Re: [PATCH v6 1/4] lib/librte_ether: support device reset

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

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@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?

How about calling it as rte_eth_dev_restart() ?

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.

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.