> -----Original Message-----
> From: David Marchand <[email protected]>
> Sent: Wednesday 21 September 2022 11:26
> To: Finn, Emma <[email protected]>
> Cc: [email protected]; [email protected]
> Subject: Re: [ovs-dev] [v2] odp-execute: Add ISA implementation of
> set_masked IPv6 action
>
> On Tue, Sep 20, 2022 at 3:19 PM Emma Finn <[email protected]> wrote:
> >
> > This commit adds support for the AVX512 implementation of the
> > ipv6_set_addrs action as well as an AVX512 implementation of updating
> > the L4 checksums.
> >
> > Signed-off-by: Emma Finn <[email protected]>
> >
> > ---
> > v2:
> > - Added check for availbility of s6_addr32 field of struct in6_addr.
> > - Fixed network headers for freebsd builds.
> > ---
> > ---
> > lib/odp-execute-avx512.c | 172
> > +++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 172 insertions(+)
> >
> > diff --git a/lib/odp-execute-avx512.c b/lib/odp-execute-avx512.c index
> > 6c7713251..58d1746c9 100644
> > --- a/lib/odp-execute-avx512.c
> > +++ b/lib/odp-execute-avx512.c
> > @@ -20,6 +20,9 @@
> >
> > #include <config.h>
> > #include <errno.h>
> > +#include <sys/types.h>
> > +#include <netinet/in.h>
> > +#include <netinet/ip6.h>
> >
> > #include "csum.h"
> > #include "dp-packet.h"
> > @@ -483,6 +486,172 @@ action_avx512_ipv4_set_addrs(struct
> dp_packet_batch *batch,
> > }
> > }
> >
> > +#if HAVE_AVX512VBMI
> > +static inline uint16_t ALWAYS_INLINE
> > +__attribute__((__target__("avx512vbmi")))
> > +avx512_ipv6_get_delta(__m512i ip6_header) {
> > + __m256i v_zeros = _mm256_setzero_si256();
> > + __m512i v_shuf_src_dst = _mm512_setr_epi64(0x01, 0x02, 0x03, 0x04,
> > + 0xFF, 0xFF, 0xFF,
> > +0xFF);
> > +
> > + __m512i v_header = _mm512_permutexvar_epi64(v_shuf_src_dst,
> ip6_header);
> > + __m256i v_ip6_src_dst = _mm512_extracti64x4_epi64(v_header, 0);
> > + /* These two shuffle masks, v_swap16a and v_swap16b, are to shuffle
> the
> > + * src and dst fields and add padding after each 16-bit value for the
> > + * following carry over addition. */
> > + __m256i v_swap16a = _mm256_setr_epi16(0x0100, 0xFFFF, 0x0302,
> 0xFFFF,
> > + 0x0504, 0xFFFF, 0x0706, 0xFFFF,
> > + 0x0100, 0xFFFF, 0x0302, 0xFFFF,
> > + 0x0504, 0xFFFF, 0x0706, 0xFFFF);
> > + __m256i v_swap16b = _mm256_setr_epi16(0x0908, 0xFFFF, 0x0B0A,
> 0xFFFF,
> > + 0x0D0C, 0xFFFF, 0x0F0E, 0xFFFF,
> > + 0x0908, 0xFFFF, 0x0B0A, 0xFFFF,
> > + 0x0D0C, 0xFFFF, 0x0F0E, 0xFFFF);
> > + __m256i v_shuf_old1 = _mm256_shuffle_epi8(v_ip6_src_dst,
> v_swap16a);
> > + __m256i v_shuf_old2 = _mm256_shuffle_epi8(v_ip6_src_dst,
> > + v_swap16b);
> > +
> > + /* Add each part of the old and new headers together. */
> > + __m256i v_delta = _mm256_add_epi32(v_shuf_old1, v_shuf_old2);
> > +
> > + /* Perform horizontal add to go from 8x32-bits to 2x32-bits. */
> > + v_delta = _mm256_hadd_epi32(v_delta, v_zeros);
> > + v_delta = _mm256_hadd_epi32(v_delta, v_zeros);
> > +
> > + /* Shuffle 32-bit value from 3rd lane into first lane for final
> > + * horizontal add. */
