From: "Yang, Zhiyong" <zhiyong.yang@intel.com>
To: "Morten Brørup" <mb@smartsharesystems.com>,
"Wiles, Keith" <keith.wiles@intel.com>
Cc: "Thomas Monjalon" <thomas@monjalon.net>, DPDK <dev@dpdk.org>,
"Olivier Matz" <olivier.matz@6wind.com>,
"Wang, Zhihong" <zhihong.wang@intel.com>,
"Yuanhan Liu" <yuanhan.liu@linux.intel.com>,
"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>,
"Chilikin, Andrey" <andrey.chilikin@intel.com>,
"Jan Blunck" <jblunck@infradead.org>,
"Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>,
"arybchenko@solarflare.com" <arybchenko@solarflare.com>,
"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>
Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nbsegments
Date: Wed, 12 Jul 2017 09:02:28 +0000 [thread overview]
Message-ID: <E182254E98A5DA4EB1E657AC7CB9BD2A6591FB78@BGSMSX101.gar.corp.intel.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC359EB28A@smartserver.smartshare.dk>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Morten Brørup
> Sent: Wednesday, July 12, 2017 3:25 PM
> To: Wiles, Keith <keith.wiles@intel.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; DPDK <dev@dpdk.org>; Olivier
> Matz <olivier.matz@6wind.com>; Wang, Zhihong <zhihong.wang@intel.com>;
> Yuanhan Liu <yuanhan.liu@linux.intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>; Chilikin, Andrey <andrey.chilikin@intel.com>;
> Jan Blunck <jblunck@infradead.org>; Nélio Laranjeiro
> <nelio.laranjeiro@6wind.com>; arybchenko@solarflare.com;
> jerin.jacob@caviumnetworks.com
> Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and
> nbsegments
>
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wiles, Keith
> > Sent: Tuesday, July 11, 2017 6:48 PM
> > To: Morten Brørup
> > Cc: Thomas Monjalon; DPDK; Olivier Matz; Wang, Zhihong; Yuanhan Liu;
> > Ananyev, Konstantin; Richardson, Bruce; Chilikin, Andrey; Jan Blunck;
> > Nélio Laranjeiro; arybchenko@solarflare.com;
> > jerin.jacob@caviumnetworks.com
> > Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and
> > nbsegments
> >
> >
> > > On Jul 11, 2017, at 10:23 AM, Morten Brørup
> > <mb@smartsharesystems.com> wrote:
> > >
> > >> -----Original Message-----
> > >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Thomas
> > >> Monjalon
> > >> Sent: Tuesday, July 11, 2017 5:06 PM
> > >> To: Morten Brørup
> > >> Cc: dev@dpdk.org; Wiles, Keith; Olivier Matz; Wang, Zhihong;
> > >> Yuanhan Liu; Ananyev, Konstantin; Richardson, Bruce; Chilikin,
> > >> Andrey; Jan Blunck; nelio.laranjeiro@6wind.com;
> > >> arybchenko@solarflare.com; jerin.jacob@caviumnetworks.com
> > >> Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port
> > and
> > >> nbsegments
> > >>
> > >> 11/07/2017 15:30, Morten Brørup:
> > >>> Morten Brørup wrote:
> > >>>> Olivier Matz wrote:
> > >>>>> As I said in a previous message, I think a good first step would
> > >>>>> be to introduce a typedef for the port number:
> > >> rte_eth_port_num_t.
> > >>>>> It can still be uint8_t for now, and can be switched to 16 bits
> > >> in
> > >>>>> one step when everyone uses this new type.
> > >>>>
> > >>>> I think that DPDK follows the Linux tradition of exposing the
> > >>>> variable types, as opposed to hiding them behind typedefs. This
> > has
> > >>>> the unfortunate consequence that when a variable type changes, it
> > >>>> has to be changed everywhere.
> > >>>>
> > >>>> Introducing a rte_eth_port_num_t will require changing the same
> > >>>> files at the same locations everywhere, so not even as a
> > >>>> temporary solution will it be beneficial.
> > >> [...]
> > >>> What I was trying to communicate with my long argument about type
> > >> definitions was: When the type changed from 8 bit to 16 bit, the
> > type
> > >> needs to change from uint8_t to uint16_t everywhere too, including
> > in
> > >> the ethdev APIs.
> > >>>
> > >>> Don't start breaking coding conventions here by hiding the type of
> > >> this variable.
> > >>
> > >> So, Morten, you are against the typedef, right?
> > >> Because we need to change it everywhere anyway, right?
