On 4/24/2018 4:20 PM, Ananyev, Konstantin wrote: > > >> -----Original Message----- >> From: Yigit, Ferruh >> Sent: Tuesday, April 24, 2018 1:28 PM >> To: Ananyev, Konstantin <[email protected]>; Thomas Monjalon >> <[email protected]>; [email protected] >> Cc: Ajit Khaparde <[email protected]>; Jerin Jacob >> <[email protected]>; Shijith Thotton >> <[email protected]>; Santosh Shukla >> <[email protected]>; Rahul Lakkireddy >> <[email protected]>; John Daley <[email protected]>; Lu, Wenzhuo >> <[email protected]>; Xing, Beilei >> <[email protected]>; Zhang, Qi Z <[email protected]>; Wu, Jingjing >> <[email protected]>; Adrien Mazarguil >> <[email protected]>; Nelio Laranjeiro <[email protected]>; >> Yongseok Koh <[email protected]>; Shahaf Shuler >> <[email protected]>; Tomasz Duszynski <[email protected]>; Jianbo Liu >> <[email protected]>; Alejandro Lucero >> <[email protected]>; Hemant Agrawal <[email protected]>; >> Shreyansh Jain <[email protected]>; Harish >> Patil <[email protected]>; Rasesh Mody <[email protected]>; >> Andrew Rybchenko <[email protected]>; >> Shrikrishna Khare <[email protected]>; Maxime Coquelin >> <[email protected]>; Legacy, Allain (Wind River) >> <[email protected]>; Richardson, Bruce >> <[email protected]>; Gaetan Rivet <[email protected]>; Olivier >> Matz >> <[email protected]> >> Subject: Re: [dpdk-dev] Survey for final decision about per-port offload API >> >> On 4/24/2018 12:08 PM, Ananyev, Konstantin wrote: >>> Hi Ferruh, >>> >>>> >>>> On 3/30/2018 2:47 PM, Thomas Monjalon wrote: >>>>> 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? >>>> >>>> There is a detail of ability to disabling queue level offloads in >>>> queue_setup() >>>> function, I want to discuss here. >>>> >>>> Prolog: >>>> port level offload: An offload only can be applied port level, to all >>>> queues. >>>> queue level offload: An offload can be applied into individual queues of >>>> the port >>>> >>>> PMD reports port offload capability: port level offload + queue level >>>> offload >>>> PMD reports queue offload capability: queue level offload >>>> >>>> >>>> Above suggested change to API: >>>> - Application will be limited in configure() to set only an offload within >>>> "port >>>> offload capability" >>>> - Application will be limited in queue_setup() to set only an offload >>>> within >>>> "queue offload capability" >>>> >>>> >>>> This doesn't say much about disabling an offload in queue_setup(), as a >>>> rule: >>>> - An "port level offload" can't be disabled in queue_setup() >>>> >>>> >>>> There are two cases of disable: >>>> 1- Disabling a "queue level offload" enabled queue_setup() previously >>>> 2- Disabling a "queue level offload" enabled in configure() >>>> >>>> If second is not supported, to disable the offload, applications should >>>> stop->re-configure()->re-queue_setup()->start the port. But having this >>>> capability makes the offloading parameters more confusing for applications. >>>> >>>> >>>> I suggest adding disable support to fist one but not second one. >>> >>> Not sure why to introduce such limitation? >> >> Not supporting second one? >> >> To differentiate disable request for that case is harder. How can we say to >> disable a "queue level offloads" enabled by configure()? >> >> It may be by setting these offloads in queue_setup() as well and when any >> offload is missing in queue_setup() it can be taken as disable request. This >> forces applications to duplicate/set "queue level offloads" enabled by >> configure() in the queue_setup() function by default. >> >> This is an option, but my concern was to this may be harder to manage by >> applications. >> An application will have to remove "port level offload" from port_offloads >> and >> feed it into each queue_setup(). >> >> Also this is closer to existing API but not same, the difference is >> queue_setup() doesn't get "port level offload" >> >> We can go with this one if there is a requirement for it. >> >> And if we prefer to go with this option, perhaps we can think twice about >> changing exiting API because this will be very close the existing API. Only >> logically it is not correct to force application to set some offloads in >> queue_setup() for the PMD that doesn't support queue offload at all, this >> can be >> handled in PMD, and saves us of all the trouble of the change. > > I suppose both ways are possible - though if we don't allow user to disable > queue-specific > offload on particular queue, we would end up with most users just not > specifying > any queue-specific offloads at configure() at all - just to have an ability > to disable it in future > for particular queue.
Yes, this has been mentioned as a easier option to go previously. > > Konstantin > >
