> -----Original Message-----
> From: Ilya Maximets <[email protected]>
> Sent: Wednesday 7 December 2022 19:11
> To: Finn, Emma <[email protected]>; [email protected]
> Cc: [email protected]; Van Haaren, Harry <[email protected]>;
> [email protected]; Stokes, Ian <[email protected]>
> Subject: Re: [v7] odp-execute: Add ISA implementation of set_masked IPv6
> action
>
> On 12/6/22 17:19, Emma Finn 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.
> >
> > Here are some relative performance numbers for this patch:
> > +-----------------------------+----------------+
> > | Actions | AVX with patch |
> > +-----------------------------+----------------+
> > | ipv6_src | 1.14x |
> > +-----------------------------+----------------+
> > | ipv6_src + ipv6_dst | 1.40x |
> > +-----------------------------+----------------+
> > | ipv6_label | 1.14x |
> > +-----------------------------+----------------+
> > | mod_ipv6 4 x field | 1.43x |
> > +-----------------------------+----------------+
> >
> > Signed-off-by: Emma Finn <[email protected]>
> >
> > ---
> > v7:
> > - Added clearing of connection tracking fields.
> > v6:
> > - Added check for ipv6 extension headers.
> > v5:
> > - Fixed load for ip6 src and dst mask for checksum check.
> > v4:
> > - Reworked and moved check for checksum outside loop.
> > - Code cleanup based on review from Eelco.
> > v3:
> > - Added a runtime check for AVX512 vbmi.
> > v2:
> > - Added check for availbility of s6_addr32 field of struct in6_addr.
> > - Fixed network headers for freebsd builds.
> > ---
> > ---
> > lib/odp-execute-avx512.c | 220
> > ++++++++++++++++++++++++++++++++++++++
> > lib/odp-execute-private.c | 14 +++
> > lib/odp-execute-private.h | 1 +
> > lib/packets.c | 2 +-
> > lib/packets.h | 2 +
> > 5 files changed, 238 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/odp-execute-avx512.c b/lib/odp-execute-avx512.c index
> > 66b3998da..b2131c0fa 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"
> > @@ -28,6 +31,7 @@
> > #include "odp-execute-private.h"
> > #include "odp-netlink.h"
> > #include "openvswitch/vlog.h"
> > +#include "packets.h"
> >
> > VLOG_DEFINE_THIS_MODULE(odp_execute_avx512);
> >
> > @@ -75,6 +79,26 @@ BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv4,
> ipv4_tos) +
> > MEMBER_SIZEOF(struct ovs_key_ipv4, ipv4_tos) ==
> > offsetof(struct ovs_key_ipv4, ipv4_ttl));
> >
> > +BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv6, ipv6_src) +
> > + MEMBER_SIZEOF(struct ovs_key_ipv6, ipv6_src) ==
> > + offsetof(struct ovs_key_ipv6, ipv6_dst));
> > +
> > +BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv6, ipv6_dst) +
> > + MEMBER_SIZEOF(struct ovs_key_ipv6, ipv6_dst) ==
> > + offsetof(struct ovs_key_ipv6, ipv6_label));
> > +
> > +BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv6, ipv6_label) +
> > + MEMBER_SIZEOF(struct ovs_key_ipv6, ipv6_label) ==
> > + offsetof(struct ovs_key_ipv6, ipv6_proto));
> > +
> > +BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv6, ipv6_proto) +
> > + MEMBER_SIZEOF(struct ovs_key_ipv6, ipv6_proto) ==
> > + offsetof(struct ovs_key_ipv6, ipv6_tclass));
> > +
> > +BUILD_ASSERT_DECL(offsetof(struct ovs_key_ipv6, ipv6_tclass) +
> > + MEMBER_SIZEOF(struct ovs_key_ipv6, ipv6_tclass) ==
> > + offsetof(struct ovs_key_ipv6, ipv6_hlimit));
> > +
> > /* Array of callback functions, one for each masked operation. */
> > odp_execute_action_cb
> impl_set_masked_funcs[__OVS_KEY_ATTR_MAX];
> >
> > @@ -485,6 +509,196 @@ action_avx512_ipv4_set_addrs(struct
> dp_packet_batch *batch,
> > }
> > }
> >
> > +#if HAVE_AVX512VBMI
> > +static inline uint16_t ALWAYS_INLINE
> > +__attribute__((__target__("avx512vbmi")))
> > +avx512_ipv6_sum_header(__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);
> > +
> > + /* Shuffle ip6 src and dst to beginning of register. */
> > + __m512i v_ip6_hdr_shuf =
> _mm512_permutexvar_epi64(v_shuf_src_dst,
> > + ip6_header);
> > +
> > + /* Extract ip6 src and dst into smaller 256-bit wide register. */
> > + __m256i v_ip6_src_dst = _mm512_extracti64x4_epi64(v_ip6_hdr_shuf,
> > + 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 old_delta = avx512_ipv6_sum_header(old_header);
> > + uint16_t new_delta = avx512_ipv6_sum_header(new_header);
> > + uint32_t csum_delta = ((uint16_t) ~old_delta) + new_delta;
> > +
> > + return ~csum_finish(csum_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_set_ipv6(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);
> > +
> > + /* Set the v_zero register to all zero's. */
> > + const __m128i v_zeros = _mm_setzero_si128();
> > +
> > + /* Set the v_all_ones register to all one's. */
> > + const __m128i v_all_ones = _mm_cmpeq_epi16(v_zeros, v_zeros);
> > +
> > + /* Load ip6 src and dst masks respectively into 128-bit wide
> > registers. */
> > + __m128i v_src = _mm_loadu_si128((void *) &mask->ipv6_src);
> > + __m128i v_dst = _mm_loadu_si128((void *) &mask->ipv6_dst);
> > +
> > + /* Perform a bitwise OR between src and dst registers. */
> > + __m128i v_or = _mm_or_si128(v_src, v_dst);
> > +
> > + /* Will return true if any bit has been set in v_or, else it will
> > return
> > + * false. */
> > + bool do_checksum = !_mm_test_all_zeros(v_or, v_all_ones);
> > +
> > + 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. */
> > + uint8_t proto = 0;
> > + bool rh_present;
> > + bool do_csum = do_checksum;
> > +
> > + rh_present = packet_rh_present(packet, &proto, &do_csum);
> > +
> > + if (do_csum) {
> > + __m512i v_new_hdr_for_cksum = v_new_hdr;
> > + uint16_t delta_checksum;
> > +
> > + /* In case of routing header being present, checksum should
> > not be
> > + * updated for the destination address. */
> > + if (rh_present) {
> > + v_new_hdr_for_cksum = _mm512_mask_blend_epi64(0x18,
> v_new_hdr,
> > + v_packet);
> > + }
> > +
> > + delta_checksum = avx512_ipv6_addr_csum_delta(v_packet,
> > +
> > + v_new_hdr_for_cksum);
> > +
> > + if (proto == IPPROTO_UDP) {
>
> Similar to ipv4 case, packet_update_csum128() has l4_size checks in these
> conditions to protect from truncated packets.
