Re: [PATCH 4/4] libtracefs: Implement API to create / modify and display histograms

["Yordan Karadzhov (VMware)" <y.karadz@gmail.com>]

On 7.07.21 г. 16:13, Steven Rostedt wrote:
> On Wed, 7 Jul 2021 11:12:03 +0300
> "Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:
> 
>> Hi Steven,
> 
>>> +
>>> +	switch (cmd) {
>>> +	case START:
>>> +		ret = tracefs_hist_start(hist);
>>> +		if (ret) {
>>> +			char *err = tracefs_error_last(instance);
>>> +			if (err)
>>> +				fprintf(stderr, "\n%s\n", err);
>>> +		}
>>> +		break;
>>> +	case PAUSE:
>>> +		ret = tracefs_hist_pause(hist);
>>> +		break;
>>> +	case CONT:
>>> +		ret = tracefs_hist_continue(hist);
>>> +		break;
>>> +	case RESET:
>>> +		ret = tracefs_hist_reset(hist);
>>> +		break;
>>> +	case DELETE:
>>> +		ret = tracefs_hist_destroy(hist);
>>> +		break;
>>> +	case SHOW: {
>>> +		char *content;
>>> +		content = tracefs_event_file_read(instance, "kmem", "kmalloc",
>>> +						  "hist", NULL);
>>
>> It looks more intuitive to have
>>
>> char *tracefs_hist_read(struct tracefs_hist *hist)
> 
> I thought a little about this, and rather have parsing of the file. We
> could always add a helper function to do this later if it is helpful,
> 
>>
>>> +		ret = content ? 0 : -1;
>>> +		if (content) {
>>> +			printf("%s\n", content);
>>> +			free(content);
>>> +		}
>>> +		break;
>>> +	}
>>> +	}
>>
>> This "switch" can move to the library as well.
>> We can have a method
>>
>> int tracefs_hist_ctrl(struct tracefs_hist *hist,
>> 		      const char *cmd,
>> 		      void *output);
>>
> 
> Both this and the read file above could be added as enhancements, but I
> don't think we need to add them to this current patch.
> 

Yes, sure.

But maybe in this case you can postpone the addition of the examples for 
another patch that is after having those enhancements.

Thanks!
Yordan


> Thanks,
> 
> -- Steve
>