Re: [dpdk-dev] [PATCH 0/5] remove usage of register keyword in C

[Yongseok Koh <yskoh@mellanox.com>]

> On Jul 31, 2018, at 11:07 AM, Stephen Hemminger <stephen@networkplumber.org> wrote:
> 
> On Tue, 31 Jul 2018 18:48:40 +0200
> Adrien Mazarguil <adrien.mazarguil@6wind.com> wrote:
> 
>> On Tue, Jul 31, 2018 at 09:30:54AM -0700, Stephen Hemminger wrote:
>>> Declaring variables as register in C is a leftover from an earlier
>>> era (like cassette tape decks in cars).  
>> 
>> I don't agree here. It's a hint for compilers and developers that the
>> address of such variables won't be needed (and cannot be taken) to enable
>> whatever optimizations are possible knowing this.
>> 
>> Somewhat like inline functions, it's not a forced optimization, just a
>> useful hint that shouldn't hurt if used wisely.
>> 
>> Besides, cassette decks are not dead yet :)
> 
> If you look at the code, that is not how register is being used (ie. don't take
> address of this). It seems like an attempt at optimization.

I know compilers are smart enough and the occurrences in mlx4/5 were made from
my old fashioned habit. But, I don't see any urgency to push this patch in RC
stage even though I'm 99% sure that it is harmless. And in general I don't even
understand why we can't live with that if it isn't harmful (or a violation) but
informative. I mean no badness but at least one goodness :-)

Thanks,
Yongseok