Re: [PATCH] mbuf: extend rte_mbuf_prefetch_part* to support more prefetching methods

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Jianbo,

On 06/01/2016 05:29 AM, Jianbo Liu wrote:
>> enum rte_mbuf_prefetch_type {
>> >         PREFETCH0,
>> >         PREFETCH1,
>> > ...
>> > };
>> >
>> > static inline void
>> > rte_mbuf_prefetch_part1(enum rte_mbuf_prefetch_type type,
>> >         struct rte_mbuf *m)
>> > {
>> >         switch (type) {
>> >         case PREFETCH0:
>> >                 rte_prefetch0(&m->cacheline0);
>> >                 break;
>> >         case PREFETCH1:
>> >                 rte_prefetch1(&m->cacheline0);
>> >                 break;
>> >         ...
>> > }
>> >
> How about adding these to forbid the illegal use of this macro?
> enum rte_mbuf_prefetch_type {
>          ENUM_prefetch0,
>          ENUM_prefetch1,
>  ...
> };
> 
> #define RTE_MBUF_PREFETCH_PART1(type, m) \
>     if (ENUM_##type == ENUM_prefretch0) \
>         rte_prefetch0(&(m)->cacheline0);   \
>     else if (ENUM_##type == ENUM_prefetch1) \
>         rte_prefetch1(&(m)->cacheline0); \
>     ....
> 

As Stephen stated, a static inline is better than a macro, mainly
because it is understood by the compiler instead of beeing a dumb
code replacement.

Any reason why you would prefer a macro in that case?

Regards
Olivier