-----Original Message----- > Date: Tue, 11 Jul 2017 14:36:57 +0000 > From: "Dai, Wei" <wei....@intel.com> > To: Jerin Jacob <jerin.ja...@caviumnetworks.com> > CC: "tho...@monjalon.net" <tho...@monjalon.net>, "Lu, Wenzhuo" > <wenzhuo...@intel.com>, "Ananyev, Konstantin" > <konstantin.anan...@intel.com>, "Wu, Jingjing" <jingjing...@intel.com>, > "Xing, Beilei" <beilei.x...@intel.com>, "dev@dpdk.org" <dev@dpdk.org> > Subject: RE: [dpdk-dev] [PATCH v6 1/4] ethdev: add support of NIC reset > > > -----Original Message----- > > From: Jerin Jacob [mailto:jerin.ja...@caviumnetworks.com] > > Sent: Tuesday, July 11, 2017 1:17 PM > > To: Dai, Wei <wei....@intel.com> > > Cc: tho...@monjalon.net; Lu, Wenzhuo <wenzhuo...@intel.com>; > > Ananyev, Konstantin <konstantin.anan...@intel.com>; Wu, Jingjing > > <jingjing...@intel.com>; Xing, Beilei <beilei.x...@intel.com>; > > dev@dpdk.org > > Subject: Re: [dpdk-dev] [PATCH v6 1/4] ethdev: add support of NIC reset > > > > -----Original Message----- > > > Date: Tue, 11 Jul 2017 01:57:15 +0000 > > > From: "Dai, Wei" <wei....@intel.com> > > > To: Jerin Jacob <jerin.ja...@caviumnetworks.com> > > > CC: "tho...@monjalon.net" <tho...@monjalon.net>, "Lu, Wenzhuo" > > > <wenzhuo...@intel.com>, "Ananyev, Konstantin" > > > <konstantin.anan...@intel.com>, "Wu, Jingjing" > > > <jingjing...@intel.com>, "Xing, Beilei" <beilei.x...@intel.com>, > > > "dev@dpdk.org" <dev@dpdk.org> > > > Subject: RE: [dpdk-dev] [PATCH v6 1/4] ethdev: add support of NIC > > > reset > > > > > > > > > > + * A DPDK application also can call this function to trigger an > > > > + initative > > > > + * port reset. > > > > > > When apart from the above use case? Even if it is above case, we should > > have some event to notify application to initiate the reset.Right? Without > > the event, When or on what basics application needs to initiate reset? > > > [Wei: Indeed, until now we didn't see any use case which DPDK application > > initiative port reset itself. > > > The most usual case is that PF is working with kernel driver and VFs are > > working with DPDK PMD. > > > Some operations on kernel PF lead to a PF reset which causes its VF reset. > > > Anyway this new function provides a possibility for application to > > > trigger an initiative port reset.] > > > > That's fine. The only concern part is when to call reset API from > > application. > > Can we say on RTE_ETH_EVENT_INTR_RESET event, application needs to > > call the reset API? I think, it is important to specify when application > > need to > > call this API, otherwise this api behavior will be tightly coupled with > > underneath PMD. Side effect is, a new, non portable PMD specific API. > > If a PMD wishes to fixup some overflow case(as an example), by invoking the > > reset API from the application BUT same case may not valid for another > > PMD hence it will create unexpected behavior from application based on the > > underneath PMD. > It is duty of PMD to trigger RTE_ETH_EVENT_INTR_RESET event and application > should also register some callback function to handle this event. > When PMD wants to trigger a reset, it can trigger RTE_ETH_EVENT_INTR_RESET. > On the received event of RTE_ETH_EVENT_INTR_RESET, application can begin to > handle it: stop working queues, make rx and tx function not be called > and then call rte_eth_dev_reset( ). > For thread safety, all these controlling operations had better be made in > same thread. > For example, when ixgbe PF is reset, PF send a message to notify VF this > event and > also trigger an interrupt to VF. And then in the interrupt service routine > DPDK VF > detect this notification message and calls > _rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_INTR_RESET, NULL, NULL). > So it means that PF reset trigger RTE_ETH_EVENT_INTR_RESET event in VF. > The function _rte_eth_dev_callback_process( ) will call the registered > callback function. > The callback function can trigger application to handle all operations of VF > reset including > something like stopping working Rx/Tx queues and call this > rte_eth_dev_reset(). > The rte_eth_dev_reset( ) itself is generic function which only does some HW > reset operations > through calling dev_unint() and dev_init(). And itself doesn't handle above > synchronization which > is handled by application. > PMD itself should not call rte_eth_dev_reset( ). PMD can trigger application > to handle reset event. > It is duty of application to handle all synchronization befort it calls > rte_eth_dev_reset( ).
No disagreement on the expected behavior. > > > > > if RTE_ETH_EVENT_INTR_RESET event is not expected event to call the reset > > API then create a new event or if it needs to be called in > > RTE_ETH_EVENT_INTR_RESET then update the API documentation. > > > Of course, when PMD wants to trigger a reset event, it can trigger other > event other than > RTE_ETH_EVENT_INTR_RESET. So the application should know which the alternate > event is. > This make application more complex. So it is suggested that only > RTE_ETH_EVENT_INTR_RESET > can be used to trigger a port reset. Yes. I suggest to add this info on documentation. ie "application invokes the reset API on RTE_ETH_EVENT_INTR_RESET event". That will answer "when" application need to invoke this API. > > > > > > > > + *
