[ovs-dev] [v8 06/12] dpif-netdev: Add packet count and core id paramters for study

Flavio Leitner fbl at sysclose.org
Sun Jul 11 00:44:07 UTC 2021


Hi,

On Fri, Jul 09, 2021 at 05:35:56PM +0530, kumar Amber wrote:
> From: Kumar Amber <kumar.amber at intel.com>
> 
> This commit introduces additional command line paramter

Parameter.

> for mfex study function. If user provides additional packet out
> it is used in study to compare minimum packets which must be processed
> else a default value is choosen.
> Also introduces a third paramter for choosing a particular pmd core.
> 
> $ ovs-appctl dpif-netdev/miniflow-parser-set study 500 3
> 
> Signed-off-by: Kumar Amber <kumar.amber at intel.com>
> 
> ---
> v7:
> - change the command paramters for core_id and study_pkt_cnt
> v5:
> - fix review comments(Ian, Flavio, Eelco)
> - introucde pmd core id parameter
> ---
> ---
>  Documentation/topics/dpdk/bridge.rst |  39 +++++++-
>  lib/dpif-netdev-extract-study.c      |  26 ++++-
>  lib/dpif-netdev-private-extract.c    |   2 +-
>  lib/dpif-netdev-private-extract.h    |   9 ++
>  lib/dpif-netdev.c                    | 138 +++++++++++++++++++++++++--
>  5 files changed, 200 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/topics/dpdk/bridge.rst b/Documentation/topics/dpdk/bridge.rst
> index 4db416ddd..8ed810f34 100644
> --- a/Documentation/topics/dpdk/bridge.rst
> +++ b/Documentation/topics/dpdk/bridge.rst
> @@ -284,12 +284,47 @@ command also shows whether the CPU supports each implementation ::
>  
>  An implementation can be selected manually by the following command ::
>  
> -    $ ovs-appctl dpif-netdev/miniflow-parser-set study
> +    $ ovs-appctl dpif-netdev/miniflow-parser-set [-pmd core_id] [name]
> +                                                 [study_cnt]
> +
> +The above command has two optional parameters study_cnt and core_id which can
> +be set optionally. The first parameter core_id to set a particular miniflow

The above command has two optional parameters: study_cnt and
core_id. The core_id set a particular miniflow...

> +extract function to a specific pmd thread on the core. Third parameter
> +study_cnt is specific to study where how many packets needed to choose best
> +implementation can be provided.. In case of any other implementation other
> +than study third parameter [study_cnt] can pe provided with any arbitatry
> +number and is ignored.

Third parameter study_cnt, which is specific to study and ignored by
other implementations, means how many packets are needed to choose the
best implementation.



>  
>  Also user can select the study implementation which studies the traffic for

The user can select...

>  a specific number of packets by applying all available implementaions of
>  miniflow extract and than chooses the one with most optimal result for that
> -traffic pattern.
> +traffic pattern. A user can also provide an additional packet count parameter

The user can optionally provide an packet count [study_cnt]
parameter...

