From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: Ciara Loftus <ciara.loftus@intel.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] net/vhost: Add function to retreive the 'vid' for a given port id
Date: Thu, 22 Sep 2016 10:36:50 +0800 [thread overview]
Message-ID: <20160922023650.GK23158@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <1673736.mOMazzh4h1@xps13>
On Wed, Sep 21, 2016 at 03:07:51PM +0200, Thomas Monjalon wrote:
> 2016-09-18 16:27, Yuanhan Liu:
> > On Wed, Sep 14, 2016 at 10:35:53AM +0200, Thomas Monjalon wrote:
> > > 2016-09-14 15:21, Yuanhan Liu:
> > > > On Wed, Sep 14, 2016 at 09:10:48AM +0200, Thomas Monjalon wrote:
> > > > > 2016-09-14 12:43, Yuanhan Liu:
> > > > > > On Tue, Sep 13, 2016 at 05:10:09PM +0200, Thomas Monjalon wrote:
> > > > > > > 2016-09-13 14:47, Ciara Loftus:
> > > > > > > > In some cases when using the vHost PMD, certain vHost library functions
> > > > > > > > may still need to be accessed. One such example is the
> > > > > > > > rte_vhost_get_queue_num function which returns the number of virtqueues
> > > > > > > > reported by the guest - information which is not exposed by the PMD.
> > > > > > > >
> > > > > > > > This commit introduces a new rte_eth_vhost function that returns the
> > > > > > > > 'vid' associated with a given port id. This allows the PMD user to call
> > > > > > > > vHost library functions which require the 'vid' value.
> > > > > > >
> > > > > > > I think we should not add any API to the PMDs.
> > > > > >
> > > > > > In general, I agree with you.
> > > > > >
> > > > > > > Maybe you are looking for a generic API in ethdev.
> > > > > >
> > > > > > But maybe it's a bit hard to define a "right" generic API here. For this
> > > > > > case, the generic API I can think of could be:
> > > > > >
> > > > > > - an API to get queue num, like rte_eth_get_queue_enabled_num
> > > > > > I barely know NIC pmd drivers, but I doubt it's useful/meaningful for them.
> > > > > >
> > > > > > - an API to get a PMD driver private (or specific) data.
> > > > > > For vhost-pmd, it's vid. Again, I don't know what it could be for other nic
> > > > > > drivers.
> > > > > >
> > > > > > This one may be a better option here, because it expose a key field to
> > > > > > the application, vid, with which the application can invoke more vhost
> > > > > > APIs. And apparently, it's not feasible to try to define a generic API
> > > > > > for some (if not each) vhost APIs.
> > > > >
> > > > > There could be a similar need in other PMD.
> > > > > If we can get an opaque identifier of the device which is not the port id,
> > > > > we could call some specific functions of the driver not implemented in
> > > > > the generic ethdev API.
> > > >
> > > > That means you have to add/export the PMD API first. Isn't it against what
> > > > you are proposing -- "I think we should not add any API to the PMDs" ;)
> > >
> > > Yes you are totally right :)
> > > Except that in vhost case, we would not have any API in the PMD.
> > > But it would allow to have some specific API in other PMDs for the features
> > > which do not fit in a generic API.
> >
> > So, does that mean you are okay with this patch now? I mean, okay to introduce
> > a vhost PMD API?
>
> It means I would be in favor of introducing API in drivers for very specific
> features.
> In this case, I am not sure that retrieving an internal id is very specific.
It's not, instead, it's very generic. The "internal id" is actually the
public interface to vhost-user application, like "fd" to file APIs.
Instead of introducing a few specific wrappers/APIs, I'd prefer to
introduce a generic one to get the handle, and let the application to
call other vhost APIs.
--yliu
next prev parent reply other threads:[~2016-09-22 2:36 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 13:47 Ciara Loftus
2016-09-13 15:10 ` Thomas Monjalon
2016-09-14 4:43 ` Yuanhan Liu
2016-09-14 7:10 ` Thomas Monjalon
2016-09-14 7:21 ` Yuanhan Liu
2016-09-14 8:35 ` Thomas Monjalon
2016-09-18 8:27 ` Yuanhan Liu
2016-09-21 13:07 ` Thomas Monjalon
2016-09-22 2:36 ` Yuanhan Liu [this message]
2016-09-22 16:43 ` Thomas Monjalon
2016-09-23 4:26 ` Yuanhan Liu
2016-09-23 8:43 ` Thomas Monjalon
2016-09-23 9:16 ` Yuanhan Liu
2016-09-23 9:26 ` Loftus, Ciara
2016-09-23 21:23 ` Wiles, Keith
2016-09-26 3:19 ` Yuanhan Liu
2016-09-26 13:12 ` Thomas Monjalon
2016-09-26 13:18 ` Bruce Richardson
2016-09-26 14:26 ` Thomas Monjalon
2016-09-26 14:34 ` Bruce Richardson
2016-09-26 16:24 ` Iremonger, Bernard
2016-09-26 16:55 ` Thomas Monjalon
2016-09-26 17:05 ` Wiles, Keith
2016-09-28 16:59 ` Mcnamara, John
2016-09-29 9:21 ` Mcnamara, John
2016-09-29 9:30 ` Thomas Monjalon
2016-09-29 12:08 ` Yuanhan Liu
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