From: "Lu, Wenzhuo" <wenzhuo.lu@intel.com>
To: Thomas Monjalon <thomas@monjalon.net>,
Andrew Rybchenko <arybchenko@solarflare.com>,
"Yigit, Ferruh" <ferruh.yigit@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v2] ethdev: fix device info getting
Date: Mon, 13 Aug 2018 02:50:05 +0000 [thread overview]
Message-ID: <6A0DE07E22DDAD4C9103DF62FEBC09093B81A090@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <1716659.kXphz3AMnz@xps>
Hi Thomas,
> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Wednesday, August 1, 2018 11:37 PM
> To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Andrew Rybchenko
> <arybchenko@solarflare.com>; Yigit, Ferruh <ferruh.yigit@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] ethdev: fix device info getting
>
> 16/07/2018 03:58, Lu, Wenzhuo:
> > Hi Andrew,
> >
> > > -----Original Message-----
> > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Lu, Wenzhuo
> > > Sent: Monday, July 16, 2018 9:08 AM
> > > To: Andrew Rybchenko <arybchenko@solarflare.com>; dev@dpdk.org
> > > Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Thomas Monjalon
> > > <thomas@monjalon.net>
> > > Subject: Re: [dpdk-dev] [PATCH v2] ethdev: fix device info getting
> > >
> > > Hi Andrew,
> > >
> > > > -----Original Message-----
> > > > From: Andrew Rybchenko [mailto:arybchenko@solarflare.com]
> > > > Sent: Friday, July 13, 2018 4:03 PM
> > > > To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; dev@dpdk.org
> > > > Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Thomas Monjalon
> > > > <thomas@monjalon.net>
> > > > Subject: Re: [dpdk-dev] [PATCH v2] ethdev: fix device info getting
> > > >
> > > > Hi, Wenzhuo,
> > > >
> > > > I'm sorry, but I have more even harder questions than the previous one.
> > > > This questions are rather generic and mainly to ethdev maintainers.
> > > >
> > > > On 13.07.2018 05:42, Wenzhuo Lu wrote:
> > > > > The device information cannot be gotten correctly before the
> > > > > configuration is set. Because on some NICs the information has
> > > > > dependence on the configuration.
> > > >
> > > > Thinking about it I have the following question. Is it valid
> > > > behaviour of the dev_info if it changes after configuration?
> > > > I always thought that the primary goal of the dev_info is to
> > > > provide information to app about device capabilities to allow app
> > > > configure device and queues correctly. Now we see the case when
> > > > dev_info changes on configure. May be it is acceptable, but it is
> > > > really suspicious. If we accept it, it should be documented.
> > > > May be dev_info should be split into parts: part which is
> > > > persistent and part which may depend on device configuration.
> > > As I remember, the similar discussion has happened :) I've raised
> > > the similar suggestion like this. But we don’t make it happen.
> > > The reason is, you see, this is the rte layer's behavior. So the
> > > user doesn't have to know it. From APP's PoV, it inputs the
> > > configuration, it calls this API "rte_eth_dev_configure". It doesn't
> > > know the configuration is copied before getting the info or not.
> > > So, to my opinion, we can still keep the behavior. We only need to
> > > split it into parts when we do see the case that cannot make it.
> > Maybe I talked too much about the patch. Think about it again. Your
> > comments is about how to use the APIs, rte_eth_dev_info_get,
> rte_eth_dev_configure. To my opinion, rte_eth_dev_info_get is just to get
> the info. It can be called anywhere, before configuration or after. It's
> reasonable the info changes with the configuration changing.
> > But we do have something missing, like, rte_eth_dev_capability_get which
> should be stable. APP can use this API to get the necessary info before
> configuration.
> >
> > A question, maybe a little divergent thinking, that APP should have some
> intelligence to handle the capability automatically. So getting the capability
> is not so good and effective, looks like we still need the human involvement.
> Maybe that the reason currently we suppose APP know the capability from
> the paper copies, examples...
>
> I am not sure to understand all the sentences.
