[ovs-dev] [PATCH v2] ovn: Avoid nb_cfg update notification flooding

Anil Venkata anilvenkata at redhat.com
Fri Mar 23 06:12:51 UTC 2018


Is it possible to add a test for this patch i.e testing if hypervisors
correctly updating
Chassis_NB_Cfg's nb_cfg when a new value is assigned to NB_Global's nb_cfg?
Please see other comments inline

Thanks
Anil

On Thu, Mar 22, 2018 at 4:57 AM, Han Zhou <zhouhan at gmail.com> wrote:

> nb_cfg as a mechanism to "ping" OVN control plane is very useful
> in many ways. However, the current implementation will trigger
> update notifications flooding in the whole control plane. Each
> HV updates to SB the nb_cfg number and all these updates are
> notified to all the other HVs, which is O(n^2). Although updates
> are batched in fewers notifications than n^2, it still generates
> significant load on SB DB and also on ovn-controllers.
>
> To solve this problem and make the mechanism more useful in large
> scale producation deployment, this patch separates the per HV
> nb_cfg data in SB from the Chassis table to a separate table, so
> that each HV can conditionally monitor and get updates only for
> its own record.
>
> Test result shows great improvement:
> In a test environment with 1K sandbox HVs, and 10K ports created
> on 40 lswitches and 8 lrouters, do the sync test when the system
> is idle, with command:
>
>     time ovn-nbctl --wait=hv sync
>
> Original result:
> real    4m52.926s
> user    0m0.328s
> sys     0m0.004s
>
> With this patch:
> real    0m11.405s
> user    0m0.316s
> sys     0m0.016s
>
> Signed-off-by: Han Zhou <hzhou8 at ebay.com>
> ---
>
> Notes:
>     v1 -> v2:
>     - keep the old column in chassis table to avoid breaking upgrading
>     - avoid the attempt of adding redundant entry during startup
>
>  ovn/controller/chassis.c        | 35 ++++++++++++++++++++++++++++++++++-
>  ovn/controller/chassis.h        |  9 ++++++---
>  ovn/controller/ovn-controller.c | 21 ++++++++++++++++-----
>  ovn/northd/ovn-northd.c         | 21 ++++++++++++++++++---
>  ovn/ovn-sb.ovsschema            |  8 +++++++-
>  ovn/ovn-sb.xml                  | 26 ++++++++++++++++++++++----
>  6 files changed, 103 insertions(+), 17 deletions(-)
>
> diff --git a/ovn/controller/chassis.c b/ovn/controller/chassis.c
> index 6b5286a..6092dcc 100644
> --- a/ovn/controller/chassis.c
> +++ b/ovn/controller/chassis.c
> @@ -72,12 +72,28 @@ get_cms_options(const struct smap *ext_ids)
>      return smap_get_def(ext_ids, "ovn-cms-options", "");
>  }
>
> +static const struct sbrec_chassis_nb_cfg *
> +find_chassis_nb_cfg(struct ovsdb_idl *ovnsb_idl, const char *chassis_id)
> +{
> +    const struct sbrec_chassis_nb_cfg *chassis_nb_cfg_rec;
> +
> +    SBREC_CHASSIS_NB_CFG_FOR_EACH (chassis_nb_cfg_rec, ovnsb_idl) {
> +        if (!strcmp(chassis_nb_cfg_rec->chassis_name, chassis_id)) {
> +            break;
> +        }
> +    }
> +
> +    return chassis_nb_cfg_rec;
> +}
> +
>  /* Returns this chassis's Chassis record, if it is available and is
> currently
>   * amenable to a transaction. */
>  const struct sbrec_chassis *
>  chassis_run(struct controller_ctx *ctx, const char *chassis_id,
> -            const struct ovsrec_bridge *br_int)
> +            const struct ovsrec_bridge *br_int,
> +            const struct sbrec_chassis_nb_cfg **nb_cfg)
>  {
> +    *nb_cfg = NULL;
>      if (!ctx->ovnsb_idl_txn) {
>          return NULL;
>      }
> @@ -135,8 +151,17 @@ chassis_run(struct controller_ctx *ctx, const char
> *chassis_id,
>      ds_chomp(&iface_types, ',');
>      const char *iface_types_str = ds_cstr(&iface_types);
>
> +    const struct sbrec_chassis_nb_cfg *chassis_nb_cfg_rec
> +        = find_chassis_nb_cfg(ctx->ovnsb_idl, chassis_id);
> +    if (!chassis_nb_cfg_rec) {
> +        chassis_nb_cfg_rec = sbrec_chassis_nb_cfg_insert(
> ctx->ovnsb_idl_txn);
> +        sbrec_chassis_nb_cfg_set_chassis_name(chassis_nb_cfg_rec,
> chassis_id);
> +    }
> +    *nb_cfg = chassis_nb_cfg_rec;
> +
>

