From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id 94808B40D for ; Wed, 22 Jun 2016 05:32:19 +0200 (CEST) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 21 Jun 2016 20:32:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,508,1459839600"; d="scan'208";a="992596183" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by fmsmga001.fm.intel.com with ESMTP; 21 Jun 2016 20:32:19 -0700 Received: from FMSMSX109.amr.corp.intel.com (10.18.116.9) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.248.2; Tue, 21 Jun 2016 20:32:18 -0700 Received: from shsmsx151.ccr.corp.intel.com (10.239.6.50) by fmsmsx109.amr.corp.intel.com (10.18.116.9) with Microsoft SMTP Server (TLS) id 14.3.248.2; Tue, 21 Jun 2016 20:32:17 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.147]) by SHSMSX151.ccr.corp.intel.com ([169.254.3.230]) with mapi id 14.03.0248.002; Wed, 22 Jun 2016 11:32:16 +0800 From: "Lu, Wenzhuo" To: Jerin Jacob CC: "Ananyev, Konstantin" , Stephen Hemminger , "dev@dpdk.org" , "Richardson, Bruce" , "Chen, Jing D" , "Liang, Cunming" , "Wu, Jingjing" , "Zhang, Helin" , "thomas.monjalon@6wind.com" Thread-Topic: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset Thread-Index: AQHRyrx6NqZsK6LoQ0Kr0EDRoXtySZ/xjKGAgAB2MwCAAMH0gIAAqwkw//+UC4CAAIsykP//irIAgAAIkQCAABmdAIAAJRoAgAAFmQCAAAkYgIAAB1CAgAE5dBD//5INgAASMuVg Date: Wed, 22 Jun 2016 03:32:16 +0000 Message-ID: <6A0DE07E22DDAD4C9103DF62FEBC0909034897FC@shsmsx102.ccr.corp.intel.com> References: <20160621073710.GA30638@localhost.localdomain> <6A0DE07E22DDAD4C9103DF62FEBC090903488F5E@shsmsx102.ccr.corp.intel.com> <20160621085531.GA31880@localhost.localdomain> <2601191342CEEE43887BDE71AB97725836B73FD0@irsmsx105.ger.corp.intel.com> <20160621105751.GA737@localhost.localdomain> <2601191342CEEE43887BDE71AB97725836B74226@irsmsx105.ger.corp.intel.com> <20160621133041.GA7509@localhost.localdomain> <2601191342CEEE43887BDE71AB97725836B7433B@irsmsx105.ger.corp.intel.com> <20160621142924.GA8670@localhost.localdomain> <6A0DE07E22DDAD4C9103DF62FEBC09090348971F@shsmsx102.ccr.corp.intel.com> <20160622023745.GA4437@localhost.localdomain> In-Reply-To: <20160622023745.GA4437@localhost.localdomain> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Jun 2016 03:32:20 -0000 Hi Jerin, > -----Original Message----- > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com] > Sent: Wednesday, June 22, 2016 10:38 AM > To: Lu, Wenzhuo > Cc: Ananyev, Konstantin; Stephen Hemminger; dev@dpdk.org; Richardson, > Bruce; Chen, Jing D; Liang, Cunming; Wu, Jingjing; Zhang, Helin; > thomas.monjalon@6wind.com > Subject: Re: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device r= eset >=20 > On Wed, Jun 22, 2016 at 01:35:37AM +0000, Lu, Wenzhuo wrote: > > Hi Jerin, > > > > > -----Original Message----- > > > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com] > > > Sent: Tuesday, June 21, 2016 10:29 PM > > > To: Ananyev, Konstantin > > > Cc: Lu, Wenzhuo; Stephen Hemminger; dev@dpdk.org; Richardson, Bruce; > > > Chen, Jing D; Liang, Cunming; Wu, Jingjing; Zhang, Helin; > > > thomas.monjalon@6wind.com > > > Subject: Re: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support > > > device reset > > > > > > On Tue, Jun 21, 2016 at 02:03:15PM +0000, Ananyev, Konstantin wrote: > > > > > > > > > > > > > > > > > Hi Wenzhuo, > > > > > > > > > > > > > > > > > > > > > > > > On Mon, Jun 20, 2016 at 02:24:27PM +0800, > > > > > > > > > > > > > > > Wenzhuo Lu > > > wrote: > > > > > > > > > > > > > > > > Add an API to reset the device. > > > > > > > > > > > > > > > > It's for VF device in this scenario, kernel= PF + DPDK VF. > > > > > > > > > > > > > > > > When the PF port down->up, APP should call > > > > > > > > > > > > > > > > this API to reset VF port. Most likely, > > > > > > > > > > > > > > > > APP should call it in its management > > > > > > > > > > > > > > > > thread and guarantee the thread safe. It > > > > > > > > > > > > > > > > means APP should stop the rx/tx and the > > > > > > > > > > > > > > > > device, then reset the device, then > > > recover the device and rx/tx. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Following is _a_ use-case for Device reset. > > > > > > > > > > > > > > > But may be not be _the_ use case. IMO, We > > > > > > > > > > > > > > > need to first say expected behavior of this > > > > > > > > > > > > > > > API and add a use-case > > > later. