Hi > -----Original Message----- > From: Trahe, Fiona [mailto:fiona.tr...@intel.com] > Sent: 26 January 2018 00:13 > To: Verma, Shally <shally.ve...@cavium.com>; Ahmed Mansour > <ahmed.mans...@nxp.com>; dev@dpdk.org; Akhil Goyal > <akhil.go...@nxp.com> > Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, Narayana > Prasad <narayanaprasad.athr...@cavium.com>; De Lara Guarch, Pablo > <pablo.de.lara.gua...@intel.com>; Gupta, Ashish > <ashish.gu...@cavium.com>; Sahu, Sunila <sunila.s...@cavium.com>; > Jain, Deepak K <deepak.k.j...@intel.com>; Hemant Agrawal > <hemant.agra...@nxp.com>; Roy Pledge <roy.ple...@nxp.com>; Youri > Querry <youri.querr...@nxp.com>; Trahe, Fiona <fiona.tr...@intel.com> > Subject: RE: [RFC v3 1/1] lib: add compressdev API > > Hi Shally, Ahmed, > > > > -----Original Message----- > > From: Verma, Shally [mailto:shally.ve...@cavium.com] > > Sent: Thursday, January 25, 2018 10:25 AM > > To: Ahmed Mansour <ahmed.mans...@nxp.com>; Trahe, Fiona > <fiona.tr...@intel.com>; > > dev@dpdk.org; Akhil Goyal <akhil.go...@nxp.com> > > Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, Narayana > Prasad > > <narayanaprasad.athr...@cavium.com>; De Lara Guarch, Pablo > <pablo.de.lara.gua...@intel.com>; > > Gupta, Ashish <ashish.gu...@cavium.com>; Sahu, Sunila > <sunila.s...@cavium.com>; Jain, Deepak K > > <deepak.k.j...@intel.com>; Hemant Agrawal > <hemant.agra...@nxp.com>; Roy Pledge > > <roy.ple...@nxp.com>; Youri Querry <youri.querr...@nxp.com> > > Subject: RE: [RFC v3 1/1] lib: add compressdev API > > > > > > > > > -----Original Message----- > > > From: Ahmed Mansour [mailto:ahmed.mans...@nxp.com] > > > Sent: 25 January 2018 01:06 > > > To: Verma, Shally <shally.ve...@cavium.com>; Trahe, Fiona > > > <fiona.tr...@intel.com>; dev@dpdk.org; Akhil Goyal > > > <akhil.go...@nxp.com> > > > Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, Narayana > > > Prasad <narayanaprasad.athr...@cavium.com>; De Lara Guarch, Pablo > > > <pablo.de.lara.gua...@intel.com>; Gupta, Ashish > > > <ashish.gu...@cavium.com>; Sahu, Sunila <sunila.s...@cavium.com>; > > > Jain, Deepak K <deepak.k.j...@intel.com>; Hemant Agrawal > > > <hemant.agra...@nxp.com>; Roy Pledge <roy.ple...@nxp.com>; Youri > > > Querry <youri.querr...@nxp.com> > > > Subject: Re: [RFC v3 1/1] lib: add compressdev API > > > > > > Hi All, > > > > > > Please see responses in line. > > > > > > Thanks, > > > > > > Ahmed > > > > > > On 1/23/2018 6:58 AM, Verma, Shally wrote: > > > > Hi Fiona > > > > > > > >> -----Original Message----- > > > >> From: Trahe, Fiona [mailto:fiona.tr...@intel.com] > > > >> Sent: 19 January 2018 17:30 > > > >> To: Verma, Shally <shally.ve...@cavium.com>; dev@dpdk.org; > > > >> akhil.go...@nxp.com > > > >> Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, Narayana > > > >> Prasad <narayanaprasad.athr...@cavium.com>; De Lara Guarch, > Pablo > > > >> <pablo.de.lara.gua...@intel.com>; Gupta, Ashish > > > >> <ashish.gu...@cavium.com>; Sahu, Sunila > <sunila.s...@cavium.com>; > > > >> Jain, Deepak K <deepak.k.j...@intel.com>; Hemant Agrawal > > > >> <hemant.agra...@nxp.com>; Roy Pledge <roy.ple...@nxp.com>; > Youri > > > >> Querry <youri.querr...@nxp.com>; Ahmed Mansour > > > >> <ahmed.mans...@nxp.com>; Trahe, Fiona <fiona.tr...@intel.com> > > > >> Subject: RE: [RFC v3 1/1] lib: add compressdev API > > > >> > > > >> Hi Shally, > > > >> > > > >>> -----Original Message----- > > > >>> From: Verma, Shally [mailto:shally.ve...@cavium.com] > > > >>> Sent: Thursday, January 18, 2018 12:54 PM > > > >>> To: Trahe, Fiona <fiona.tr...@intel.com>; dev@dpdk.org > > > >>> Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, > Narayana > > > >> Prasad > > > >>> <narayanaprasad.athr...