[dpdk-dev] [PATCH v3 3/4] compressdev: replace mbuf scatter gather flag

[Verma, Shally]

>-----Original Message-----
>From: De Lara Guarch, Pablo [mailto:pablo.de.lara.guarch at intel.com]
>Sent: 05 July 2018 16:56
>To: Verma, Shally <Shally.Verma at cavium.com>; Gupta, Ashish <Ashish.Gupta at cavium.com>; Trahe, Fiona <fiona.trahe at intel.com>;
>Daly, Lee <lee.daly at intel.com>; Sahu, Sunila <Sunila.Sahu at cavium.com>
>Cc: dev at dpdk.org
>Subject: RE: [PATCH v3 3/4] compressdev: replace mbuf scatter gather flag
>
>External Email
>
>> -----Original Message-----
>> From: Verma, Shally [mailto:Shally.Verma at cavium.com]
>> Sent: Thursday, July 5, 2018 12:13 PM
>> To: De Lara Guarch, Pablo <pablo.de.lara.guarch at intel.com>; Gupta, Ashish
>> <Ashish.Gupta at cavium.com>; Trahe, Fiona <fiona.trahe at intel.com>; Daly, Lee
>> <lee.daly at intel.com>; Sahu, Sunila <Sunila.Sahu at cavium.com>
>> Cc: dev at dpdk.org
>> Subject: RE: [PATCH v3 3/4] compressdev: replace mbuf scatter gather flag
>>
>>
>>
>> >-----Original Message-----
>> >From: De Lara Guarch, Pablo [mailto:pablo.de.lara.guarch at intel.com]
>> >Sent: 05 July 2018 16:36
>> >To: Verma, Shally <Shally.Verma at cavium.com>; Gupta, Ashish
>> ><Ashish.Gupta at cavium.com>; Trahe, Fiona <fiona.trahe at intel.com>; Daly,
>> >Lee <lee.daly at intel.com>; Sahu, Sunila <Sunila.Sahu at cavium.com>
>> >Cc: dev at dpdk.org
>> >Subject: RE: [PATCH v3 3/4] compressdev: replace mbuf scatter gather
>> >flag
>> >
>> >External Email
>> >
>> >> -----Original Message-----
>> >> From: Verma, Shally [mailto:Shally.Verma at cavium.com]
>> >> Sent: Thursday, July 5, 2018 9:39 AM
>> >> To: De Lara Guarch, Pablo <pablo.de.lara.guarch at intel.com>; Gupta,
>> >> Ashish <Ashish.Gupta at cavium.com>; Trahe, Fiona
>> >> <fiona.trahe at intel.com>; Daly, Lee <lee.daly at intel.com>; Sahu, Sunila
>> >> <Sunila.Sahu at cavium.com>
>> >> Cc: dev at dpdk.org
>> >> Subject: RE: [PATCH v3 3/4] compressdev: replace mbuf scatter gather
>> >> flag
>> >>
>> >>
>> >>
>> >> >-----Original Message-----
>> >> >From: Pablo de Lara [mailto:pablo.de.lara.guarch at intel.com]
>> >> >Sent: 04 July 2018 19:41
>> >> >To: Verma, Shally <Shally.Verma at cavium.com>; Gupta, Ashish
>> >> ><Ashish.Gupta at cavium.com>; fiona.trahe at intel.com; lee.daly at intel.com
>> >> >Cc: dev at dpdk.org; Pablo de Lara <pablo.de.lara.guarch at intel.com>
>> >> >Subject: [PATCH v3 3/4] compressdev: replace mbuf scatter gather
>> >> >flag
>> >> >
>> >> >External Email
>> >> >
>> >> >The current mbuf scatter gather feature flag is too ambiguous, as it
>> >> >is not clear if input and/or output buffers can be scatter gather
>> >> >mbufs or not.
>> >> >
>> >> >Therefore, three new flags will replace this flag:
>> >> >- RTE_COMP_FF_OOP_SGL_IN_SGL_OUT
>> >> >- RTE_COMP_FF_OOP_SGL_IN_FB_OUT
>> >> >- RTE_COMP_FF_OOP_FB_IN_SGL_OUT
>> >> >
>> >> [Shally] Believe Out of place is default support on current
>> >> compression API, so why do we need _OOP_ here?
>> >
>> >Hi Shally,
>> >
>> >You are right, but I just wanted to clarify that the scenario is for Out of place
>> only.
>> >
>> Ok. But that looks redundant to me. Though not likely, tomorrow if some algo
>> support in-place, Then we will end up adding in_place equivalent of same. So
>> would prefer to keep naming generic of in/out place and specific to Scatter-
>> gather in/out support.
>
>I think I am not quite following you. Actually, if in the future we support
>In-place, then it is important to have OOP in the macro, to specify that SGL
>is supported for Out-of-place and maybe not in-place (like in cryptodev).
>Otherwise, we would need to break the API, which can be avoided now.

Ohh okay, now I get it. So these feature flags intend to show input/output mode supported
specifically for in/out of place operations.  But then still I see having OOP isn't required as compression
default support is out-of-place and it's just making feature name too big. Having in-place is exception 
and if supported, can use convention RTE_COMP_FF_INPLACE_xx

Above one comment, as I see it, use of FB in RTE_COMP_FF_OOP_FB_IN_SGL_OUT didn't give clear indication what it mean.
May be replace it by RTE_COMP_FF_OOP_DIRECT/LINEAR_IN_SGL_OUT

Just few suggestions.
Thanks
Shally

- 



>
>Thanks,
>Pablo
>
>>
>> >Thanks,
>> >Pablo
>> >
>> >>
>> >> Thanks
>> >> Shally
>> >> >Note that out-of-place flat buffers is supported by default and
>> >> >in-place is not supported by the library.
>> >> >
>> >> >Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
>> >> >Acked-by: Fiona Trahe <fiona.trahe at intel.com>