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From: "Wiles, Keith" <keith.wiles@intel.com>
To: "Morten Brørup" <mb@smartsharesystems.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: Tue, 11 Jul 2017 16:48:10 +0000	[thread overview]
Message-ID: <D5C06081-D1D5-49DE-853C-F41B63BBE652@intel.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC359EB285@smartserver.smartshare.dk>


> 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.

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.

Regards,
Keith


  reply	other threads:[~2017-07-11 16:48 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 [this message]
2017-07-12  7:25                           ` Morten Brørup
2017-07-12  9:02                             ` Yang, Zhiyong
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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