> > >>
> > >> Note: I have no strong opinion.
> > >
> > > I'm against the typedef because it would break convention, and I'm a
> > strong proponent of conventions. In other projects, I'm all for
> > typedefs, virtual classes, inheritance etc., but DPDK follows the
> > Linux convention of not hiding simple types.
> > >
> > > We need to change it from uint8_t everywhere, regardless what we
> > > change it to. (But if we need to change it again sometime in the
> > > future, then a typedef will save us next time.)
> >
> > If the number of ports go beyond 64K then I will be the first one (if
> > still alive) to eat this email. :-) The only reason to have more then
> > 2 bytes would be to encode something into the port id value, which I
> > could see, but a very slim chance IMHO.
> >
> > >
> > > However, if we change the convention and start hiding simple types,
> > they still need the rte_ prefix regardless if they are popular or
> > obscure types. Even struct rte_mbuf has the rte_ prefix, and I
> > consider that a very popular type. If so, rte_port_t would be a good
> > name for this type.
> > >
> > > My preference: Follow convention and change it to uint16_t
> > everywhere.
> > >
> > > Med venlig hilsen / kind regards
> > > - Morten Brørup
> > >
> >
> > As we must change the uint8_t to uint16_t, then I would like it to be
> > more descriptive via a typedef. I really do not see us needing to
> > change it again in the near future. The only reason to make it a
> > typedef is to be able to identify from just the prototype of the
> > function that it takes a port ID value, which I am in favor of doing
> > here for that reason.
>
> That is not a very good reason: When used as a function parameter, the type is
> only shown in the function declaration, whereas the variable name is shown
> every time it is used inside the function. So remember to always use meaningful
> variable names, such as "port" (like in the mbuf structure) or "port_id" (used in
> other places).
>
> >
> > As for Olivier’s statement about the typedef name I do not see the
> > need for ‘_eth_' to be part of the typedef as it conveys no extra
> > information in the name. Everything port related in DPDK is a ethernet
> > type device or port. If we do add something like fiber channel maybe
> > rte_pid_t is reason to that too, but if it contains ‘_eth_’ it would
> > not.
> >
> > I would like to see names that are just short enough to convey the
> > information and not be redundant. IMHO rte_pid_t is fine, but if we
> > use some something similar to the length of uint8_t (7) or uint16_t
> > (8) characters then we would not have to also reformat the line more
> > then needed. Using rte_pid_t (pid == port_id) we only extend the
> > length by one (or two) characters and most likely the added byte(s)
> > will not cause more format problems in the code.
>
> I still don't support typedefs for scalar types. I consider it against the coding
> style, although after reviewing the official DPDK Coding Style documentation
> (http://dpdk.org/doc/guides/contributing/coding_style.html), I can see that it is
> not explicitly stated. Please also note that section 1.5.7 of the DPDK Coding
> Style documentation says that the _t postfix should be avoided. Anyway, if we
> end up with a typedef, please don't use something resembling pid_t known from
> POSIX (https://www.gnu.org/software/libc/manual/html_node/Process-
> Identification.html).
>
How about rte_dev_id_t?
Thanks
Zhiyong
>
> >
> > Regards,
> > Keith
next prev parent reply other threads:[~2017-07-12 9:02 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-24 15:19 [dpdk-dev] [RFC 0/8] mbuf: structure reorganization Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 1/8] mbuf: make segment prefree function public Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 2/8] mbuf: make raw free " Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 3/8] mbuf: set mbuf fields while in pool Olivier Matz
