[dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and nb segments

[Wiles, Keith]

On Jul 10, 2017, at 3:15 AM, Morten Brørup <mb at smartsharesystems.com<mailto:mb at smartsharesystems.com>> wrote:

-----Original Message-----
From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier Matz
Sent: Monday, July 10, 2017 10:00 AM
Subject: Re: [dpdk-dev] [PATCH v2 6/8] mbuf: use 2 bytes for port and
nb segments

Hi,

On Tue, 4 Jul 2017 07:54:23 +0000, "Wang, Zhihong"
<zhihong.wang at intel.com<mailto:zhihong.wang at intel.com>> wrote:
-----Original Message-----
From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Olivier MATZ
Sent: Tuesday, April 18, 2017 9:03 PM
To: Yuanhan Liu <yuanhan.liu at linux.intel.com<mailto:yuanhan.liu at linux.intel.com>>

Hi Yuanhan,

On Thu, 6 Apr 2017 13:45:23 +0800, Yuanhan Liu
<yuanhan.liu at linux.intel.com<mailto:yuanhan.liu at linux.intel.com>> wrote:
Hi Olivier,

On Tue, Apr 04, 2017 at 06:28:05PM +0200, Olivier Matz wrote:
Change the size of m->port and m->nb_segs to 16 bits.

But all the ethdev APIs are still using 8 bits. 16 bits won't
really take effect without updating those APIs. Any plans?

--yliu

Yes, there is some work in ethdev, drivers and in example apps to
make the change effective. I think we could define a specific type
for a port number, maybe rte_eth_port_num_t. Using this type could
be a first step (for 17.08) before switching to 16 bits (17.11?).

I'll do the change and send a rfc.

Ping ;) Is this still in your plan?


Sorry, I don't think I will have time to work on this issue in the
coming weeks. If you plan to do it, I will be happy to help with
reviews and comments.

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.

Olivier

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.

I would like to see a much smaller typedef name here, we use it everywhere.
rte_port_id_t
port_id_t
port_num_t
portid_t

I do not see why it needs to be rte_eth or even rte_, if we do not put eth in the name then is could be used in crypto or someplace else.




Med venlig hilsen / kind regards
- Morten Brørup

Regards,
Keith