> -----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. Konstantin
