[RFC v2] eal: provide option to use compiler memcpy instead of RTE

[Stephen Hemminger]

On Tue, 28 May 2024 10:19:15 +0200
Mattias Rönnblom <hofors at lysator.liu.se> wrote:

> >   
> 
> I've tested this patch some with DSW micro benchmarks, and the result is 
> a 2.5% reduction of the DSW+testapp overhead with cc/libc memcpy. GCC 11.4.
> 
> We've also run characteristic test suite of a large, real world app. 
> Here, we saw no effect. GCC 10.5.
> 
> x86_64 in both cases (Skylake and Raptor Lake).
> 
> Last time we did the same, there were a noticeable performance 
> degradation in both the above cases.
> 
> This is not a lot of data points, but I think it we should consider 
> making the custom RTE memcpy() implementations optional in the next 
> release, and if no-one complains, remove the implementations in the next 
> release.

Lets go farther.

1. Announce that rte_memcpy will be marked deprecated in 24.11 release

2. In 24.11 do a global replace of rte_memcpy on the tree.
   And mark rte_memcpy as deprecated.

3. In 25.11 it can go away.