[dpdk-dev] Survey for final decision about per-port offload API

[Jerin Jacob]

-----Original Message-----
> Date: Fri, 30 Mar 2018 15:47:55 +0200
> From: Thomas Monjalon <thomas at monjalon.net>
> To: dev at dpdk.org
> Cc: Ajit Khaparde <ajit.khaparde at broadcom.com>, Jerin Jacob
>  <jerin.jacob at caviumnetworks.com>, Shijith Thotton
>  <shijith.thotton at cavium.com>, Santosh Shukla
>  <santosh.shukla at caviumnetworks.com>, Rahul Lakkireddy
>  <rahul.lakkireddy at chelsio.com>, John Daley <johndale at cisco.com>, Wenzhuo
>  Lu <wenzhuo.lu at intel.com>, Konstantin Ananyev
>  <konstantin.ananyev at intel.com>, Beilei Xing <beilei.xing at intel.com>, Qi
>  Zhang <qi.z.zhang at intel.com>, Jingjing Wu <jingjing.wu at intel.com>, Adrien
>  Mazarguil <adrien.mazarguil at 6wind.com>, Nelio Laranjeiro
>  <nelio.laranjeiro at 6wind.com>, Yongseok Koh <yskoh at mellanox.com>, Shahaf
>  Shuler <shahafs at mellanox.com>, Tomasz Duszynski <tdu at semihalf.com>, Jianbo
>  Liu <jianbo.liu at arm.com>, Alejandro Lucero
>  <alejandro.lucero at netronome.com>, Hemant Agrawal <hemant.agrawal at nxp.com>,
>  Shreyansh Jain <shreyansh.jain at nxp.com>, Harish Patil
>  <harish.patil at cavium.com>, Rasesh Mody <rasesh.mody at cavium.com>, Andrew
>  Rybchenko <arybchenko at solarflare.com>, Shrikrishna Khare
>  <skhare at vmware.com>, Maxime Coquelin <maxime.coquelin at redhat.com>, Allain
>  Legacy <allain.legacy at windriver.com>, Bruce Richardson
>  <bruce.richardson at intel.com>, Gaetan Rivet <gaetan.rivet at 6wind.com>,
>  Olivier Matz <olivier.matz at 6wind.com>
> Subject: Survey for final decision about per-port offload API
> 
> There are some discussions about a specific part of the offload API:
> 	"To enable per-port offload, the offload should be set on both
> 	device configuration and queue setup."
> 
> It means the application must repeat the port offload flags
> in rte_eth_conf.[rt]xmode.offloads and rte_eth_[rt]xconf.offloads,
> when calling respectively rte_eth_dev_configure() and
> rte_eth_[rt]x_queue_setup for each queue.
> 
> The PMD must check if there is mismatch, i.e. a port offload not
> repeated in queue setup.
> There is a proposal to do this check at ethdev level:
> 	http://dpdk.org/ml/archives/dev/2018-March/094023.html
> 
> It was also proposed to relax the API and allow "forgetting" port
> offloads in queue offloads:
> 	http://dpdk.org/ml/archives/dev/2018-March/092978.html
> 
> It would mean the offloads applied to a queue result of OR operation:
> 	rte_eth_conf.[rt]xmode.offloads | rte_eth_[rt]xconf.offloads
> 
> 1/ Do you agree with above API change?

Yes.

> 
> 
> If we agree with this change, we need to update the documentation
> and remove the checks in PMDs.
> Note: no matter what is decided here, 18.05-rc1 should have all PMDs
> switched to the API which was defined in 17.11.
> Given that API is new and not yet adopted by the applications,
> the sonner it is fixed, the better.
> 
> 2/ Should we do this change in 18.05-rc2?

Yes.

> 
> 
> At the same time, we want to make clear that an offload enabled at
> port level, cannot be disabled at queue level.
> 
> 3/ Do you agree with above statement (to be added in the doc)?

Yes.

> 
> 
> There is the same kind of confusion in the offload capabilities:
> 	rte_eth_dev_info.[rt]x_offload_capa
> 	rte_eth_dev_info.[rt]x_queue_offload_capa
> The queue capabilities must be a subset of port capabilities,
> i.e. every queue capabilities must be reported as port capabilities.
> But the port capabilities should be reported at queue level
> only if it can be applied to a specific queue.
> 
> 4/ Do you agree with above statement (to be added in the doc)?

Yes

> 
> 
> Please give your opinion on questions 1, 2, 3 and 4.
> Answering by yes/no may be sufficient in most cases :)
> Thank you
> 
>