> +which is the minimum number of packets that OVS must study before choosing an
> +optimal implementation. If no packet count is provided, then the default value,
> +128 is chosen. Also, as there is no synchronization point between threads, one
> +PMD thread might still be running a previous round, and can now decide on
> +earlier data.
> +
> +The per packet count is a global value, and parallel `study()` executions with
> +differing packet counts will use the most recent count value provided by usser.
> +
> +Study can be selected with packet count by the following command ::
> +
> +    $ ovs-appctl dpif-netdev/miniflow-parser-set study 1024
> +
> +Study can be selected with packet count and explicit PMD selection
> +by the following command ::
> +
> +    $ ovs-appctl dpif-netdev/miniflow-parser-set -pmd 3 study 1024
> +
> +In the above command the last parameter is the CORE ID of the PMD
> +thread and this can also be used to explicitly set the miniflow
> +extraction function pointer on different PMD threads.
> +
> +Scalar can be selected on core 3 by the following command where
> +study count can be put as any arbitary number or left blank::
> +
> +    $ ovs-appctl dpif-netdev/miniflow-parser-set -pmd 3 scalar
>  
>  Miniflow Extract Validation
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> diff --git a/lib/dpif-netdev-extract-study.c b/lib/dpif-netdev-extract-study.c
> index f14464b2b..d29523db0 100644
> --- a/lib/dpif-netdev-extract-study.c
> +++ b/lib/dpif-netdev-extract-study.c
> @@ -28,7 +28,7 @@ VLOG_DEFINE_THIS_MODULE(dpif_mfex_extract_study);
>  /* Max count of packets to be compared. */
>  #define MFEX_MAX_COUNT (128)
>  
> -static uint32_t mfex_study_pkts_count = 0;
> +static uint32_t mfex_study_pkts_count = MFEX_MAX_COUNT;
>  
>  /* Struct to hold miniflow study stats. */
>  struct study_stats {
> @@ -51,6 +51,28 @@ mfex_study_get_study_stats_ptr(void)
>      return stats;
>  }
>  
> +uint32_t mfex_set_study_pkt_cnt(uint32_t pkt_cmp_count,
> +                                const char *name)
> +{
> +    struct dpif_miniflow_extract_impl *miniflow_funcs;
> +    dpif_mfex_impl_info_get(&miniflow_funcs);
> +
> +    /* If the packet count is set and implementation called is study then
> +     * set packet counter to requested number else set the packet counter
> +     * to default number.
> +     */
> +    if ((strcmp(miniflow_funcs[MFEX_IMPL_STUDY].name, name) == 0) &&
> +        (pkt_cmp_count != 0)) {
> +
> +        atomic_uintptr_t *study_pck_cnt = (void *)&mfex_study_pkts_count;
> +        atomic_store_relaxed(study_pck_cnt, (uintptr_t) pkt_cmp_count );
> +
> +        return 0;
> +    }
> +
> +    return -EINVAL;
> +}
> +
>  uint32_t
>  mfex_study_traffic(struct dp_packet_batch *packets,
>                     struct netdev_flow_key *keys,
> @@ -93,7 +115,7 @@ mfex_study_traffic(struct dp_packet_batch *packets,
>      /* Choose the best implementation after a minimum packets have been
>       * processed.
>       */
> -    if (stats->pkt_count >= MFEX_MAX_COUNT) {
> +    if (stats->pkt_count >= mfex_study_pkts_count) {
>          uint32_t best_func_index = MFEX_IMPL_START_IDX;
>          uint32_t max_hits = 0;
>          for (int i = MFEX_IMPL_START_IDX; i < impl_count; i++) {
> diff --git a/lib/dpif-netdev-private-extract.c b/lib/dpif-netdev-private-extract.c
> index be8c69408..f3d593d39 100644
> --- a/lib/dpif-netdev-private-extract.c
> +++ b/lib/dpif-netdev-private-extract.c
> @@ -122,7 +122,7 @@ dp_mfex_impl_get(struct ds *reply, struct dp_netdev_pmd_thread **pmd_list,
>  
>      for (int i = 0; i < ARRAY_SIZE(mfex_impls); i++) {
>  
> -        ds_put_format(reply, "  %s (available: %s)(pmds: ",
> +        ds_put_format(reply, "  %s (available: %s, pmds: ",

This should be in the patch introducing that line
to avoid the issue in the first place.


>                        mfex_impls[i].name, mfex_impls[i].available ?
>                        "True" : "False");
>  
> diff --git a/lib/dpif-netdev-private-extract.h b/lib/dpif-netdev-private-extract.h
> index 802496cb9..bea532115 100644
> --- a/lib/dpif-netdev-private-extract.h
> +++ b/lib/dpif-netdev-private-extract.h
> @@ -146,4 +146,13 @@ mfex_study_traffic(struct dp_packet_batch *packets,
>                     uint32_t keys_size, odp_port_t in_port,
>                     struct dp_netdev_pmd_thread *pmd_handle);
>  
> +/* Sets the packet count from user to the stats for use in
> + * study function to match against the classified packets to choose
> + * the optimal implementation.
> + * On error, returns EINVAL.
> + * On success, returns 0.
> + */
> +uint32_t mfex_set_study_pkt_cnt(uint32_t pkt_cmp_count,
> +                                const char *name);
> +
>  #endif /* MFEX_AVX512_EXTRACT */
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index b416dc80c..87156fc69 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -1079,17 +1079,49 @@ static void
>  dpif_miniflow_extract_impl_set(struct unixctl_conn *conn, int argc,
>                       const char *argv[], void *aux OVS_UNUSED)
>  {
> -    /* This function requires just one parameter, the miniflow name.
> +    /* A First optional paramter PMD thread ID can be also provided which
> +     * allows users to set miniflow implementation on a particular pmd.
> +     * The second paramter is the name of the function and if -pmd corr_id

parameter, core_id, name of the implementation.

