Re: [dpdk-dev] [PATCH v2] doc: add preferred burst size support

[Shreyansh Jain <shreyansh.jain@nxp.com>]

Hi Bruce,

On Thursday 01 February 2018 07:49 PM, Bruce Richardson wrote:
> On Thu, Feb 01, 2018 at 07:58:32PM +0530, Shreyansh Jain wrote:
>> On Thursday 01 February 2018 06:57 PM, Bruce Richardson wrote:
>>> On Thu, Feb 01, 2018 at 06:18:23PM +0530, Shreyansh Jain wrote:
>>>> rte_eth_rx_burst(..,nb_pkts) function has semantic that if return value
>>>> is smaller than requested, application can consider it end of packet
>>>> stream. Some hardware can only support smaller burst sizes which need
>>>> to be advertised. Similar is the case for Tx burst.
>>>>
>>>> This patch adds deprecation notice for rte_eth_dev_info structure as
>>>> two new members, for preferred Rx and Tx burst size would be added -
>>>> impacting the size of the structure.
>>>>
>>>> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
>>>> ---

[...]

>>>
>>> LTGM as far as it goes, but following discussion on this patch,
>>> http://dpdk.org/ml/archives/dev/2018-January/089585.html
>>> I think we might also want to add in parameters for "pref_tx_ring_sz"
>>> and "pref_rx_ring_sz" too. While it is the case that, once the structure
>>> is changed, we can make multiple additional changes, I think it might be
>>> worth mentioning as many as we can for completeness.
>>>
>>> Another point to consider, is whether we might want to add in a
>>> sub-structure for "preferred_settings" to hold all these, rather than
>>> just adding them as new fields. It might help with making names more
>>> readable (though also longer).
>>>
>>> 	struct {
>>> 		uint16_t rx_burst;
>>> 		uint16_t tx_burst;
>>> 		uint16_t rx_ring_sz;
>>> 		uint16_t tx_ring_sz;
>>> 	} preferred_settings;
>>
>> This, and the point above that we can make multiple additional changes, is
>> definitely a good idea. Though, 'preferred_setting' is long and has chances
>> of spell mistakes in first go - what about just 'pref' or, 'pref_size' if
>> only 4 mentioned above are part of this.
>>
>> For now I saw need for burst size because I hit that case. Ring size looks
>> logical to me. We can have a look if more such toggles are required.
>>
> 
> I actually don't like the abbreviation "pref", as it looks too much like
> "perf" short for performance. As this is an initialization setting, I
> also don't think having a longer name is that big of deal. How about
> calling them "suggested" or "recommended" settings - both of which have
> less fiddly spellings.
> 
> /Bruce
> 

I get your point and on a second thought even I think 'preferred_*' is 
better than other options (including mine). Only change I will do is 
change to 'preferred_size' as all members are size only:

         struct {
                 uint16_t rx_burst; /*< Rx Burst size */
                 uint16_t tx_burst; /*< Tx Burst size */
                 uint16_t rx_ring;  /*< Rx ring size */
                 uint16_t tx_ring;  /*< Tx ring size */
         } preferred_size;

I will use your ACK but if you have objections to focusing on size only 
in this structure - let me know. I will send across another patch and 
put it as 'preferred_settings' and then we can discuss the naming during 
implementation.

-
Shreyansh