[dpdk-dev] [PATCH 07/10] eal: add core list input format

[Roger Keith Wiles]

Burn, it is not like we are going to add a huge number of new options in the future and run out of letters.

> On Nov 24, 2014, at 8:52 AM, Venkatesan, Venky <venky.venkatesan at intel.com> wrote:
> 
> 
> On 11/24/2014 5:28 AM, Bruce Richardson wrote:
>> On Mon, Nov 24, 2014 at 02:19:16PM +0100, Thomas Monjalon wrote:
>>> Hi Bruce and Neil,
>>> 
>>> 2014-11-24 11:28, Bruce Richardson:
>>>> On Sat, Nov 22, 2014 at 08:35:17PM -0500, Neil Horman wrote:
>>>>> On Sat, Nov 22, 2014 at 10:43:39PM +0100, Thomas Monjalon wrote:
>>>>>> From: Didier Pallard <didier.pallard at 6wind.com>
>>>>>> 
>>>>>> In current version, used cores can only be specified using a bitmask.
>>>>>> It will now be possible to specify cores in 2 different ways:
>>>>>> - Using a bitmask (-c [0x]nnn): bitmask must be in hex format
>>>>>> - Using a list in following format: -l <c1>[-c2][,c3[-c4],...]
>>>>>> 
>>>>>> The letter -l can stand for lcore or list.
>>>>>> 
>>>>>> -l 0-7,16-23,31 being equivalent to -c 0x80FF00FF
>>>>> Do you want to burn an option letter on that?  It seems like it might be better
>>>>> to search the string for 0x and base the selection of bitmap of list parsing
>>>>> based on its presence or absence.
>>> It was the initial proposal (in April):
>>> 	http://dpdk.org/ml/archives/dev/2014-April/002173.html
>>> And I liked keeping only 1 option;
>>> 	http://dpdk.org/ml/archives/dev/2014-May/002722.html
>>> But Anatoly raised the compatibility problem:
>>> 	http://dpdk.org/ml/archives/dev/2014-May/002723.html
>>> Then there was no other comment so Didier and I reworked a separate option.
>>> 
>>>> The existing coremask parsing always assumes a hex coremask, so just looking
>>>> for a 0x will not work. I prefer this scheme of using a new flag for this method
>>>> of specifying the cores to use.
>>>> 
>>>> If you don't want to use up a single-letter option, two alternatives:
>>>> 1) use a long option instead.
>>>> 2) if the -c parameter includes a "-" or a ",", treat it as a new-style option,
>>>> otherwise treat as old. The only abiguity here would be for specifying a single
>>>> core value 1-9 e.g. is "-c 6" a mask with two bits, or a single-core to run on.
>>>> [0 is obviously a named core as it's an invalid mask, and A-F are obviously
>>>> masks.] If we did want this scheme, I would suggest that we allow trailing
>>>> commas in the list specifier, so we can force users to clear ambiguity by
>>>> either writing "0x6" or "6," i.e. disallow ambiguous values to avoid problems.
>>>> However, this is probably more work that it's worth to avoid using up a letter
>>>> option.
>>>> 
>>>> I'd prefer any of these options to breaking backward compatibility in this case.
>>> We need a consensus here.
>>> Who is supporting a "burn" of an one-letter option with clear usage?
>>> Who is supporting a "re-merge" of the 2 syntaxes with more complicated rules
>>> (list syntax is triggered by presence of "-" or ",")?
>>> 
>> Burn!
> Burn ^ 2 ;)