 'thread' variable and then use any of its members, directly.

OK



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