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

[John Daley (johndale)]

Hi,
Inline.
Thanks,
John

> -----Original Message-----
> From: Thomas Monjalon <thomas at monjalon.net>
> Sent: Friday, March 30, 2018 6:48 AM
> 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) <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
>