From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: "Lu, Wenzhuo" <wenzhuo.lu@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: Tue, 21 Jun 2016 14:03:15 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB97725836B7433B@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <20160621133041.GA7509@localhost.localdomain>
> -----Original Message-----
> From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> Sent: Tuesday, June 21, 2016 2:31 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 01:10:40PM +0000, Ananyev, Konstantin wrote:
> >
> >
> > >
> > > Hi Konstantin,
> > >
> > > > Hi Jerin,
> > > >
> > > > > -----Original Message-----
> > > > > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> > > > > Sent: Tuesday, June 21, 2016 9:56 AM
> > > > > To: Lu, Wenzhuo
> > > > > Cc: Stephen Hemminger; dev@dpdk.org; Ananyev, Konstantin; 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 08:24:36AM +0000, Lu, Wenzhuo wrote:
> > > > > > Hi Jerin,
> > > > >
> > > > > 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?
>
> >
> > >
> > >
> > > > 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?
In case of course they do need to handle similar event.
if not I suppose there is no harm to left it unimplemented.
Konstantin
next prev parent reply other threads:[~2016-06-21 14:03 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2601191342CEEE43887BDE71AB97725836B7433B@irsmsx105.ger.corp.intel.com \
--to=konstantin.ananyev@intel.com \
--cc=bruce.richardson@intel.com \
--cc=cunming.liang@intel.com \
--cc=dev@dpdk.org \
--cc=helin.zhang@intel.com \
--cc=jerin.jacob@caviumnetworks.com \
--cc=jing.d.chen@intel.com \
--cc=jingjing.wu@intel.com \
--cc=stephen@networkplumber.org \
--cc=thomas.monjalon@6wind.com \
--cc=wenzhuo.lu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).