[dpdk-dev] [EXT] Re: [PATCH 3/3] l3fwd-power: add interrupt-only mode

[Burakov, Anatoly]

On 30-May-20 11:02 AM, Harman Kalra wrote:
> On Fri, May 29, 2020 at 03:19:45PM +0100, Burakov, Anatoly wrote:
>> External Email
>>
>> ----------------------------------------------------------------------
>> On 29-May-20 2:19 PM, Harman Kalra wrote:
>>
>>>>    	if (ret < 0)
>>>>    		rte_exit(EXIT_FAILURE, "Invalid L3FWD parameters\n");
>>>> -	if (app_mode != APP_MODE_TELEMETRY && init_power_library())
>>>> +	if (app_mode == APP_MODE_DEFAULT)
>>>> +		app_mode = APP_MODE_LEGACY;
>>>> +
>>>> +	/* only legacy and empty poll mode rely on power library */
>>>> +	if ((app_mode == APP_MODE_LEGACY || app_mode == APP_MODE_EMPTY_POLL) &&
>>>> +			init_power_library())
>>>>    		rte_exit(EXIT_FAILURE, "init_power_library failed\n");
>>> Hi,
>>>
>>> Rather than just exiting from here can we have a else condition to
>>> automatically enter into the "interrupt only" mode.
>>> Please correct me if I am missing something.
>>
>> Hi,
>>
>> Thanks for your review. I don't think silently proceeding is a good idea. If
>> the user wants interrupt-only mode, they should request it. Silently falling
>> back to interrupt-only mode will create an illusion of successful
>> initialization and set the wrong expectation for how the application will
>> behave.
>>
> 
> Hi,
> 
> Thanks for the explanation which even I also believe is logically perfect.
> 
> But since l3fwd-power is an old application and has many users around
> which are currently using this app in interrupt only mode without giving
> an extra argument. But suddenly they will start getting failure messages with
> the new patchset.
> 
> My only intent with else condition was backward compatibility.
> Or may be we can have more descriptive failure message, something like
> "init_power_library failed, check manual for other modes".
> 
> Thanks
> Harman
> 
> 

I think we can compormise on an informative log message suggesting to 
use interrupt mode. I'm not keen on reverting to previous buggy behavior :)

>> -- 
>> Thanks,
>> Anatoly


-- 
Thanks,
Anatoly