From: "Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
Olivier Matz <olivier.matz@6wind.com>,
"Lu, Wenzhuo" <wenzhuo.lu@intel.com>,
Adrien Mazarguil <adrien.mazarguil@6wind.com>
Subject: Re: [dpdk-dev] [PATCH] net: introduce big and little endian types
Date: Tue, 6 Dec 2016 14:14:17 +0100 [thread overview]
Message-ID: <20161206131416.GR21794@autoinstall.dev.6wind.com> (raw)
In-Reply-To: <20161206115502.GA12224@bricha3-MOBL3.ger.corp.intel.com>
Hi Konstantin, Bruce,
On Tue, Dec 06, 2016 at 11:55:02AM +0000, Bruce Richardson wrote:
> On Tue, Dec 06, 2016 at 11:23:42AM +0000, Ananyev, Konstantin wrote:
> > Hi Neilo,
> >
> >
> > Hi Neilo,
> > > > >
> > > > > This commit introduces new rte_{le,be}{16,32,64}_t types and updates
> > > > > rte_{le,be,cpu}_to_{le,be,cpu}_*() and network header structures
> > > > > accordingly.
> > > > >
> > > > > Specific big/little endian types avoid uncertainty and conversion mistakes.
> > > > >
> > > > > No ABI change since these are simply typedefs to the original types.
> > > >
> > > > It seems like quite a lot of changes...
> > > > Could you probably explain what will be the benefit in return?
> > > > Konstantin
> > >
> > > Hi Konstantin,
> > >
> > > The benefit is to provide documented byte ordering for data types
> > > software is manipulating to determine when network to CPU (or CPU to
> > > network) conversion must be performed.
> >
> > Ok, but is it really worth it?
> > User can still make a mistake and forget to call ntoh()/hton() at some particular place.
> > From other side most people do know that network protocols headers are usually in BE format.
> > I would understand the effort, if we'll have some sort of tool that would do some sort of static code analysis
> > based on these special types or so.
> > Again, does it mean that we should go and change uint32_t to rte_le_32 inside all Intel PMDs
> > (and might be in some others too) to be consistent?
> > Konstantin
> >
>
> I actually quite like this patch as I think it will help make things
> clear when the user is possibly doing something wrong. I don't think we
> need to globally change all PMDs to use the types, though.
I agree, at least APIs should use this, PMDs can do as they want.
> One thing I'm wondering though, is if we might want to take this
> further. For little endian environments, we could define the big endian
> types as structs using typedefs, and similarly the le types on be
> platforms, so that assigning from the non-native type to the native one
> without a transformation function would cause a compiler error.
>
> /Bruce
If I understand you correctly, this will break hton like functions which
expects an uint*_t not a structure.
--
Nélio Laranjeiro
6WIND
next prev parent reply other threads:[~2016-12-06 13:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-09 15:04 Nelio Laranjeiro
2016-12-05 10:09 ` Ananyev, Konstantin
2016-12-05 12:06 ` Nélio Laranjeiro
2016-12-06 11:23 ` Ananyev, Konstantin
2016-12-06 11:55 ` Bruce Richardson
2016-12-06 12:41 ` Ananyev, Konstantin
2016-12-06 13:34 ` Bruce Richardson
2016-12-06 14:45 ` Ananyev, Konstantin
2016-12-06 14:56 ` Wiles, Keith
2016-12-06 15:34 ` Morten Brørup
2016-12-06 16:28 ` Nélio Laranjeiro
2016-12-06 16:31 ` Wiles, Keith
2016-12-06 16:36 ` Richardson, Bruce
2016-12-06 17:00 ` Ananyev, Konstantin
2016-12-06 17:29 ` Neil Horman
2016-12-06 13:14 ` Nélio Laranjeiro [this message]
2016-12-06 13:30 ` Bruce Richardson
2016-12-06 14:06 ` Wiles, Keith
2016-12-08 9:30 ` Nélio Laranjeiro
2016-12-08 13:59 ` Wiles, Keith
2016-12-08 16:06 ` Thomas Monjalon
2016-12-08 15:07 ` Neil Horman
2016-12-08 15:10 ` Ananyev, Konstantin
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