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

[Neil Horman <nhorman@tuxdriver.com>]

On Mon, Nov 24, 2014 at 10:12:33AM -0600, Roger Keith Wiles wrote:
> Burn, it is not like we are going to add a huge number of new options in the future and run out of letters.
> 
No, but what about the application authors that need to accomodate all of the
dpdk command line options as well?
Neil

> > On Nov 24, 2014, at 8:52 AM, Venkatesan, Venky <venky.venkatesan@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@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 ;)
> 
>