> +     * is not provided this is the first paramter and only mandatory one.

parameter

> +     * The third and last one is the study-cnt which is only provided for
> +     * study function to set the packet count.
>       */
> -    const char *mfex_name = argv[1];
> +    const char *mfex_name = NULL;
>      struct shash_node *node;
> +    bool pmd_core_param_set = false;
> +    struct ds reply = DS_EMPTY_INITIALIZER;
> +
> +    if (strcmp("-pmd", argv[1]) == 0) {
> +        mfex_name = argv[3];
> +        pmd_core_param_set = true;
> +    } else {
> +        mfex_name = argv[1];
> +    }
> +
> +    uint32_t pmd_thread_specified = 0;

That is boolean

> +    uint32_t pmd_thread_to_change = 0;
> +    uint32_t pmd_thread_update_ok = 0;

Also boolean

> +
> +    if (pmd_core_param_set) {
> +        if (str_to_uint(argv[2], 10, &pmd_thread_to_change)) {
> +            pmd_thread_specified = 1;
> +        } else {
> +            /* argv[2] isn't even a uint. return without changing anything. */
> +            ds_put_format(&reply,
> +                 "Error: Miniflow parser not changed, PMD thread argument"
> +                 " passed is not valid: '%s'. Pass a valid pmd thread ID.\n",
> +                 argv[2]);
> +            const char *reply_str = ds_cstr(&reply);
> +            VLOG_INFO("%s", reply_str);
> +            unixctl_command_reply_error(conn, reply_str);
> +            ds_destroy(&reply);
> +            return;
> +        }
> +    }
>  
> -    ovs_mutex_lock(&dp_netdev_mutex);
>      int err = dp_mfex_impl_set_default_by_name(mfex_name);
>  
>      if (err) {
> -        ovs_mutex_unlock(&dp_netdev_mutex);
> -        struct ds reply = DS_EMPTY_INITIALIZER;
>          char *error_desc = NULL;
>          if (err == -EINVAL) {
>              error_desc = "Unknown miniflow extract implementation:";
> @@ -1106,6 +1138,66 @@ dpif_miniflow_extract_impl_set(struct unixctl_conn *conn, int argc,
>          return;
>      }
>  
> +    /* argv[4] is optional packet count, which user can provide along with
> +     * study function to set the minimum packet that must be matched in order
> +     * to choose the optimal function. */
> +    uint32_t pkt_cmp_count = 0;
> +    uint32_t study_ret = 0;
> +
> +    if (argc == 5) {
> +        if (str_to_uint(argv[4], 10, &pkt_cmp_count)) {
> +            study_ret = mfex_set_study_pkt_cnt(pkt_cmp_count, mfex_name);
> +
> +            if (study_ret == -EINVAL) {
> +                ds_put_format(&reply, "The study_pkt_cnt option is not valid"

The parameter is called study_cnt. 

> +                              " for the %s implementation.\n",
> +                              mfex_name);
> +                const char *reply_str = ds_cstr(&reply);
> +                unixctl_command_reply_error(conn, reply_str);
> +                VLOG_INFO("%s", reply_str);
> +                ds_destroy(&reply);
> +                return;
> +            }
> +        } else {
> +            ds_put_format(&reply, "Invalid study_pkt_cnt value: : %s.\n",
> +                          argv[4]);
> +            const char *reply_str = ds_cstr(&reply);
> +            unixctl_command_reply_error(conn, reply_str);
> +            VLOG_INFO("%s", reply_str);
> +            ds_destroy(&reply);
> +            return;
> +        }
> +    } else if ((!pmd_core_param_set) && (argc == 3)) {
> +        if (str_to_uint(argv[2], 10, &pkt_cmp_count)) {
> +            study_ret = mfex_set_study_pkt_cnt(pkt_cmp_count, mfex_name);
> +
> +            if (study_ret == -EINVAL) {
> +                ds_put_format(&reply, "The study_pkt_cnt option is not valid"
> +                              " for the %s implementation.\n",
> +                              mfex_name);
> +                const char *reply_str = ds_cstr(&reply);
> +                unixctl_command_reply_error(conn, reply_str);
> +                VLOG_INFO("%s", reply_str);
> +                ds_destroy(&reply);
> +                return;
> +            }
> +        } else {
> +            ds_put_format(&reply, "Invalid study_pkt_cnt value: %s.\n",
> +                          argv[2]);
> +            const char *reply_str = ds_cstr(&reply);
> +            unixctl_command_reply_error(conn, reply_str);
> +            VLOG_INFO("%s", reply_str);
> +            ds_destroy(&reply);
> +            return;
> +        }
> +    } else {
> +        /* Default packet compare count when packets count not provided. */
> +        study_ret = mfex_set_study_pkt_cnt(0, mfex_name);

Setting to zero returns an error. Should that be MFEX_MAX_COUNT?

