[ovs-dev] [v4 02/12] dpif-netdev: Add auto validation function for miniflow extract

Flavio Leitner fbl at sysclose.org
Mon Jun 28 02:50:53 UTC 2021


Hi,

I haven't tested the patch set yet.
I left some comments in line.

On Thu, Jun 17, 2021 at 09:57:44PM +0530, Kumar Amber wrote:
> This patch introduced the auto-validation function which
> allows users to compare the batch of packets obtained from
> different miniflow implementations against the linear
> miniflow extract and return a hitmask.
> 
> The autovaidator function can be triggered at runtime using the
> following command:
> 
> $ ovs-appctl dpif-netdev/miniflow-parser-set autovalidator
> 
> Signed-off-by: Kumar Amber <kumar.amber at intel.com>
> Co-authored-by: Harry van Haaren <harry.van.haaren at intel.com>
> Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
> ---
>  lib/dpif-netdev-private-extract.c | 141 ++++++++++++++++++++++++++++++
>  lib/dpif-netdev-private-extract.h |  15 ++++
>  lib/dpif-netdev.c                 |   2 +-
>  3 files changed, 157 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/dpif-netdev-private-extract.c b/lib/dpif-netdev-private-extract.c
> index fcc56ef26..0741c19f9 100644
> --- a/lib/dpif-netdev-private-extract.c
> +++ b/lib/dpif-netdev-private-extract.c
> @@ -32,6 +32,11 @@ VLOG_DEFINE_THIS_MODULE(dpif_netdev_extract);
>  
>  /* Implementations of available extract options. */
>  static struct dpif_miniflow_extract_impl mfex_impls[] = {
> +   {
> +        .probe = NULL,
> +        .extract_func = dpif_miniflow_extract_autovalidator,
> +        .name = "autovalidator",
> +    },

Please define a enum for each entry. Also document that
autovalidator is required to be the first and suggest
to see the comment explaining more on MFEX_IMPL_START_IDX.

>      {
>          .probe = NULL,
>          .extract_func = NULL,
> @@ -84,3 +89,139 @@ dpif_miniflow_extract_info_get(struct dpif_miniflow_extract_impl **out_ptr)
>      *out_ptr = mfex_impls;
>      return ARRAY_SIZE(mfex_impls);
>  }
> +
> +uint32_t
> +dpif_miniflow_extract_autovalidator(struct dp_packet_batch *packets,
> +                                    struct netdev_flow_key *keys,
> +                                    uint32_t keys_size, odp_port_t in_port,
> +                                    void *pmd_handle)
> +{
> +    const size_t cnt = dp_packet_batch_size(packets);
> +    uint16_t good_l2_5_ofs[NETDEV_MAX_BURST];
> +    uint16_t good_l3_ofs[NETDEV_MAX_BURST];
> +    uint16_t good_l4_ofs[NETDEV_MAX_BURST];
> +    uint16_t good_l2_pad_size[NETDEV_MAX_BURST];
> +    struct dp_packet *packet;
> +    struct dp_netdev_pmd_thread *pmd = pmd_handle;
> +    struct dpif_miniflow_extract_impl *miniflow_funcs;
> +
> +    int32_t mfunc_count = dpif_miniflow_extract_info_get(&miniflow_funcs);
> +    if (mfunc_count < 0) {
> +        pmd->miniflow_extract_opt = NULL;
> +        VLOG_ERR("failed to get miniflow extract function implementations\n");

No need for terminating with \n here and other calls to VLOG_*().

