From: "Lu, Wenzhuo" <wenzhuo.lu@intel.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Stephen Hemminger <stephen@networkplumber.org>,
"dev@dpdk.org" <dev@dpdk.org>,
"Richardson, Bruce" <bruce.richardson@intel.com>,
"Chen, Jing D" <jing.d.chen@intel.com>,
"Liang, Cunming" <cunming.liang@intel.com>,
"Wu, Jingjing" <jingjing.wu@intel.com>,
"Zhang, Helin" <helin.zhang@intel.com>,
"thomas.monjalon@6wind.com" <thomas.monjalon@6wind.com>
Subject: Re: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset
Date: Wed, 22 Jun 2016 05:05:14 +0000 [thread overview]
Message-ID: <6A0DE07E22DDAD4C9103DF62FEBC090903489838@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <20160622041431.GA6219@localhost.localdomain>
> -----Original Message-----
> From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> Sent: Wednesday, June 22, 2016 12:15 PM
> 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 reset
>
> On Wed, Jun 22, 2016 at 03:32:16AM +0000, Lu, Wenzhuo wrote:
> > 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 reset
> > >
> > > 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 description.
> > > > > > > > > > > |
> > > > > > > > > > > |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
> configuration.
> > > > > > > > > > >
> > > > > > > > > > > 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 possible.
> > > > > > > > > > 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_stop() 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 generic?
> > > > Any suggestion? I use this name because I believe what this API do
> > > > is to 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-implement 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
> problem.
> > > > > > > >
> > > > > > > > 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
> > > > message 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 receive such kind of message.
> > > > And we use the callback mechanism to let APP notified. APP should
> > > > register a
> > > callback function. When VF driver receives the message it will call
> > > the callback function, then APP can know that.
> > >
> > > 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
> > > handle 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 perspective FLR etc)
> > >
> > > OR
> > >
> > > 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 keep adding new functionality with out introducing new counter
> > > API in VF
> > >
> > > Jerin
> > Lost here. I think these RTE_ETH_EVENTs are used to connect the APP call
> back functions with the events.
> > Actually I want the APP to register a callback function reset_event_callback 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 which is provided by APP. Means reset_event_callback here.
>
> me too. Their is existing RTE_ETH_EVENT_INTR_RESET event to notify the PF
> reset.I guess it is not for the PF link change or it isfor generic VF reset request
> initiated by PF for everything.
I think this event is for device reset not only for PF but also can for VF. I think we can use this event when the driver want the APP to reset the device. The PF link down/up caused VF reset is one of the cases.
>
> file: lib/librte_ether/rte_ethdev.h
> RTE_ETH_EVENT_INTR_RESET,
> /**< reset interrupt event, sent to VF on PF reset */
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> if application need to call rte_ethdev_reset() on RTE_ETH_EVENT_INTR_RESET
> event then please mention it commit log or API description.
Good suggestion. I'll try to find where's the good place to add more explanation.
