[PATCH] eal/x86: optimize memcpy of small 64-byte blocks

[Konstantin Ananyev]

> > From: Stephen Hemminger [mailto:stephen at networkplumber.org]
> > Sent: Tuesday, 4 August 2026 17.52
> >
> > On Tue,  4 Aug 2026 14:33:04 +0000
> > Morten Brørup <mb at smartsharesystems.com> wrote:
> >
> > > +	/* Common way for small copy size of 64-byte blocks. Unlikely, so
> > constant size only */
> > > +	if (__rte_constant(n) && (n & 63) == 0 && n <=
> > RTE_MEMCPY_BLOCK_64_MAX) {
> > > +		void *ret = dst;
> > > +
> >
> > Maybe just let compiler decide, it will generate vector instructions in
> > most cases.
> >
> > 	if (__rte_constant(n))
> > 		return mempcpy(dst, src, n);
> 
> Maybe in most, but not in all:
> https://godbolt.org/z/KvdKqT5rY

With '-mavx' or '-mavx512f' it looks like it does for your sample code.