@cavium.com>; De Lara Guarch, Pablo > > > >> <pablo.de.lara.gua...@intel.com>; > > > >>> Gupta, Ashish <ashish.gu...@cavium.com>; Sahu, Sunila > > > >> <sunila.s...@cavium.com>; Jain, Deepak K > > > >>> <deepak.k.j...@intel.com>; Hemant Agrawal > > > >> <hemant.agra...@nxp.com>; Roy Pledge > > > >>> <roy.ple...@nxp.com>; Youri Querry <youri.querr...@nxp.com>; > > > >> Ahmed Mansour > > > >>> <ahmed.mans...@nxp.com> > > > >>> Subject: RE: [RFC v3 1/1] lib: add compressdev API > > > >>> > > > >>> Hi Fiona > > > >>> > > > >>> While revisiting this, we identified few questions and additions. > Please > > > see > > > >> them inline. > > > >>> > > > >>>> -----Original Message----- > > > >>>> From: Trahe, Fiona [mailto:fiona.tr...@intel.com] > > > >>>> Sent: 15 December 2017 23:19 > > > >>>> To: dev@dpdk.org; Verma, Shally <shally.ve...@cavium.com> > > > >>>> Cc: Challa, Mahipal <mahipal.cha...@cavium.com>; Athreya, > Narayana > > > >>>> Prasad <narayanaprasad.athr...@cavium.com>; > > > >>>> pablo.de.lara.gua...@intel.com; fiona.tr...@intel.com > > > >>>> Subject: [RFC v3 1/1] lib: add compressdev API > > > >>>> > > > >>>> Signed-off-by: Trahe, Fiona <fiona.tr...@intel.com> > > > >>>> --- > > > >>> //snip > > > >>> > > > >>>> + > > > >>>> +int > > > >>>> +rte_compressdev_queue_pair_setup(uint8_t dev_id, uint16_t > > > >>>> queue_pair_id, > > > >>>> + uint32_t max_inflight_ops, int socket_id) > > > >>> [Shally] Is max_inflights_ops different from nb_streams_per_qp in > > > struct > > > >> rte_compressdev_info? > > > >>> I assume they both carry same purpose. If yes, then it will be better > to > > > use > > > >> single naming convention to > > > >>> avoid confusion. > > > >> [Fiona] No, I think they have different purposes. > > > >> max_inflight_ops should be used to configure the qp with the number > of > > > ops > > > >> the application expects to be able to submit to the qp before it needs > to > > > poll > > > >> for a response. It can be configured differently for each qp. In the > > > >> QAT > > > case it > > > >> dictates the depth of the qp created, it may have different > implications on > > > >> other PMDs. > > > >> nb_sessions_per_qp and nb_streams_per_qp are limitations the > devices > > > >> reports and are same for all qps on the device. QAT doesn't have > those > > > >> limitations and so would report 0, however I assumed they may be > > > necessary > > > >> for other devices. > > > >> This assumption is based on the patch submitted by NXP to cryptodev > in > > > Feb > > > >> 2017 > > > >> > > > > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdpd > > > k.org%2Fml%2Farchives%2Fdev%2F2017- > > > > March%2F060740.html&data=02%7C01%7Cahmed.mansour%40nxp.com%7C > > > > b012d74d7530493b155108d56258955f%7C686ea1d3bc2b4c6fa92cd99c5c30163 > > > > 5%7C0%7C0%7C636523054981379413&sdata=2SazlEazMxcBGS7R58CpNrX0G5 > > > OeWx8PLMwf%2FYzqv34%3D&reserved=0 > > > >> I also assume these are not necessarily the max number of sessions in > ops > > > on > > > >> the qp at a given time, but the total number attached, i.e. if the > > > >> device > > > has > > > >> this limitation then sessions must be attached to qps, and presumably > > > >> reserve some resources. Being attached doesn't imply there is an op > on > > > the > > > >> qp at that time using that session. So it's not to relating to the > > > >> inflight > op > > > >> count, but to the number of sessions attached/detached to the qp. > > > >> Including Akhil on the To list, maybe NXP can confirm if these params > are > > > >> needed. > > > > [Shally] Ok. Then let's wait for NXP to confirm on this requirement as > > > currently spec doesn't have