> > + __m256i v_swap32a = _mm256_setr_epi32(0x0, 0x4, 0xF, 0xF,
> > + 0xF, 0xF, 0xF, 0xF);
> > + v_delta = _mm256_permutexvar_epi32(v_swap32a, v_delta);
> > +
> > + v_delta = _mm256_hadd_epi32(v_delta, v_zeros);
> > + v_delta = _mm256_hadd_epi16(v_delta, v_zeros);
> > +
> > + /* Extract delta value. */
> > + return _mm256_extract_epi16(v_delta, 0); }
> > +
> > +static inline uint16_t ALWAYS_INLINE
> > +__attribute__((__target__("avx512vbmi")))
> > +avx512_ipv6_addr_csum_delta(__m512i old_header, __m512i
> new_header) {
> > + uint16_t delta;
> > + uint16_t old_delta = avx512_ipv6_get_delta(old_header);
> > + uint16_t new_delta = avx512_ipv6_get_delta(new_header);
> > + old_delta = ~old_delta;
> > + uint32_t csum_delta = old_delta + new_delta;
> > + delta = csum_finish(csum_delta);
> > +
> > + return ~delta;
> > +}
> > +
> > +/* This function performs the same operation on each packet in the
> > +batch as
> > + * the scalar odp_set_ipv6() function. */ static void
> > +__attribute__((__target__("avx512vbmi")))
> > +action_avx512_ipv6_set_addrs(struct dp_packet_batch *batch,
> > + const struct nlattr *a) {
> > + const struct ovs_key_ipv6 *key, *mask;
> > + struct dp_packet *packet;
> > + a = nl_attr_get(a);
> > + key = nl_attr_get(a);
> > + mask = odp_get_key_mask(a, struct ovs_key_ipv6);
> > +
> > + /* Read the content of the key and mask in the respective registers. We
> > + * only load the size of the actual structure, which is only 40 bytes.
> > */
> > + __m512i v_key = _mm512_maskz_loadu_epi64(0x1F, (void *) key);
> > + __m512i v_mask = _mm512_maskz_loadu_epi64(0x1F, (void *) mask);
> > +
> > + /* This shuffle mask v_shuffle, is to shuffle key and mask to match the
> > + * ip6_hdr structure layout. */
> > + static const uint8_t ip_shuffle_mask[64] = {
> > + 0x20, 0x21, 0x22, 0x23, 0xFF, 0xFF, 0x24, 0x26,
> > + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
> > + 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
> > + 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
> > + 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
> > + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0XFF, 0xFF, 0xFF,
> > + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
> > + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0XFF, 0xFF
> > + };
> > +
> > + __m512i v_shuffle = _mm512_loadu_si512((void *) ip_shuffle_mask);
> > +
> > + /* This shuffle is required for key and mask to match the layout of the
> > + * ip6_hdr struct. */
> > + __m512i v_key_shuf = _mm512_permutexvar_epi8(v_shuffle, v_key);
> > + __m512i v_mask_shuf = _mm512_permutexvar_epi8(v_shuffle,
> v_mask);
> > +
> > + DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
> > + struct ovs_16aligned_ip6_hdr *nh = dp_packet_l3(packet);
> > +
> > + /* Load the 40 bytes of the IPv6 header. */
> > + __m512i v_packet = _mm512_maskz_loadu_epi64(0x1F, (void *)
> > + nh);
> > +
> > + /* AND the v_pkt_mask to the packet data (v_packet). */