> But I agree that we should take a decision about the stability of these infos.
> Either infos cannot change after probing, or we must document that the app
> must request infos regularly (when?).
Sorry, I missed this mail.
I have the concern that different NICs have different behavior. One info can be stable on a NIC but dynamic on another. Considering this, we may better not splitting the rte_eth_dev_info_get to 2 APIs. And comparing with handling this in rte layer, maybe we can let every NIC has its own decision.
I have an idea. Maybe we can add a parameter for potential dynamic fields. Like,
Changing
uint16_t nb_rx_queues;
to
struct nb_rx_queues {
uint16_t value;
bool stable;
}
By default, the stable is false. Then every NIC can maintain its own behavior.
Some fileds that must be stable can be left unchanged, like, driver_name, max_rx_queues.
As this patch is just reversing a bad commit to fix a bug, if my idea sounds good or worth discussing, I can send another RFC mail for it.
next prev parent reply other threads:[~2018-08-13 2:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-12 5:27 [dpdk-dev] [PATCH] " Wenzhuo Lu
2018-07-12 8:06 ` Andrew Rybchenko
2018-07-13 1:56 ` Lu, Wenzhuo
2018-07-13 2:42 ` [dpdk-dev] [PATCH v2] " Wenzhuo Lu
2018-07-13 8:02 ` Andrew Rybchenko
2018-07-16 1:08 ` Lu, Wenzhuo
2018-07-16 1:58 ` Lu, Wenzhuo
2018-08-01 15:36 ` Thomas Monjalon
2018-08-13 2:50 ` Lu, Wenzhuo [this message]
2018-08-13 8:38 ` Andrew Rybchenko
2018-08-14 0:57 ` Lu, Wenzhuo
2018-08-22 16:55 ` Ferruh Yigit
2018-08-23 8:58 ` Andrew Rybchenko
2018-10-22 12:01 ` Ferruh Yigit
2018-10-22 12:13 ` Thomas Monjalon
2018-10-23 1:25 ` Lu, Wenzhuo
2018-10-23 7:28 ` Thomas Monjalon
2018-11-06 0:56 ` Lu, Wenzhuo
2018-11-06 7:40 ` Andrew Rybchenko
2018-11-08 2:09 ` [dpdk-dev] [PATCH v3 1/2] " Wenzhuo Lu
2018-11-08 2:09 ` [dpdk-dev] [PATCH v3 2/2] ethdev: device configuration enhancement Wenzhuo Lu
2018-11-08 6:25 ` Andrew Rybchenko
2018-11-09 21:10 ` Ferruh Yigit
2018-11-13 0:46 ` Lu, Wenzhuo
2018-11-13 9:40 ` Ferruh Yigit
2018-11-14 1:28 ` Lu, Wenzhuo
2018-11-13 11:12 ` [dpdk-dev] [PATCH v4 1/3] ethdev: fix invalid device configuration after failure Ferruh Yigit
2018-11-13 11:12 ` [dpdk-dev] [PATCH v4 2/3] ethdev: fix device info getting Ferruh Yigit
2018-11-13 11:19 ` Andrew Rybchenko
2018-11-13 11:12 ` [dpdk-dev] [PATCH v4 3/3] ethdev: eliminate interim variable Ferruh Yigit
2018-11-13 11:22 ` Andrew Rybchenko
2018-11-13 11:51 ` Ferruh Yigit
2018-11-13 11:56 ` Andrew Rybchenko
2018-11-13 11:19 ` [dpdk-dev] [PATCH v4 1/3] ethdev: fix invalid device configuration after failure Andrew Rybchenko
2018-11-13 17:49 ` Ferruh Yigit
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=6A0DE07E22DDAD4C9103DF62FEBC09093B81A090@shsmsx102.ccr.corp.intel.com \
--to=wenzhuo.lu@intel.com \
--cc=arybchenko@solarflare.com \
--cc=dev@dpdk.org \
--cc=ferruh.yigit@intel.com \
--cc=thomas@monjalon.net \
/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).