From: "Gaëtan Rivet" <gaetan.rivet@6wind.com>
To: Jan Blunck <jblunck@infradead.org>
Cc: Thomas Monjalon <thomas@monjalon.net>, dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v5 5/7] bus: add helper to find a bus from a device name
Date: Thu, 29 Jun 2017 12:23:53 +0200 [thread overview]
Message-ID: <20170629102353.GK13355@bidouze.vm.6wind.com> (raw)
In-Reply-To: <CALe+Z03YBc=n+QXP3O4oUunENi30RLdKK4-3BSaDNTpi0YmYAw@mail.gmail.com>
On Thu, Jun 29, 2017 at 09:56:30AM +0200, Jan Blunck wrote:
> On Wed, Jun 28, 2017 at 7:03 PM, Thomas Monjalon <thomas@monjalon.net> wrote:
> > 27/06/2017 20:55, Jan Blunck:
> >> On Wed, Jun 21, 2017 at 1:30 AM, Gaetan Rivet <gaetan.rivet@6wind.com> wrote:
> >> > /**
> >> > + * Find a bus capable of identifying a device.
> >> > + *
> >> > + * @param str
> >> > + * A device identifier (PCI address, virtual PMD name, ...).
> >> > + *
> >> > + * @return
> >> > + * A valid bus handle if found.
> >> > + * NULL if no bus is able to parse this device.
> >> > + */
> >> > +struct rte_bus *rte_bus_from_dev(const char *str);
> >>
> >> I still don't agree with this. The bus name should be passed
> >> explicitly by the user of the API.
> >>
> >> NAK.
> >
> > Please explain why you think the bus name should be explicit.
> > If the bus is ambiguous, it can be explicited by the user.
> >
> > I see some good benefits in being tolerant with the bus/device
> > representation. It provides a smooth transition to the bus model.
> >
>
> We build libraries. The applications we build with the help of those
> libraries get notified by the OS about device events. Those devices
> are chields of their parent bus. At the time the event is fired the OS
> already knows about:
>
> - the bus name (parent)
> - the device name (child)
> - additional event parameters (environment)
>
> Blame me that I probably spent too much time with Kay Sievers and
> GregKH to understand that device naming is easy to get wrong. Just
> look at the hyperv device names and how they switched to the UUID
> scheme. I don't think that hyperv is the only bus that uses UUID as
> device identification. We should not codify a policy of how to deduce
> a bus name from a given device name if that is knowledge that is
> already present externally. Otherwise I fear this part of the EAL will
> be subject to constant churn.
I agree in the context of device events.
But this development concerns all device identification scheme, not only
in the context of hotplug where we can retrieve events giving proper
info. It is parsing user input as well (command line or configuration).
In this user-centric device specification, the issue is that the current
model expect the user to provide the bus implicitly by using the right
parameter (--vdev, -w). This identification *cannot* stay, as those are
parsed within the EAL and specifics are getting out.
What is left is thus a choice: either
* We let the current scheme work for a time, while the EAL is being cleaned
out, during which we need some crutch to emulate the current behavior
* We force all users to migrate to the new format straight away with a
full identification scheme.
I planned for both eventuality in my deprecation notice, by warning that
device parameters and definition might change this version. However,
while I thought that it was possible it would happen, I think it is best
to provide as much stability as possible while we work out the EAL
internals.
This API is only there because I choose to keep backward compatibility.
A compromise might be to make it private to the EAL (I proposed it
before but no one really responded so I haven't acted on it). This would
help the future transition to the fully-qualified-device-identifier that
we will have to require from our users.
I'd like to hear from other DPDK devs as I think that surprising users
is not something that should be done lightly. I understand your concern
and am not opposed to address it.
--
Gaëtan Rivet
6WIND
next prev parent reply other threads:[~2017-06-29 10:24 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-24 15:12 [dpdk-dev] [PATCH 0/9] rte_bus parse API Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 1/9] bus: fix bus name registration Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 2/9] bus: verify bus name on registration Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 3/9] bus: introduce parsing functionality Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 4/9] vdev: implement parse bus operation Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 5/9] pci: " Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 6/9] bus: add helper to find bus from a name Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 7/9] bus: add helper to find a bus from a device name Gaetan Rivet
2017-06-07 17:28 ` Jan Blunck
2017-06-07 20:03 ` Gaëtan Rivet
2017-06-08 10:45 ` Jan Blunck
2017-06-08 11:36 ` Gaëtan Rivet
2017-06-08 11:40 ` Jan Blunck
2017-06-08 12:51 ` Gaëtan Rivet
2017-06-10 8:50 ` Jan Blunck
2017-06-12 14:21 ` Gaëtan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 8/9] vdev: expose bus name Gaetan Rivet
2017-05-24 15:12 ` [dpdk-dev] [PATCH 9/9] devargs: parse bus info Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 0/9] rte_bus parse API Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 1/9] bus: fix bus name registration Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 2/9] bus: verify bus name on registration Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 3/9] bus: introduce parsing functionality Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 4/9] vdev: implement parse bus operation Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 5/9] pci: " Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 6/9] bus: add helper to find bus from a name Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 7/9] bus: add helper to find a bus from a device name Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 8/9] vdev: expose bus name Gaetan Rivet
