Re: [dpdk-dev] [PATCH] compressdev: add feature flag to specify where processing is done

["Verma, Shally" <Shally.Verma@cavium.com>]

HI Pablo

Sorry for delay in response.

>-----Original Message-----
>From: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>
>Sent: 11 January 2019 00:17
>To: Trahe, Fiona <fiona.trahe@intel.com>; Verma, Shally <Shally.Verma@cavium.com>; Stephen Hemminger
><stephen@networkplumber.org>
>Cc: dev@dpdk.org; akhil.goyal@nxp.com; Jozwiak, TomaszX <tomaszx.jozwiak@intel.com>; Gupta, Ashish
><Ashish.Gupta@cavium.com>; Daly, Lee <lee.daly@intel.com>; Luse, Paul E <paul.e.luse@intel.com>; Trahe, Fiona
><fiona.trahe@intel.com>
>Subject: RE: [dpdk-dev] [PATCH] compressdev: add feature flag to specify where processing is done
>
....

>> > >> I just did a survey of DPDK an 1/3 of it is never used by any open
>> > >> source project.  Hate to see more dead code and special cases created.
>> > >>
>> > >> At least, some example code in examples would help. Something like
>> > >> a simple in memory compressed storage server using a network API
>> > >> (SMB?/SSH?/FTP?)
>> > >[Fiona] There is no compressdev sample app yet.
>> > >However I've double-checked with the SPDK team, they're currently
>> > >integrating compressdev and intend to push a patch to SPDK - a storage
>> open-source project - using this flag.
>> > [Shally] Am seeing some of our HW based PMD also leveraging this
>> > choice. So I would say to make it generic feature flag instead of SW specific.
>>  [Fiona] I can do but would like to understand this better first.
>> My understanding of HW offload is that the enqueue is just packaging up
>> the op and sending to the HW.
>> And the dequeue is just collecting the result from the HW and passing back
>> to the op.
>> The work is done by the HW accelerator, in between those 2 API calls, not
>> using any CPU cycles.
>> So what would it mean for HW to set OP_DONE_IN_DEQUEUE?
>
>Any comments on this? I agree with Fiona that this flag makes sense on SW only,
>but it seems that you have another use case.
I am waiting for feedback on this internally. Will revert on this as I get more information.

Thanks
Shally
>
>Thanks,
>Pablo
>
>>
>> > Thanks
>> > Shally