2017-01-24 15:50 ` Bruce Richardson
2017-02-28 14:51 ` Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 4/8] net: don't touch mbuf next or nb segs on Rx Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 5/8] mbuf: make rearm data address naturally aligned Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 6/8] mbuf: use 2 bytes for port and nb segments Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 7/8] mbuf: move sequence number in second cache line Olivier Matz
2017-01-24 15:19 ` [dpdk-dev] [RFC 8/8] mbuf: add a timestamp field Olivier Matz
2017-01-24 15:59 ` [dpdk-dev] [RFC 0/8] mbuf: structure reorganization Bruce Richardson
2017-01-24 16:16 ` Olivier MATZ
2017-02-06 18:41 ` Ananyev, Konstantin
2017-02-09 16:20 ` Morten Brørup
2017-02-09 16:56 ` Ananyev, Konstantin
2017-02-16 13:48 ` Olivier Matz
2017-02-16 15:46 ` Bruce Richardson
2017-02-16 16:14 ` Olivier Matz
2017-02-21 14:20 ` Morten Brørup
2017-02-21 14:28 ` Bruce Richardson
2017-02-21 15:04 ` Olivier MATZ
2017-02-21 15:18 ` Bruce Richardson
2017-02-21 15:18 ` Morten Brørup
2017-02-19 19:04 ` Chilikin, Andrey
2017-02-21 9:53 ` Olivier MATZ
2017-02-16 17:26 ` Jan Blunck
2017-02-17 10:51 ` Olivier Matz
2017-02-17 12:49 ` Nélio Laranjeiro
2017-02-17 13:51 ` Jan Blunck
2017-02-18 5:48 ` Andrew Rybchenko
2017-02-17 13:38 ` Jan Blunck
2017-02-17 14:17 ` Olivier Matz
2017-02-17 18:42 ` Ananyev, Konstantin
2017-02-21 9:53 ` Olivier MATZ
2017-02-21 10:28 ` Ananyev, Konstantin
2017-02-20 9:27 ` Jan Blunck
2017-02-21 9:54 ` Olivier MATZ
2017-02-21 16:12 ` Jan Blunck
2017-02-21 16:38 ` Bruce Richardson
2017-02-21 17:04 ` Jan Blunck
2017-02-21 17:26 ` Ananyev, Konstantin
2017-02-21 19:17 ` Jan Blunck
2017-02-21 20:30 ` Ananyev, Konstantin
2017-02-21 21:51 ` Morten Brørup
2017-02-24 14:11 ` Olivier Matz
2017-02-24 14:00 ` Olivier Matz
2017-02-24 14:21 ` Bruce Richardson
2017-02-28 8:55 ` Jan Blunck
2017-02-28 9:05 ` Ananyev, Konstantin
2017-02-28 9:23 ` Olivier Matz
2017-02-28 9:33 ` Jan Blunck
2017-02-28 10:29 ` Ananyev, Konstantin
2017-02-28 10:50 ` Olivier Matz
2017-02-28 11:48 ` Ananyev, Konstantin
2017-02-28 12:28 ` Olivier Matz
2017-02-28 22:53 ` Ananyev, Konstantin
2017-03-02 16:46 ` Olivier Matz
2017-03-08 11:11 ` Ananyev, Konstantin
2017-03-20 9:00 ` Olivier Matz
2017-03-22 17:42 ` Ananyev, Konstantin
2017-03-24 8:35 ` Jerin Jacob
2017-03-24 13:35 ` Olivier Matz
2017-02-28 9:25 ` Jan Blunck
2017-02-19 23:45 ` Ananyev, Konstantin
2017-02-21 9:22 ` Morten Brørup
2017-02-21 9:54 ` Olivier MATZ
2017-03-08 9:41 ` [dpdk-dev] [PATCH 0/9] " Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 1/9] mbuf: make segment prefree function public Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 2/9] mbuf: make raw free " Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 3/9] mbuf: set mbuf fields while in pool Olivier Matz
2017-03-31 11:21 ` Bruce Richardson
2017-03-31 11:51 ` Ananyev, Konstantin
2017-03-08 9:41 ` [dpdk-dev] [PATCH 4/9] drivers/net: don't touch mbuf next or nb segs on Rx Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 5/9] mbuf: make rearm data address naturally aligned Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 6/9] mbuf: use 2 bytes for port and nb segments Olivier Matz
2017-03-08 9:41 ` [dpdk-dev] [PATCH 7/9] mbuf: move sequence number in second cache line Olivier Matz
2017-03-08 9:42 ` [dpdk-dev] [PATCH 8/9] mbuf: add a timestamp field Olivier Matz
2017-04-04 10:29 ` [dpdk-dev] [PATCH 0/2] reduce writes to mbuf in ixgbe vRX Konstantin Ananyev
2017-04-07 15:13 ` Ferruh Yigit
2017-04-07 15:44 ` Ferruh Yigit
2017-04-09 22:56 ` Ananyev, Konstantin
