[dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset

[Lu, Wenzhuo]

Hi Jerin,


> -----Original Message-----
> From: Jerin Jacob [mailto:jerin.jacob at caviumnetworks.com]
> Sent: Wednesday, June 22, 2016 7:07 PM
> To: Thomas Monjalon
> Cc: Lu, Wenzhuo; dev at dpdk.org; Ananyev, Konstantin; Stephen Hemminger;
> Richardson, Bruce; Chen, Jing D; Liang, Cunming; Wu, Jingjing; Zhang, Helin
> Subject: Re: [dpdk-dev] [PATCH v6 1/4] lib/librte_ether: support device reset
> 
> On Wed, Jun 22, 2016 at 11:18:21AM +0200, Thomas Monjalon wrote:
> > 2016-06-22 08:25, Lu, Wenzhuo:
> > > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> > > > 2016-06-22 13:29, Jerin Jacob:
> > > > > Thomas,
> > > > > As a librte_ether maintainer any comments on this?
> > > >
> > > > +1 for adding details and make sure naming is good.
> > > > I don't really need to comment here because I have already done
> > > > this comment
> > > > earlier:
> > > > 	http://dpdk.org/ml/archives/dev/2016-June/041845.html
> > > > Thank you for insisting.
> > > I've add some details in this patch set. If it's not enough, please let me know.
> > > And I think this discussion is about what the API name should be like. Actually
> I think all the existing name is describing what is done by the API not when and
> where it should be used, like dev_start/stop.
> >
> > You're right, I overlooked it:
> >
> > + * The API will stop the port, clear the rx/tx queues, re-setup the
> > + rx/tx
> > + * queues, restart the port.
> >
> > Jerin, which detail do you think is needed?
> 
> When to use what ? In what scenarios application need to use generic stop/start
> vs this new API?
I'll add more explanation. Actually I've written an example. But after discussion we agree it's not a good idea to add a totally new example just for one function. I'm thinking about now to fuse this example into testpmd.

> 
> How about calling it as rte_eth_dev_restart() ?
Sounds good :)

> 
> If existing stop and then start is same the new API in functional perspective, How
> about having generic implementation of rte_eth_dev_restart() if PMD specific
> restart handlers are NOT found.
Good suggestion, thanks.

> 
> That why application need to call only rte_eth_dev_restart() for port restart. It
> can internally decide optimized stop/start or generic restart
> 
> Jerin
> 
> >
> > Wenzhuo, why this function is needed?
> > All these actions are already possible independently.
> > When looking at ixgbe implementation, I see:
> > 	ixgbevf_dev_stats_reset() which is not documented in the API
> > 	rte_delay_ms(1000);
> > 	do {} while
> > It looks to be some hacks.
> > If you really need some workarounds to handle some tricky situations,
> > maybe that the API is not detailed enough.
> >
> > > But anyway I'm open for changing the name. Is the name process_reset_intr
> you prefer? Thanks.
> >
> > Not sure.
> > If you really intend to add a generic reset, maybe rte_eth_dev_reset()
> > is a good name. We just need more justification.
> > After reading the doc, the user can understand it is just a wrapper of
> > existing functions. But it appears in the code that it does more and
> > can help in some situations.