DPDK patches and discussions
 help / color / mirror / Atom feed
From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.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: Wed, 21 Sep 2016 15:07:51 +0200	[thread overview]
Message-ID: <1673736.mOMazzh4h1@xps13> (raw)
In-Reply-To: <20160918082718.GF23158@yliu-dev.sh.intel.com>

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.
Opinions are welcome

  reply	other threads:[~2016-09-21 13:07 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 [this message]
2016-09-22  2:36               ` Yuanhan Liu
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

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=1673736.mOMazzh4h1@xps13 \
    --to=thomas.monjalon@6wind.com \
    --cc=ciara.loftus@intel.com \
    --cc=dev@dpdk.org \
    --cc=yuanhan.liu@linux.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).