Can you please create this record after creation of chassis record i.e
move "sbrec_chassis_nb_cfg_insert" after
https://github.com/openvswitch/ovs/blob/master/ovn/controller/chassis.c#L223


>      const struct sbrec_chassis *chassis_rec
>          = get_chassis(ctx->ovnsb_idl, chassis_id);
> +
>      const char *encap_csum = smap_get_def(&cfg->external_ids,
>                                            "ovn-encap-csum", "true");
>      if (chassis_rec) {
> @@ -256,6 +281,14 @@ chassis_cleanup(struct controller_ctx *ctx,
>                                    "ovn-controller: unregistering chassis
> '%s'",
>                                    chassis_rec->name);
>          sbrec_chassis_delete(chassis_rec);
> +        const struct sbrec_chassis_nb_cfg *chassis_nb_cfg_rec
> +            = find_chassis_nb_cfg(ctx->ovnsb_idl, chassis_rec->name);
> +        if (chassis_nb_cfg_rec) {
> +            sbrec_chassis_nb_cfg_delete(chassis_nb_cfg_rec);
> +        } else {
> +            VLOG_WARN("Chassis_NB_Cfg record didn't exist for chassis
> '%s'",
> +                      chassis_rec->name);
> +        }
>      }
>      return false;
>  }
> diff --git a/ovn/controller/chassis.h b/ovn/controller/chassis.h
> index 2cc47fc..5ecf7f4 100644
> --- a/ovn/controller/chassis.h
> +++ b/ovn/controller/chassis.h
> @@ -17,6 +17,7 @@
>  #define OVN_CHASSIS_H 1
>
>  #include <stdbool.h>
> +#include "ovn/lib/ovn-sb-idl.h"
>
>  struct controller_ctx;
>  struct ovsdb_idl;
> @@ -24,9 +25,11 @@ struct ovsrec_bridge;
>  struct sbrec_chassis;
>
>  void chassis_register_ovs_idl(struct ovsdb_idl *);
> -const struct sbrec_chassis *chassis_run(struct controller_ctx *,
> -                                        const char *chassis_id,
> -                                        const struct ovsrec_bridge
> *br_int);
> +const struct sbrec_chassis *chassis_run(
> +            struct controller_ctx *,
> +            const char *chassis_id,
> +            const struct ovsrec_bridge *br_int,
> +            const struct sbrec_chassis_nb_cfg **nb_cfg);
>  bool chassis_cleanup(struct controller_ctx *, const struct sbrec_chassis
> *);
>
>  #endif /* ovn/chassis.h */
> diff --git a/ovn/controller/ovn-controller.c b/ovn/controller/ovn-
> controller.c
> index 7592bda..b2eb03b 100644
> --- a/ovn/controller/ovn-controller.c
> +++ b/ovn/controller/ovn-controller.c
> @@ -150,6 +150,7 @@ update_sb_monitors(struct ovsdb_idl *ovnsb_idl,
>      struct ovsdb_idl_condition mb = OVSDB_IDL_CONDITION_INIT(&mb);
>      struct ovsdb_idl_condition mg = OVSDB_IDL_CONDITION_INIT(&mg);
>      struct ovsdb_idl_condition dns = OVSDB_IDL_CONDITION_INIT(&dns);
> +    struct ovsdb_idl_condition nbcfg = OVSDB_IDL_CONDITION_INIT(&nbcfg);
>      sbrec_port_binding_add_clause_type(&pb, OVSDB_F_EQ, "patch");
>      /* XXX: We can optimize this, if we find a way to only monitor
>       * ports that have a Gateway_Chassis that point's to our own
> @@ -172,6 +173,12 @@ update_sb_monitors(struct ovsdb_idl *ovnsb_idl,
>          sbrec_port_binding_add_clause_options(&pb, OVSDB_F_INCLUDES,
> &l2);
>          const struct smap l3 = SMAP_CONST1(&l3, "l3gateway-chassis", id);
>          sbrec_port_binding_add_clause_options(&pb, OVSDB_F_INCLUDES,
> &l3);
> +
> +        /* Monitors Chassis_NB_Cfg record for current chassis only */