2017-05-24 16:15 ` [dpdk-dev] [PATCH v2 9/9] devargs: parse bus info Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 0/9] rte_bus parse API Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 1/9] bus: fix bus name registration Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 2/9] bus: verify bus name on registration Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 3/9] bus: introduce parsing functionality Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 4/9] vdev: implement parse bus operation Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 5/9] pci: " Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 6/9] bus: add helper to find bus from a name Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 7/9] bus: add helper to find a bus from a device name Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 8/9] vdev: expose bus name Gaetan Rivet
2017-06-01 10:08 ` [dpdk-dev] [PATCH v3 9/9] devargs: parse bus info Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 0/9] rte_bus parse API Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 1/9] bus: fix bus name registration Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 2/9] bus: verify bus name on registration Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 3/9] bus: introduce parsing functionality Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 4/9] vdev: implement parse bus operation Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 5/9] pci: " Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 6/9] bus: add helper to find a bus from a bus name Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 7/9] bus: add helper to find a bus from a device name Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 8/9] vdev: expose bus name Gaetan Rivet
2017-06-07 23:56 ` [dpdk-dev] [PATCH v4 9/9] devargs: parse bus info Gaetan Rivet
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 0/7] rte_bus parse API Gaetan Rivet
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 1/7] bus: fix bus name registration Gaetan Rivet
2017-06-27 15:53 ` Bruce Richardson
2017-06-27 19:19 ` Jan Blunck
2017-07-04 1:05 ` Gaëtan Rivet
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 2/7] bus: introduce parsing functionality Gaetan Rivet
2017-06-27 15:54 ` Bruce Richardson
2017-06-27 19:26 ` Jan Blunck
2017-07-04 1:35 ` Gaëtan Rivet
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 3/7] vdev: implement parse bus operation Gaetan Rivet
2017-06-27 15:59 ` Bruce Richardson
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 4/7] pci: " Gaetan Rivet
2017-06-27 16:18 ` Bruce Richardson
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 5/7] bus: add helper to find a bus from a device name Gaetan Rivet
2017-06-27 16:26 ` Bruce Richardson
2017-06-27 18:55 ` Jan Blunck
2017-06-28 17:03 ` Thomas Monjalon
2017-06-29 7:56 ` Jan Blunck
2017-06-29 8:21 ` Thomas Monjalon
2017-06-29 10:23 ` Gaëtan Rivet [this message]
2017-06-29 10:30 ` Richardson, Bruce
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 6/7] vdev: expose bus name Gaetan Rivet
2017-06-20 23:30 ` [dpdk-dev] [PATCH v5 7/7] devargs: parse bus info Gaetan Rivet
2017-06-27 16:01 ` [dpdk-dev] [PATCH v5 0/7] rte_bus parse API Bruce Richardson
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 0/6] " Gaetan Rivet
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 1/6] bus: fix bus name registration Gaetan Rivet
2017-07-04 21:43 ` [dpdk-dev] [PATCH] bus: fix driver registration Thomas Monjalon
2017-07-05 5:47 ` Shreyansh Jain
2017-07-05 6:01 ` Shreyansh Jain
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 2/6] bus: introduce parsing functionality Gaetan Rivet
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 3/6] vdev: implement parse bus operation Gaetan Rivet
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 4/6] pci: " Gaetan Rivet
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 5/6] bus: add helper to find a bus from a device name Gaetan Rivet
2017-07-04 12:28 ` Gaëtan Rivet
2017-07-04 0:58 ` [dpdk-dev] [PATCH v6 6/6] devargs: parse bus info Gaetan Rivet
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 0/6] rte_bus parse API Gaetan Rivet
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 1/6] bus: fix driver registration Gaetan Rivet
2017-07-05 13:03 ` Shreyansh Jain
2017-07-06 6:05 ` santosh
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 2/6] bus: introduce parsing functionality Gaetan Rivet
2017-07-05 13:04 ` Shreyansh Jain
2017-07-06 9:19 ` santosh
2017-07-06 12:30 ` Gaëtan Rivet
2017-07-06 13:12 ` santosh
2017-07-06 13:30 ` Gaëtan Rivet
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 3/6] vdev: implement parse bus operation Gaetan Rivet
2017-07-05 13:16 ` Shreyansh Jain
2017-07-06 9:35 ` santosh
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 4/6] pci: " Gaetan Rivet
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 5/6] bus: add helper to find a bus from a device name Gaetan Rivet
2017-07-05 13:35 ` Shreyansh Jain
2017-07-05 13:45 ` Gaëtan Rivet
2017-07-05 14:12 ` Shreyansh Jain
2017-07-06 10:10 ` Thomas Monjalon
2017-07-06 11:37 ` Gaëtan Rivet
2017-07-04 23:55 ` [dpdk-dev] [PATCH v7 6/6] devargs: parse bus info Gaetan Rivet
2017-07-05 18:03 ` Stephen Hemminger
2017-07-06 9:07 ` Shreyansh Jain
2017-07-06 10:00 ` Gaëtan Rivet
2017-07-06 13:17 ` Shreyansh Jain
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 0/6] rte_bus parse API Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 1/6] bus: fix driver registration Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 2/6] bus: introduce parsing functionality Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 3/6] vdev: implement parse bus operation Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 4/6] pci: " Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 5/6] bus: add helper to find a bus from a device name Gaetan Rivet
2017-07-07 0:03 ` [dpdk-dev] [PATCH v8 6/6] devargs: parse bus info Gaetan Rivet
2017-07-07 0:45 ` Stephen Hemminger
2017-07-07 8:31 ` Gaëtan Rivet
2017-07-08 20:31 ` Thomas Monjalon
2017-07-08 20:30 ` [dpdk-dev] [PATCH v8 0/6] rte_bus parse API Thomas Monjalon
2017-06-07 17:22 ` [dpdk-dev] [PATCH 0/9] " Jan Blunck
2017-06-07 19:55 ` Gaëtan Rivet
2017-06-08 11:38 ` Jan Blunck
2017-06-08 13:04 ` Gaëtan Rivet
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