> On 18 Jun 2020, at 1:34 am, Theo Buehler <t...@theobuehler.org> wrote:
>
> The next step is to use that we have cached the result of the matrix
> multiplication H * val in stoeplitz_cache_entry(scache, val), so the
> identity (H * x) ^ (H * y) == H * (x ^ y) allows us to push the calls to
> the cache function down to the end of stoeplitz_hash_ip{4,6}{,port}().
>
> The result is the mechanical diff below. I have at least one follow-up,
> so it's intentionally minimalistic.
>
> The identity in question was again confirmed by brute force on amd64,
> sparc64 and powerpc for all possible values of skey, x and y.
ok dlg@
>
> Index: toeplitz.c
> ===================================================================
> RCS file: /cvs/src/sys/net/toeplitz.c,v
> retrieving revision 1.2
> diff -u -p -r1.2 toeplitz.c
> --- toeplitz.c 17 Jun 2020 06:36:56 -0000 1.2
> +++ toeplitz.c 17 Jun 2020 06:56:11 -0000
> @@ -118,17 +118,18 @@ stoeplitz_hash_ip4(const struct stoeplit
> {
> uint16_t lo, hi;
>
> - lo = stoeplitz_cache_entry(scache, faddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 16);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 16);
> -
> - hi = stoeplitz_cache_entry(scache, faddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 24);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 24);
> + lo = faddr >> 0;
> + lo ^= faddr >> 16;
> + lo ^= laddr >> 0;
> + lo ^= laddr >> 16;
> +
> + hi = faddr >> 8;
> + hi ^= faddr >> 24;
> + hi ^= laddr >> 8;
> + hi ^= laddr >> 24;
>
> - return (swap16(lo) ^ hi);
> + return (swap16(stoeplitz_cache_entry(scache, lo))
> + ^ stoeplitz_cache_entry(scache, hi));
> }
>
> uint16_t
> @@ -137,21 +138,22 @@ stoeplitz_hash_ip4port(const struct stoe
> {
> uint16_t hi, lo;
>
> - lo = stoeplitz_cache_entry(scache, faddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 16);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 16);
> - lo ^= stoeplitz_cache_entry(scache, fport >> 0);
> - lo ^= stoeplitz_cache_entry(scache, lport >> 0);
> -
> - hi = stoeplitz_cache_entry(scache, faddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 24);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 24);
> - hi ^= stoeplitz_cache_entry(scache, fport >> 8);
> - hi ^= stoeplitz_cache_entry(scache, lport >> 8);
> + lo = faddr >> 0;
> + lo ^= faddr >> 16;
> + lo ^= laddr >> 0;
> + lo ^= laddr >> 16;
> + lo ^= fport >> 0;
> + lo ^= lport >> 0;
> +
> + hi = faddr >> 8;
> + hi ^= faddr >> 24;
> + hi ^= laddr >> 8;
> + hi ^= laddr >> 24;
> + hi ^= fport >> 8;
> + hi ^= lport >> 8;
>
> - return (swap16(lo) ^ hi);
> + return (swap16(stoeplitz_cache_entry(scache, lo))
> + ^ stoeplitz_cache_entry(scache, hi));
> }
>
> #ifdef INET6
> @@ -166,18 +168,19 @@ stoeplitz_hash_ip6(const struct stoeplit
> uint32_t faddr = faddr6->s6_addr32[i];
> uint32_t laddr = laddr6->s6_addr32[i];
>
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 16);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 16);
> -
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 24);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 24);
> + lo ^= faddr >> 0;
> + lo ^= faddr >> 16;
> + lo ^= laddr >> 0;
> + lo ^= laddr >> 16;
> +
> + hi ^= faddr >> 8;
> + hi ^= faddr >> 24;
> + hi ^= laddr >> 8;
> + hi ^= laddr >> 24;
> }
>
> - return (swap16(lo) ^ hi);
> + return (swap16(stoeplitz_cache_entry(scache, lo))
> + ^ stoeplitz_cache_entry(scache, hi));
> }
>
> uint16_t
> @@ -192,24 +195,25 @@ stoeplitz_hash_ip6port(const struct stoe
> uint32_t faddr = faddr6->s6_addr32[i];
> uint32_t laddr = laddr6->s6_addr32[i];
>
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, faddr >> 16);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 0);
> - lo ^= stoeplitz_cache_entry(scache, laddr >> 16);
> -
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, faddr >> 24);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 8);
> - hi ^= stoeplitz_cache_entry(scache, laddr >> 24);
> + lo ^= faddr >> 0;
> + lo ^= faddr >> 16;
> + lo ^= laddr >> 0;
> + lo ^= laddr >> 16;
> +
> + hi ^= faddr >> 8;
> + hi ^= faddr >> 24;
> + hi ^= laddr >> 8;
> + hi ^= laddr >> 24;
> }
>
> - lo ^= stoeplitz_cache_entry(scache, fport >> 0);
> - lo ^= stoeplitz_cache_entry(scache, lport >> 0);
> + lo ^= fport >> 0;
> + lo ^= lport >> 0;
>
> - hi ^= stoeplitz_cache_entry(scache, fport >> 8);
> - hi ^= stoeplitz_cache_entry(scache, lport >> 8);
> + hi ^= fport >> 8;
> + hi ^= lport >> 8;
>
> - return (swap16(lo) ^ hi);
> + return (swap16(stoeplitz_cache_entry(scache, lo))
> + ^ stoeplitz_cache_entry(scache, hi));
> }
> #endif /* INET6 */
>
>
