Re: [PATCH 1/2] net: ethernet address comparison optimizations

Bruce Richardson
2026-01-30T16:24:37Z

On Fri, Jan 30, 2026 at 08:20:28AM -0800, Stephen Hemminger wrote:
> On Fri, 30 Jan 2026 10:46:16 +0000
> Morten Brørup <mb@smartsharesystems.com> wrote:
>
> > +__rte_pure
> > static inline int rte_is_same_ether_addr(const struct rte_ether_addr *ea1,
> > const struct rte_ether_addr *ea2)
> > {
> > +#if !defined(RTE_ARCH_STRICT_ALIGN)
> > + return ((((const unaligned_uint32_t *)ea1)[0] ^ ((const unaligned_uint32_t *)ea2)[0]) |
> > + (((const uint16_t *)ea1)[2] ^ ((const uint16_t *)ea2)[2])) == 0;
> > +#else
> > const uint16_t *w1 = (const uint16_t *)ea1;
> > const uint16_t *w2 = (const uint16_t *)ea2;
> >
> > return ((w1[0] ^ w2[0]) | (w1[1] ^ w2[1]) | (w1[2] ^ w2[2])) == 0;
> > +#endif
> > }
> >
>
> FYI in Linux:
>
> static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
> {
> #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
> u32 fold = ((*(const u32 *)addr1) ^ (*(const u32 *)addr2)) |
> ((*(const u16 *)(addr1 + 4)) ^ (*(const u16 *)(addr2 + 4)));
>
> return fold == 0;
> #else
> const u16 *a = (const u16 *)addr1;
> const u16 *b = (const u16 *)addr2;
>
> return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) == 0;
> #endif
> }
>
> In FreeBSD kernel, there is no helper they just use memcmp

+1 for just memcmp :-)