>
> Such checks should be added here as well.
>
Yes, I will add checks here too and send out a new version of ipv6 patch.
> > + 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_icmp6_checksum = ~icmp->icmp6_cksum;
> > + uint32_t icmp6_checksum = old_icmp6_checksum +
> > + delta_checksum;
> > +
> > + icmp6_checksum = csum_finish(icmp6_checksum);
> > + icmp->icmp6_cksum = icmp6_checksum;
> > + }
> > +
> > + pkt_metadata_init_conn(&packet->md);
> > + }
> > + /* Write back the modified IPv6 addresses. */
> > + _mm512_mask_storeu_epi64((void *) nh, 0x1F, v_new_hdr);
> > + }
> > +}
> > +#endif /* HAVE_AVX512VBMI */
> > +
> > static void
> > action_avx512_set_masked(struct dp_packet_batch *batch, const struct
> > nlattr *a) { @@ -516,6 +730,12 @@ action_avx512_init(struct
> > odp_execute_action_impl *self OVS_UNUSED)
> > 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
> > + if (action_avx512vbmi_isa_probe()) {
> > + impl_set_masked_funcs[OVS_KEY_ATTR_IPV6] =
> action_avx512_set_ipv6;
> > + }
> > +#endif
> > +
> > return 0;
> > }
> >
> > diff --git a/lib/odp-execute-private.c b/lib/odp-execute-private.c
> > index 57be5cfe7..8b7a6b4ab 100644
> > --- a/lib/odp-execute-private.c
> > +++ b/lib/odp-execute-private.c
> > @@ -60,6 +60,20 @@ action_avx512_isa_probe(void)
> >
> > #endif
> >
> > +#if ACTION_IMPL_AVX512_CHECK && HAVE_AVX512VBMI bool
> > +action_avx512vbmi_isa_probe(void)
> > +{
> > + return cpu_has_isa(OVS_CPU_ISA_X86_AVX512VBMI);
> > +}
> > +#else
> > +bool
> > +action_avx512vbmi_isa_probe(void)
> > +{
> > + return false;
> > +}
> > +#endif
> > +
> > static struct odp_execute_action_impl action_impls[] = {
> > [ACTION_IMPL_AUTOVALIDATOR] = {
> > .available = false,
> > diff --git a/lib/odp-execute-private.h b/lib/odp-execute-private.h
> > index 940180c99..643f41c2a 100644
> > --- a/lib/odp-execute-private.h
> > +++ b/lib/odp-execute-private.h
> > @@ -78,6 +78,7 @@
> BUILD_ASSERT_DECL(ACTION_IMPL_AUTOVALIDATOR == 1);
> > #define ACTION_IMPL_BEGIN (ACTION_IMPL_AUTOVALIDATOR + 1)
> >
> > bool action_avx512_isa_probe(void);
> > +bool action_avx512vbmi_isa_probe(void);
> >
> > /* Odp execute init handles setting up the state of the actions functions
> > at
> > * initialization time. It cannot return errors, as it must always
> > succeed in diff --git a/lib/packets.c b/lib/packets.c index
> > 1dcd4a6fc..06f516cb1 100644
> > --- a/lib/packets.c
> > +++ b/lib/packets.c
> > @@ -1152,7 +1152,7 @@ packet_set_ipv4_addr(struct dp_packet *packet,
> > * segements_left > 0.
> > *
> > * This function assumes that L3 and L4 offsets are set in the
> > packet. */ -static bool
> > +bool
> > packet_rh_present(struct dp_packet *packet, uint8_t *nexthdr, bool
> > *first_frag) {
> > const struct ovs_16aligned_ip6_hdr *nh; diff --git
> > a/lib/packets.h b/lib/packets.h index 5bdf6e4bb..8626aac8d 100644
> > --- a/lib/packets.h
> > +++ b/lib/packets.h
> > @@ -1642,6 +1642,8 @@ void packet_put_ra_prefix_opt(struct dp_packet
> *,
> > ovs_be32 preferred_lifetime,
> > const ovs_be128 router_prefix);
> > uint32_t packet_csum_pseudoheader(const struct ip_header *);
> > +bool packet_rh_present(struct dp_packet *packet, uint8_t *nexthdr,
> > + bool *first_frag);
> > void IP_ECN_set_ce(struct dp_packet *pkt, bool is_ipv6);
> >
> > #define DNS_HEADER_LEN 12
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