2017-04-04 10:29 ` [dpdk-dev] [PATCH 1/2] net/ixgbe: eliminate mbuf write on rearm Konstantin Ananyev
2017-04-10 15:59 ` [dpdk-dev] [PATCH v2 0/2] reduce writes to mbuf in ixgbe vRX Konstantin Ananyev
2017-04-10 16:17 ` Ferruh Yigit
2017-04-10 15:59 ` [dpdk-dev] [PATCH v2 1/2] net/ixgbe: eliminate mbuf write on rearm Konstantin Ananyev
2017-04-10 15:59 ` [dpdk-dev] [PATCH v2 2/2] net/ixgbe: remove option to disable offload flags Konstantin Ananyev
2017-04-04 10:29 ` [dpdk-dev] [PATCH " Konstantin Ananyev
2017-03-08 9:42 ` [dpdk-dev] [PATCH 9/9] mbuf: reorder VLAN tci and buffer len fields Olivier Matz
2017-03-29 15:56 ` [dpdk-dev] [PATCH 0/9] mbuf: structure reorganization Olivier Matz
2017-03-29 16:03 ` Morten Brørup
2017-03-29 20:09 ` Bruce Richardson
2017-03-30 9:31 ` Bruce Richardson
2017-03-30 12:02 ` Olivier Matz
2017-03-30 12:23 ` Bruce Richardson
2017-03-30 16:45 ` Ananyev, Konstantin
2017-03-30 16:47 ` Ananyev, Konstantin
2017-03-30 18:06 ` Ananyev, Konstantin
2017-03-31 8:41 ` Olivier Matz
2017-03-31 9:58 ` Ananyev, Konstantin
2017-03-31 1:00 ` Ananyev, Konstantin
2017-03-31 7:21 ` Morten Brørup
2017-03-31 8:26 ` Olivier Matz
2017-03-31 8:41 ` Bruce Richardson
2017-03-31 8:59 ` Olivier Matz
2017-03-31 9:18 ` Ananyev, Konstantin
2017-03-31 9:36 ` Olivier Matz
2017-04-03 16:15 ` Thomas Monjalon
2017-04-04 7:58 ` Olivier MATZ
2017-04-04 8:53 ` Bruce Richardson
2017-03-31 9:23 ` Bruce Richardson
2017-03-31 11:18 ` Nélio Laranjeiro
2017-03-30 14:54 ` Andrew Rybchenko
2017-03-30 15:12 ` Jerin Jacob
2017-04-04 16:27 ` [dpdk-dev] [PATCH v2 0/8] " Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 1/8] mbuf: make segment prefree function public Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 2/8] mbuf: make raw free " Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 3/8] mbuf: set mbuf fields while in pool Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 4/8] drivers/net: don't touch mbuf next or nb segs on Rx Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 5/8] mbuf: make rearm data address naturally aligned Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nb segments Olivier Matz
2017-04-06 5:45 ` Yuanhan Liu
2017-04-18 13:03 ` Olivier MATZ
2017-07-04 7:54 ` Wang, Zhihong
2017-07-10 8:00 ` Olivier Matz
2017-07-10 8:15 ` Morten Brørup
2017-07-11 13:25 ` Wiles, Keith
2017-07-11 13:30 ` Morten Brørup
2017-07-11 15:05 ` Thomas Monjalon
2017-07-11 15:23 ` [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nbsegments Morten Brørup
2017-07-11 16:48 ` Wiles, Keith
2017-07-12 7:25 ` Morten Brørup
2017-07-12 9:02 ` Yang, Zhiyong [this message]
2017-07-12 9:50 ` [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port andnbsegments Morten Brørup
2017-07-12 15:35 ` Stephen Hemminger
2017-07-12 15:57 ` Morten Brørup
2017-07-12 16:23 ` Thomas Monjalon
2017-07-12 18:20 ` Wiles, Keith
2017-07-21 15:03 ` Bruce Richardson
2017-07-12 15:34 ` [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nbsegments Wiles, Keith
2017-07-11 13:34 ` [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nb segments Wiles, Keith
2017-07-11 13:46 ` Olivier MATZ
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 7/8] mbuf: move sequence number in second cache line Olivier Matz
2017-04-04 16:28 ` [dpdk-dev] [PATCH v2 8/8] mbuf: add a timestamp field Olivier Matz
2017-04-05 9:37 ` [dpdk-dev] [PATCH v2 0/8] mbuf: structure reorganization Thomas Monjalon
2017-04-05 9:46 ` Olivier MATZ
2017-04-05 9:48 ` Richardson, Bruce
2017-04-05 12:06 ` Ferruh Yigit
2017-04-14 13:10 ` Ferruh Yigit
2017-04-18 13:04 ` Olivier MATZ
2017-04-19 9:39 ` Thomas Monjalon
2017-04-19 12:28 ` Olivier MATZ
2017-04-19 12:56 ` Thomas Monjalon
2017-04-19 13:03 ` Ferruh Yigit
2017-04-19 13:12 ` Thomas Monjalon
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