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Other use-case would be, PCIe VF with > > > > > > > > > > > > > > > functional level reset for SRIOV migration. > > > > > > > > > > > > > > > Are we on same page? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > In my experience with Linux devices, this is > > > > > > > > > > > > > > normally handled by the device driver in the > > > > > > > > > > > > > > start routine. Since any use case which needs > > > > > > > > > > > > > > this is going to do a stop/reset/start > > > > > > > > > > > > > > sequence, why not just have > > > the VF device driver do this in the start routine?. > > > > > > > > > > > > > > > > > > > > > > > > > > > > Adding yet another API and state transistion > > > > > > > > > > > > > > if not necessary increases the complexity and > > > > > > > > > > > > > > required test > > > cases for all devices. > > > > > > > > > > > > > > > > > > > > > > > > > > I agree with Stephen here.I think if application > > > > > > > > > > > > > needs to call start after the device reset then > > > > > > > > > > > > > we could add this logic in start itself rather > > > > > > > > > > > > > exposing a yet another API > > > > > > > > > > > > Do you mean changing the device_start to include > > > > > > > > > > > > all these actions, stop > > > > > > > > > > > device -> stop queue -> re-setup queue -> start > > > > > > > > > > > queue -> start > > > device ? > > > > > > > > > > > > > > > > > > > > > > What was the expected API call sequence when you > > > > > > > > > > > were > > > introduced this API? > > > > > > > > > > > > > > > > > > > > > > Point was to have implicit device reset in the API > > > > > > > > > > > call sequence(Wherever make sense for specific PMD) > > > > > > > > > > I think the API call sequence depends on the > > > > > > > > > > implementation of the APP. Let's say if there's not > > > > > > > > > > this reset API, APP can use > > > > > this > > > > > > > API > > > > > > > > > call sequence to handle the PF link down/up event, > > > > > > > > > rte_eth_dev_close -> rte_eth_rx_queue_setup -> > > > > > rte_eth_tx_queue_setup - > > > > > > > > > > > > > > > > > rte_eth_dev_start. > > > > > > > > > > Actually our purpose is to use this reset API instead > > > > > > > > > > of the API call sequence. You can see the reset API is > > > > > > > > > > not necessary. The > > > > > > > benefit > > > > > > > > > is to save the code for APP. > > > > > > > > > > > > > > > > > > Then I am bit confused with original commit log descripti= on. > > > > > > > > > | > > > > > > > > > |It means APP should stop the rx/tx and the device, then > > > > > > > > > |reset the device, then recover the device and rx/tx. > > > > > > > > > | > > > > > > > > > I was under impression that it a low level reset API for > > > > > > > > > this device? Is n't it? > > > > > > > > > > > > > > > > > > The other issue is generalized outlook of the API, > > > > > > > > > Certain PMD will not have PF link down/up event? Link > > > > > > > > > down/up and only connected to VF and PF only for configur= ation. > > > > > > > > > > > > > > > > > > How about fixing it more transparently in PMD driver > > > > > > > > > itself as PMD driver knows the PF link up/down event, Is > > > > > > > > > it possible to recover the VF on that event if its only > > > > > > > > > matter of resetting > > > it? > > > > > > > > > > > > > > > > I think we already went through that discussion on the list= . > > > > > > > > Unfortunately with current dpdk design it is hardly possibl= e. > > > > > > > > To achieve that we need to introduce some sort of > > > > > > > > synchronisation between IO and control APIs (locking or so)= . > > > > > > > > Actually I am not sure why having a special reset function > > > > > > > > will be a > > > problem. > > > > > > > > > > > > > > | > > > > > > > |It means APP should stop the rx/tx and the device, then > > > > > > > |reset the device, then recover the device and rx/tx. > > > > > > > | > > > > > > > Just to understand, If application still need to do the > > > > > > > stop then what value addtion reset API brings on the table? > > > > > > > > > > > > If application calls dev_reset() it doesn't need to call dev_st= op() before > it. > > > > > > dev_reset() will take care of it. > > > > > > But it needs to make sure that no other thread will try to > > > > > > modify that device state (either dev_stop/start, or > > > > > > eth_rx_busrst/eth_tx_burst) > > > while the reset op is in place. > > > > > > > > > > OK. This description looks different than commit log and API > > > > > doxygen > > > comment. Please fix it. > > > > > How about a different name for this API. Device reset is too gene= ric? > > Any suggestion? I use this name because I believe what this API do is t= o reset > the device. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Yes, it would exist only for VFs, for PF it could be left > unimplemented. > > > > > > > > Though it definitely seems more convenient from user point > > > > > > > > of view, they would know: to handle VF reset event, they > > > > > > > > just need to call that particular function, not to re-imple= ment their > own. > > > > > > > What if driver returns "not implemented" then application > > > > > > >will have do generic rte_eth_dev_stop/rte_eth_dev_start. > > > > > > >That way in application perspective we are NOT solving any pr= oblem. > > > > > > > > > > > > True, but as I said for PF application would just never receive= such event. > > > > > What is this event ? Is it VF Link up/down event? > > > > > > > > > > No I was referring to VF itself, Other VF PMD drivers in > > > > > drivers/net where this callback is not implemented. > > > > > > > > Hmm, the only suggestion I have here - Maintainers/developers of > > > > non-Intel PMD will implement it for their VFs? > > > > > > That's fine. But, We have to know what to implement here in PMD > perspective? > > > That's reason being asking about the API expectation and application > > > usage :-) > > > > > > > In case of course they do need to handle similar event. > > > Which is this event and How application get notify it. > > When the PF link is down/up, the PF will use the mailbox to send a mess= age to > VF. The event here means the VF receives that message from PF. So VF can = know > the physical link state changed. You see it's only for VF. PF will not re= ceive such > kind of message. > > And we use the callback mechanism to let APP notified. APP should regis= ter a > callback function. When VF driver receives the message it will call the c= allback > function, then APP can know that. >=20 > How about the standardizing a name for that event like > RTE_ETH_EVENT_INTR_DOWNSTREAM_LSC or RTE_ETH_EVENT_INTR_PF_LSC > or similar (like RTE_ETH_EVENT_INTR_RESET) and counter API in VF to handl= e > the specific event whose API name similar to selected event name not > eth_dev_reset(reset sounds like more like HW reset, In PCIe device perspe= ctive > FLR etc) >=20 > OR >=20 > How about handling in more generic way where a generic alert message send= by > PF to VF like RTE_ETH_EVENT_INTR_PF_ALERT or similar. > And have only one handle functions in VF side so that in future we can ke= ep > adding new functionality with out introducing new counter API in VF >=20 > Jerin Lost here. I think these RTE_ETH_EVENTs are used to connect the APP call ba= ck functions with the events. Actually I want the APP to register a callback function reset_event_callbac= k for the reset event. Like this, /* register reset interrupt callback */ rte_eth_dev_callback_register(portid, RTE_ETH_EVENT_INTR_RESET, reset_event_callback, NULL); And when the VF driver finds PF link down/up, it should use _rte_eth_dev_= callback_process(dev, RTE_ETH_EVENT_INTR_RESET) to run into the callback wh= ich is provided by APP. Means reset_event_callback here. >=20 > > > > > > > > > if not I suppose there is no harm to left it unimplemented. > > > OK. If it is for VF/PF link down-up event then I will make it as 'nop= '. > > As explained above, the event is not VF/PF link down-up. Actually it's = that VF is > notified the PF link is down-up. > > > > And to my opinion, although now we only implement the reset API for VF,= I > believe there's nothing preventing us to implement this API for PF if we = can find > some scenario that we need to reset the PF link. The reset API is reset A= PI, it can > be used for the event described above. But it's not bound to this event. > > > > > > Jerin > > > > > > > Konstantin > > > >