> > + __m512i v_pkt_masked = _mm512_andnot_si512(v_mask_shuf,
> > + v_packet);
> > +
> > + /* OR the new addresses (v_key_shuf) with the masked packet
> addresses
> > + * (v_pkt_masked). */
> > + __m512i v_new_hdr = _mm512_or_si512(v_key_shuf,
> > + v_pkt_masked);
> > +
> > + /* If ip6_src or ip6_dst has been modified, L4 checksum needs to
> > + * be updated. */
> > + bool do_checksum = false;
> > +#ifdef s6_addr32
> > + for (int j = 0; j < 4; j++) {
> > + if (mask->ipv6_dst.s6_addr32[j] ||
> > mask->ipv6_src.s6_addr32[j]) {
> > + do_checksum = true;
> > + }
> > + }
> > +#else
> > + for (int j = 0; j < 16; j++) {
> > + if (mask->ipv6_dst.s6_addr[j] || mask->ipv6_src.s6_addr[j]) {
> > + do_checksum = true;
> > + }
> > + }
> > +#endif
> > + if (do_checksum) {
> > + uint8_t proto = nh->ip6_nxt;
> > + uint16_t delta_checksum =
> avx512_ipv6_addr_csum_delta(v_packet,
> > +
> > +v_new_hdr);
> > +
> > + if (proto == IPPROTO_UDP) {
> > + struct udp_header *uh = dp_packet_l4(packet);
> > + if (uh->udp_csum) {
> > + uint16_t old_udp_checksum = ~uh->udp_csum;
> > + uint32_t udp_checksum = old_udp_checksum +
> delta_checksum;
> > + udp_checksum = csum_finish(udp_checksum);
> > +
> > + if (!udp_checksum) {
> > + udp_checksum = htons(0xffff);
> > + }
> > +
> > + uh->udp_csum = udp_checksum;
> > + }
> > + } else if (proto == IPPROTO_TCP) {
> > + struct tcp_header *th = dp_packet_l4(packet);
> > + uint16_t old_tcp_checksum = ~th->tcp_csum;
> > + uint32_t tcp_checksum = old_tcp_checksum + delta_checksum;
> > + tcp_checksum = csum_finish(tcp_checksum);
> > +
> > + th->tcp_csum = tcp_checksum;
> > + } else if (proto == IPPROTO_ICMPV6) {
> > + struct icmp6_header *icmp = dp_packet_l4(packet);
> > + uint16_t old_icmp_checksum = ~icmp->icmp6_cksum;
> > + uint32_t icmp6_checksum = old_icmp_checksum +
> delta_checksum;
> > + icmp6_checksum = csum_finish(icmp6_checksum);
> > +
> > + icmp->icmp6_cksum = icmp6_checksum;
> > + }
> > + }
> > + /* Write back the modified IPv6 addresses. */
> > + _mm512_mask_storeu_epi64((void *) nh, 0x1F, v_new_hdr);
> > + }
> > +}
> > +#endif
> > +
> > static void
> > action_avx512_set_masked(struct dp_packet_batch *batch, const struct
> > nlattr *a) { @@ -513,6 +682,9 @@ action_avx512_init(struct
> > odp_execute_action_impl *self OVS_UNUSED)
> > * SET_MASKED action. */
> > impl_set_masked_funcs[OVS_KEY_ATTR_ETHERNET] =
> action_avx512_eth_set_addrs;
> > impl_set_masked_funcs[OVS_KEY_ATTR_IPV4] =
> > action_avx512_ipv4_set_addrs;
> > +#if HAVE_AVX512VBMI
> > + impl_set_masked_funcs[OVS_KEY_ATTR_IPV6] =
> > +action_avx512_ipv6_set_addrs; #endif
> >
>
> I did not review the AVX512 stuff, neither test the patch.
> One comment though.
>
> All I see are build checks on vbmi availability.
> Don't we need a runtime check for AVX512 platforms that don't have vbmi?
>
>
Thanks for looking at this, good catch.
I will add runtime checks for vmbi in the next revision.
Thanks,
Emma
> --
> David Marchand
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
