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

[Wu, Jingjing]

> -----Original Message-----
> From: Thomas Monjalon [mailto: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>;
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> <rahul.lakkireddy at chelsio.com>; John Daley <johndale at cisco.com>; Lu, Wenzhuo
> <wenzhuo.lu at intel.com>; Ananyev, Konstantin <konstantin.ananyev at intel.com>; Xing,
> Beilei <beilei.xing at intel.com>; Zhang, Qi Z <qi.z.zhang at intel.com>; Wu, Jingjing
> <jingjing.wu at intel.com>; Adrien Mazarguil <adrien.mazarguil at 6wind.com>; Nelio
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> 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
 
Thanks
Jingjing

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