> +        return 0;
> +    }

> +    ovs_assert(keys_size >= cnt);
> +    struct netdev_flow_key test_keys[NETDEV_MAX_BURST];
> +
> +    /* Run scalar miniflow_extract to get default result. */
> +    DP_PACKET_BATCH_FOR_EACH (i, packet, packets) {
> +        pkt_metadata_init(&packet->md, in_port);
> +        miniflow_extract(packet, &keys[i].mf);
> +
> +        /* Store known good metadata to compare with optimized metadata. */
> +        good_l2_5_ofs[i] = packet->l2_5_ofs;
> +        good_l3_ofs[i] = packet->l3_ofs;
> +        good_l4_ofs[i] = packet->l4_ofs;
> +        good_l2_pad_size[i] = packet->l2_pad_size;
> +    }
> +
> +    /* Iterate through each version of miniflow implementations. */
> +    for (int j = MFEX_IMPL_START_IDX; j < ARRAY_SIZE(mfex_impls); j++) {
> +        if (!mfex_impls[j].available) {
> +            continue;
> +        }
> +
> +        /* Reset keys and offsets before each implementation. */
> +        memset(test_keys, 0, keys_size * sizeof(struct netdev_flow_key));
> +        DP_PACKET_BATCH_FOR_EACH (i, packet, packets) {
> +            dp_packet_reset_offsets(packet);
> +        }
> +        /* Call optimized miniflow for each batch of packet. */
> +        uint32_t hit_mask = mfex_impls[j].extract_func(packets, test_keys,
> +                                            keys_size, in_port, pmd_handle);
> +
> +        /* Do a miniflow compare for bits, blocks and offsets for all the
> +         * classified packets in the hitmask marked by set bits. */
> +        while (hit_mask) {
> +            /* Index for the set bit. */
> +            uint32_t i = __builtin_ctz(hit_mask);
> +            /* Set the index in hitmask to Zero. */
> +            hit_mask &= (hit_mask - 1);
> +
> +            uint32_t failed = 0;
> +
> +            /* Check miniflow bits are equal. */
> +            if ((keys[i].mf.map.bits[0] != test_keys[i].mf.map.bits[0]) ||
> +                (keys[i].mf.map.bits[1] != test_keys[i].mf.map.bits[1])) {
> +                VLOG_ERR("Good 0x%llx 0x%llx\tTest 0x%llx 0x%llx\n",
> +                         keys[i].mf.map.bits[0], keys[i].mf.map.bits[1],
> +                         test_keys[i].mf.map.bits[0],
> +                         test_keys[i].mf.map.bits[1]);
> +                failed = 1;
> +            }
> +
> +            if (!miniflow_equal(&keys[i].mf, &test_keys[i].mf)) {
> +                uint32_t block_cnt = miniflow_n_values(&keys[i].mf);
> +                VLOG_ERR("Autovalidation blocks failed for %s pkt %d",
> +                         mfex_impls[j].name, i);
> +                VLOG_ERR("  Good hexdump:\n");
> +                uint64_t *good_block_ptr = (uint64_t *)&keys[i].buf;
> +                uint64_t *test_block_ptr = (uint64_t *)&test_keys[i].buf;
> +                for (uint32_t b = 0; b < block_cnt; b++) {
> +                    VLOG_ERR("    %"PRIx64"\n", good_block_ptr[b]);
> +                }
> +                VLOG_ERR("  Test hexdump:\n");
> +                for (uint32_t b = 0; b < block_cnt; b++) {
> +                    VLOG_ERR("    %"PRIx64"\n", test_block_ptr[b]);
> +                }
> +                failed = 1;
> +            }
> +

What do you think of doing this instead:
               packet = packets->packets[i];
               if ((packet->l2_pad_size != good_l2_pad_size[i]) ||
               ...

