Re: [PATCH v4 13/13] eal: provide option to use compiler memcpy instead of RTE

["Mattias Rönnblom" <hofors@lysator.liu.se>]

On Mon, Jun 24, 2024 at 12:05:53PM +0200, Thomas Monjalon wrote:
> 20/06/2024 19:57, Mattias Rönnblom:
> > Provide build option to have functions in <rte_memcpy.h> delegate to
> > the standard compiler/libc memcpy(), instead of using the various
> > custom DPDK, handcrafted, per-architecture rte_memcpy()
> > implementations.
> > 
> > A new meson build option 'use_cc_memcpy' is added. By default,
> > the compiler/libc memcpy() is used.
> > 
> > The performance benefits of the custom DPDK rte_memcpy()
> > implementations have been diminishing with every compiler release, and
> > with current toolchains the use of a custom memcpy() implementation
> > may even be a liability.
> > 
> > This patch leaves an option to stay on the custom DPDK implementations,
> > would that prove beneficial for certain applications or architectures.
> [...]
> > --- a/meson_options.txt
> > +++ b/meson_options.txt
> > +option('use_cc_memcpy', type: 'boolean', value: true, description:
> > +       'Have the functions of <rte_memcpy.h> delegate to compiler/libc memcpy() instead of using custom implementation.')
> 
> I suppose you propose this change for 24.11?
> I would prefer getting the option disabled in 24.07,
> so we can run tests during months before enabling it by default.

I think I would suggest having it included and enabled by default in
24.07, but that is too risky perhaps.

Having it included in 24.07 and disabled by default would be the
conservative option.

> This period would also help to make sure it is compiling in all cases.
> Please could you enable the option in our compilation scripts?
> 
>

I'll give it a try.