Hi Shally, > -----Original Message----- > From: dev [mailto:[email protected]] On Behalf Of Trahe, Fiona > Sent: Wednesday, December 19, 2018 5:10 PM > To: Verma, Shally <[email protected]>; Stephen Hemminger > <[email protected]> > Cc: [email protected]; [email protected]; Jozwiak, TomaszX > <[email protected]>; Gupta, Ashish <[email protected]>; > Daly, Lee <[email protected]>; Luse, Paul E <[email protected]>; Trahe, > Fiona <[email protected]> > Subject: Re: [dpdk-dev] [PATCH] compressdev: add feature flag to specify > where processing is done > > Hi Shally, > > > -----Original Message----- > > From: Verma, Shally [mailto:[email protected]] > > Sent: Tuesday, December 18, 2018 10:48 PM > > To: Trahe, Fiona <[email protected]>; Stephen Hemminger > > <[email protected]> > > Cc: [email protected]; [email protected]; Jozwiak, TomaszX > > <[email protected]>; Gupta, Ashish > <[email protected]>; > > Daly, Lee <[email protected]>; Luse, Paul E <[email protected]> > > Subject: RE: [dpdk-dev] [PATCH] compressdev: add feature flag to > > specify where processing is done > > > > > > > > >-----Original Message----- > > >From: Trahe, Fiona <[email protected]> > > >Sent: 18 December 2018 20:13 > > >To: Stephen Hemminger <[email protected]> > > >Cc: [email protected]; [email protected]; Jozwiak, TomaszX > > ><[email protected]>; Verma, > > Shally > > ><[email protected]>; Gupta, Ashish > <[email protected]>; > > >Daly, Lee > > <[email protected]>; Luse, Paul E > > ><[email protected]>; Trahe, Fiona <[email protected]> > > >Subject: RE: [dpdk-dev] [PATCH] compressdev: add feature flag to > > >specify where processing is done > > > > > >External Email > > > > > >Hi Stephen > > > > > >//snip// > > >> > > Subject: Re: [dpdk-dev] [PATCH] compressdev: add feature flag > > >> > > to specify where processing is > > done > > >> > > > > >> > > On Tue, 20 Nov 2018 01:39:48 +0000 Fiona Trahe > > >> > > <[email protected]> wrote: > > >> > > > > >> > > > A new device feature flag, > > >> > > > RTE_COMPDEV_FF_SW_OP_DONE_IN_DEQUEUE > > >> > > > is added. A PMD which processes operations using a software > > >> > > > acceleration engine should set this if the bulk of the > > >> > > > processing is done during the dequeue. It should leave it > > >> > > > cleared if the bulk of the processing is done during the > > >> > > > enqueue (default). > > >> > > > An application may find this useful for tuning. > > >> > > > > > >> > > > Signed-off-by: Fiona Trahe <[email protected]> > > >> > > > > >> > > What application? or is this "if we build it they will come?" > > >> > [Fiona] Our storage team asked for this, so not quite. > > >> > Seems like it might by generically useful, so a bit of the latter > > >> > too :) Would you prefer I removed that line? > > >> > > >> Hopefully, there would be one or more open source projects using the > API. > > >> 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. Thanks, Pablo > > > Thanks > > Shally