> +            if ((packets->packets[i]->l2_pad_size != good_l2_pad_size[i]) ||

> +                    (packets->packets[i]->l2_5_ofs != good_l2_5_ofs[i]) ||
> +                    (packets->packets[i]->l3_ofs != good_l3_ofs[i]) ||
> +                    (packets->packets[i]->l4_ofs != good_l4_ofs[i])) {
> +                VLOG_ERR("Autovalidation packet offsets failed for %s pkt %d",
> +                         mfex_impls[j].name, i);
> +                VLOG_ERR("  Good offsets: l2_pad_size %u, l2_5_ofs : %u"
> +                         " l3_ofs %u, l4_ofs %u\n",
> +                         good_l2_pad_size[i], good_l2_5_ofs[i],
> +                         good_l3_ofs[i], good_l4_ofs[i]);
> +                VLOG_ERR("  Test offsets: l2_pad_size %u, l2_5_ofs : %u"
> +                         " l3_ofs %u, l4_ofs %u\n",
> +                         packets->packets[i]->l2_pad_size,
> +                         packets->packets[i]->l2_5_ofs,
> +                         packets->packets[i]->l3_ofs,
> +                         packets->packets[i]->l4_ofs);
> +                failed = 1;
> +            }
> +
> +            if (failed) {
> +                /* Having dumped the debug info, disable autovalidator. */
> +                VLOG_ERR("Autovalidation failed in %s pkt %d, disabling.\n",
> +                         mfex_impls[j].name, i);
> +                /* Halt OVS here on debug builds. */
> +                ovs_assert(0);
> +                pmd->miniflow_extract_opt = NULL;
> +                break;
> +            }
> +        }
> +    }
> +
> +    /* preserve packet correctness by storing back the good offsets in
> +     * packets back. */
> +    DP_PACKET_BATCH_FOR_EACH (i, packet, packets) {
> +        packet->l2_5_ofs = good_l2_5_ofs[i];
> +        packet->l3_ofs = good_l3_ofs[i];
> +        packet->l4_ofs = good_l4_ofs[i];
> +        packet->l2_pad_size = good_l2_pad_size[i];
> +    }
> +
> +    /* Returning zero implies no packets were hit by autovalidation. This
> +     * simplifies unit-tests as changing --enable-mfex-default-autovalidator
> +     * would pass/fail. By always returning zero, autovalidator is a little
> +     * slower, but we gain consistency in testing.
> +     */
> +    return 0;
> +}
> diff --git a/lib/dpif-netdev-private-extract.h b/lib/dpif-netdev-private-extract.h
> index b7b0b2be4..455a7b590 100644
> --- a/lib/dpif-netdev-private-extract.h
> +++ b/lib/dpif-netdev-private-extract.h
> @@ -24,6 +24,11 @@
>  /* Max size of dpif_miniflow_extract_impl array. */
>  #define MFEX_IMPLS_MAX_SIZE (16)
>  
> +/* Skip the autovalidator study and null when iterating all available
> + * miniflow implementations.
> + */
> +#define MFEX_IMPL_START_IDX (1)
> +

As pointed above, this should come from an enum.


>  /* Forward declarations. */
>  struct dp_packet;
>  struct miniflow;
> @@ -90,5 +95,15 @@ dpif_miniflow_extract_init(void);
>  int32_t
>  dpif_miniflow_extract_info_get(struct dpif_miniflow_extract_impl **out_ptr);
>  
> +/* Retrieve the hitmask of the batch of pakcets which is obtained by comparing
> + * different miniflow implementations with linear miniflow extract.
> + * On error, returns a zero.
> + * On success, returns the number of packets in the batch compared.
> + */
> +uint32_t
> +dpif_miniflow_extract_autovalidator(struct dp_packet_batch *batch,
> +                                    struct netdev_flow_key *keys,
> +                                    uint32_t keys_size, odp_port_t in_port,
> +                                    void *pmd_handle);
>  
>  #endif /* DPIF_NETDEV_AVX512_EXTRACT */
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 567ebd952..4f4ab2790 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -1181,8 +1181,8 @@ dpif_miniflow_extract_impl_set(struct unixctl_conn *conn, int argc,
>      struct ds reply = DS_EMPTY_INITIALIZER;
>      ds_put_format(&reply, "Miniflow implementation set to %s.\n", mfex_name);
>      const char *reply_str = ds_cstr(&reply);
> -    unixctl_command_reply(conn, reply_str);
>      VLOG_INFO("%s", reply_str);
> +    unixctl_command_reply(conn, reply_str);
>      ds_destroy(&reply);
>  }
>  
> -- 
> 2.25.1
> 
> _______________________________________________
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> dev at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev

-- 
fbl


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