any API to attach > > > queue_pair_to_specific_session_or_stream as cryptodev. > > > > > > > > But then how application could know limit on max_inflight_ops > supported > > > on a qp? As it can pass any random number during qp_setup(). > > > > Do you believe we need to add a capability field in dev_info to indicate > limit > > > on max_inflight_ops? > > > > > > > > Thanks > > > > Shally > > > [Ahmed] @Fiona This looks ok. max_inflight_ops makes sense. I > understand > > > it as a push back mechanism per qp. We do not have physical limit for > > > number of streams or sessions on a qp in our hardware, so we would > > > return 0 here as well. > > > @Shally in our PMD implementation we do not attach streams or sessions > > > to a particular qp. Regarding max_inflight_ops. I think that limit > > > > [Shally] Ok. We too don't have any such limit defined. So, if these are > redundant fields then can be > > removed until requirement is identified in context of compressdev. > [Fiona] Ok, so it seems we're all agreed to remove max_nb_sessions_per_qp > and > max_nb_streams_per_qp from rte_compressdev_info. > I think we're also agreed to keep max_inflight_ops on the qp_setup.
[Shally] yes, by me. > It's not available on the info and if I understand you both correctly we don't > need to add it there as a hw limitation or capability. [Shally] I'm fine with either ways. No preferences here currently. > I'd expect the appl to set it to > some value which is probably lower than any hardware limitation. The appl > may then > perform many enqueue_bursts until the qp is full and if unable to enqueue a > burst > should try dequeueing to free up space on the qp for more enqueue_bursts. [Shally] qp not necessarily has to be full (depending upon PMD implementation though) to run into this condition, especially when, say, Hw limit < application max_inflight_ops. Thus, would rephrase it as: "application may enqueue bursts up to limit setup in qp_setup and if enqueue_burst() returns with number < total nb_ops , then wait on dequeue to free-up space". > I think the value it's set to can give the application some influence over > latency vs throughput. > E.g. if it's set to a very large number then it allows the PMD to stockpile > requests, > which can result in longer latency, but optimal throughput as easier to keep > the > engines supplied with requests. If set very small, latency may be short, as > requests get > to engines sooner, but there's a risk of the engines running out of requests > if the PMD manages to process everything before the application tops up the > qp. [Shally] I concur from you. > > > > > > > > should be independent of hardware. Not all enqueues must succeed. > The > > > hardware can push back against the enqueuer dynamically if the > resources > > > needed to accommodate additional ops are not available yet. This push > > > back happens in the software if the user sets a max_inflight_ops that is > > > less that the hardware max_inflight_ops. The same return pathway can > be > > > exercised if the user actually attempts to enqueue more than the > > > supported max_inflight_ops because of the hardware. > > > > [Shally] Ok. This sounds fine to me. As you mentioned, we can let > application setup a queue pair with > > any max_inflight_ops and, during enqueue_burst(), leave it on hardware > to consume as much as it can > > subject to the limit set in qp_setup(). > > So, this doesn't seem to be a hard requirement on dev_info to expose. > Only knock-on effect I see is, > > same testcase can then behave differently with different PMDs as each > PMD may have different support > > level for same max_inflight_ops in their qp_setup(). >