>
next prev parent reply other threads:[~2016-06-22 5:05 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 5:40 [dpdk-dev] [PATCH 0/8] support reset of VF link Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 1/8] lib/librte_ether: support device reset Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 2/8] lib/librte_ether: defind RX/TX lock mode Wenzhuo Lu
2016-06-08 2:15 ` Stephen Hemminger
2016-06-08 7:34 ` Lu, Wenzhuo
2016-06-09 7:50 ` Olivier Matz
2016-06-12 5:25 ` Lu, Wenzhuo
2016-06-10 18:12 ` Stephen Hemminger
2016-06-12 5:27 ` Lu, Wenzhuo
2016-06-06 5:40 ` [dpdk-dev] [PATCH 3/8] ixgbe: RX/TX with lock on VF Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 4/8] ixgbe: implement device reset " Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 5/8] igb: RX/TX with lock " Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 6/8] igb: implement device reset " Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 7/8] i40e:RX/TX with lock " Wenzhuo Lu
2016-06-06 5:40 ` [dpdk-dev] [PATCH 8/8] i40e: implement device reset " Wenzhuo Lu
2016-06-15 3:03 ` [dpdk-dev] [PATCH v5 0/4] support reset of VF link Wenzhuo Lu
2016-06-15 3:03 ` [dpdk-dev] [PATCH v5 1/4] lib/librte_ether: support device reset Wenzhuo Lu
2016-06-16 15:31 ` Bruce Richardson
2016-06-16 15:36 ` Thomas Monjalon
2016-06-15 3:03 ` [dpdk-dev] [PATCH v5 2/4] ixgbe: implement device reset on VF Wenzhuo Lu
2016-06-15 3:03 ` [dpdk-dev] [PATCH v5 3/4] igb: " Wenzhuo Lu
2016-06-15 3:03 ` [dpdk-dev] [PATCH v5 4/4] i40e: " Wenzhuo Lu
2016-06-20 6:24 ` [dpdk-dev] [PATCH v6 0/4] support reset of VF link Wenzhuo Lu
2016-06-20 6:24 ` [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset Wenzhuo Lu
2016-06-20 9:14 ` Jerin Jacob
2016-06-20 16:17 ` Stephen Hemminger
2016-06-21 3:51 ` Jerin Jacob
2016-06-21 6:14 ` Lu, Wenzhuo
2016-06-21 7:37 ` Jerin Jacob
2016-06-21 8:24 ` Lu, Wenzhuo
2016-06-21 8:55 ` Jerin Jacob
2016-06-21 9:26 ` Ananyev, Konstantin
2016-06-21 10:57 ` Jerin Jacob
2016-06-21 13:10 ` Ananyev, Konstantin
2016-06-21 13:30 ` Jerin Jacob
2016-06-21 14:03 ` Ananyev, Konstantin
2016-06-21 14:29 ` Jerin Jacob
2016-06-22 1:35 ` Lu, Wenzhuo
2016-06-22 2:37 ` Jerin Jacob
2016-06-22 3:32 ` Lu, Wenzhuo
2016-06-22 4:14 ` Jerin Jacob
2016-06-22 5:05 ` Lu, Wenzhuo [this message]
2016-06-22 6:10 ` Jerin Jacob
2016-06-22 6:42 ` Lu, Wenzhuo
2016-06-22 7:59 ` Jerin Jacob
2016-06-22 8:17 ` Thomas Monjalon
2016-06-22 8:25 ` Lu, Wenzhuo
2016-06-22 9:18 ` Thomas Monjalon
2016-06-22 11:06 ` Jerin Jacob
2016-06-23 0:45 ` Lu, Wenzhuo
2016-06-23 0:39 ` Lu, Wenzhuo
2016-06-21 0:51 ` Lu, Wenzhuo
2016-06-20 6:24 ` [dpdk-dev] [PATCH v6 2/4] ixgbe: implement device reset on VF Wenzhuo Lu
2016-06-20 6:24 ` [dpdk-dev] [PATCH v6 3/4] igb: " Wenzhuo Lu
2016-06-20 6:24 ` [dpdk-dev] [PATCH v6 4/4] i40e: " Wenzhuo Lu
2016-07-04 15:48 ` [dpdk-dev] [PATCH v6 0/4] support reset of VF link Luca Boccassi
2016-07-05 0:52 ` Lu, Wenzhuo
2016-07-05 9:52 ` Luca Boccassi
2016-07-06 0:45 ` Lu, Wenzhuo
2016-07-06 16:26 ` Luca Boccassi
[not found] ` <1467822182.32466.34.camel@brocade.com>
2016-07-07 1:09 ` Lu, Wenzhuo
2016-07-07 10:20 ` Luca Boccassi
2016-07-07 13:12 ` Lu, Wenzhuo
2016-07-07 16:19 ` Luca Boccassi
2016-07-08 0:14 ` Lu, Wenzhuo
2016-07-08 17:15 ` Luca Boccassi
2016-07-11 1:32 ` Lu, Wenzhuo
2016-07-11 12:02 ` Luca Boccassi
2016-07-11 15:43 ` Luca Boccassi
2016-07-12 1:19 ` Lu, Wenzhuo
2016-08-26 12:58 ` Luca Boccassi
2016-08-29 1:04 ` Lu, Wenzhuo
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