> +
> +    }

Perhaps we could avoid repeating using the approach below:

    char *study_cnt_param = NULL;
    if (argc == 5) {
        study_cnt_param = argv[4];
    } else if ((!pmd_core_param_set) && (argc == 3)) {
        study_cnt_param = argv[2];
    } 

    if (study_cnt_param) {
        uint32_t pkt_cmp_count;

        if (str_to_uint(study_cnt_param, 10, &pkt_cmp_count)) {
            study_ret = mfex_set_study_pkt_cnt(pkt_cmp_count, mfex_name);
            [...]
        } else {
            [...]
        }
    } else {
        /* Default packet compare count when packets count not * provided. */
        study_ret = mfex_set_study_pkt_cnt(MFEX_MAX_PKT_COUNT, mfex_name); 
    }

> +
> +    ovs_mutex_lock(&dp_netdev_mutex);
> +
>      SHASH_FOR_EACH (node, &dp_netdevs) {
>          struct dp_netdev *dp = node->data;
>  
> @@ -1122,8 +1214,14 @@ dpif_miniflow_extract_impl_set(struct unixctl_conn *conn, int argc,
>                  continue;
>              }
>  
> +            if ((pmd_thread_specified) &&
> +                (pmd->core_id != pmd_thread_to_change)) {
> +                continue;
> +            }
> +
>              /* Initialize MFEX function pointer to the newly configured
>               * default. */
> +            pmd_thread_update_ok = 1;
>              atomic_uintptr_t *pmd_func = (void *) &pmd->miniflow_extract_opt;
>              atomic_store_relaxed(pmd_func, (uintptr_t) default_func);
>          };
> @@ -1131,9 +1229,30 @@ dpif_miniflow_extract_impl_set(struct unixctl_conn *conn, int argc,
>  
>      ovs_mutex_unlock(&dp_netdev_mutex);
>  
> +    /* If PMD thread was specified, but it wasn't found, return error. */
> +    if (pmd_thread_specified && !pmd_thread_update_ok) {
> +        ds_put_format(&reply,
> +             "Error: Miniflow parser not changed, PMD thread %d not in use,"
> +             " pass a valid pmd thread ID.\n",
> +             pmd_thread_to_change);
> +        const char *reply_str = ds_cstr(&reply);
> +        VLOG_INFO("%s", reply_str);
> +        unixctl_command_reply_error(conn, reply_str);
> +        ds_destroy(&reply);
> +        return;
> +    }
> +
>      /* Reply with success to command. */
> -    struct ds reply = DS_EMPTY_INITIALIZER;
> -    ds_put_format(&reply, "Miniflow implementation set to %s.\n", mfex_name);
> +    ds_put_format(&reply, "Miniflow implementation set to %s", mfex_name);
> +    if (pmd_thread_specified) {
> +        ds_put_format(&reply, ", on pmd thread %d", pmd_thread_to_change);
> +    }
> +    if (study_ret == 0) {
> +        ds_put_format(&reply, ", studying %d packets", pkt_cmp_count);
> +    }
> +
> +    ds_put_format(&reply, ".\n");
> +
>      const char *reply_str = ds_cstr(&reply);
>      VLOG_INFO("%s", reply_str);
>      unixctl_command_reply(conn, reply_str);
> @@ -1370,8 +1489,9 @@ dpif_netdev_init(void)
>                               0, 0, dpif_netdev_impl_get,
>                               NULL);
>      unixctl_command_register("dpif-netdev/miniflow-parser-set",
> -                             "miniflow_implementation_name",
> -                             1, 1, dpif_miniflow_extract_impl_set,
> +                             "[-pmd core] miniflow_implementation_name"
> +                             " [study_pkt_cnt]",
> +                             1, 5, dpif_miniflow_extract_impl_set,
>                               NULL);
>      unixctl_command_register("dpif-netdev/miniflow-parser-get", "",
>                               0, 0, dpif_miniflow_extract_impl_get,
> -- 
> 2.25.1
> 
> _______________________________________________
> dev mailing list
> dev at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev

-- 
fbl


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