> +        sbrec_chassis_nb_cfg_add_clause_chassis_name(&nbcfg, OVSDB_F_EQ,
> +                                                     chassis->name);
> +    } else {
> +        ovsdb_idl_condition_add_clause_true(&nbcfg);
>      }
>      if (local_ifaces) {
>          const char *name;
> @@ -198,11 +205,13 @@ update_sb_monitors(struct ovsdb_idl *ovnsb_idl,
>      sbrec_mac_binding_set_condition(ovnsb_idl, &mb);
>      sbrec_multicast_group_set_condition(ovnsb_idl, &mg);
>      sbrec_dns_set_condition(ovnsb_idl, &dns);
> +    sbrec_chassis_nb_cfg_set_condition(ovnsb_idl, &nbcfg);
>      ovsdb_idl_condition_destroy(&pb);
>      ovsdb_idl_condition_destroy(&lf);
>      ovsdb_idl_condition_destroy(&mb);
>      ovsdb_idl_condition_destroy(&mg);
>      ovsdb_idl_condition_destroy(&dns);
> +    ovsdb_idl_condition_destroy(&nbcfg);
>  }
>
>  static const struct ovsrec_bridge *
> @@ -621,7 +630,7 @@ main(int argc, char *argv[])
>      create_ovnsb_indexes(ovnsb_idl_loop.idl);
>      lport_init(ovnsb_idl_loop.idl);
>
> -    ovsdb_idl_omit_alert(ovnsb_idl_loop.idl, &sbrec_chassis_col_nb_cfg);
> +    ovsdb_idl_omit_alert(ovnsb_idl_loop.idl,
> &sbrec_chassis_nb_cfg_col_nb_cfg);
>      update_sb_monitors(ovnsb_idl_loop.idl, NULL, NULL, NULL);
>      ovsdb_idl_get_initial_snapshot(ovnsb_idl_loop.idl);
>
> @@ -685,8 +694,9 @@ main(int argc, char *argv[])
>          chassis_index_init(&chassis_index, ctx.ovnsb_idl);
>
>          const struct sbrec_chassis *chassis = NULL;
> +        const struct sbrec_chassis_nb_cfg *chassis_nb_cfg = NULL;
>          if (chassis_id) {
> -            chassis = chassis_run(&ctx, chassis_id, br_int);
> +            chassis = chassis_run(&ctx, chassis_id, br_int,
> &chassis_nb_cfg);
>              encaps_run(&ctx, br_int, chassis_id);
>              bfd_calculate_active_tunnels(br_int, &active_tunnels);
>              binding_run(&ctx, br_int, chassis,
> @@ -730,10 +740,11 @@ main(int argc, char *argv[])
>
>                      hmap_destroy(&flow_table);
>                  }
> -                if (ctx.ovnsb_idl_txn) {
> +                if (ctx.ovnsb_idl_txn && chassis_nb_cfg) {
>                      int64_t cur_cfg = ofctrl_get_cur_cfg();
> -                    if (cur_cfg && cur_cfg != chassis->nb_cfg) {
> -                        sbrec_chassis_set_nb_cfg(chassis, cur_cfg);
> +                    if (cur_cfg && cur_cfg != chassis_nb_cfg->nb_cfg) {
> +                        sbrec_chassis_nb_cfg_set_nb_cfg(chassis_nb_cfg,
> +                                                        cur_cfg);
>                      }
>                  }
>              }
> diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
> index 3963810..9f4e0bc 100644
> --- a/ovn/northd/ovn-northd.c
> +++ b/ovn/northd/ovn-northd.c
> @@ -6483,6 +6483,11 @@ static const char *rbac_chassis_auth[] =
>  static const char *rbac_chassis_update[] =
>      {"nb_cfg", "external_ids", "encaps", "vtep_logical_switches"};
>
> +static const char *rbac_chassis_nb_cfg_auth[] =
> +    {"chassis_name"};
> +static const char *rbac_chassis_nb_cfg_update[] =
> +    {"nb_cfg"};
> +
>  static const char *rbac_encap_auth[] =
>      {"chassis_name"};
>  static const char *rbac_encap_update[] =
> @@ -6516,6 +6521,14 @@ static struct rbac_perm_cfg {
>          .n_update = ARRAY_SIZE(rbac_chassis_update),
>          .row = NULL
>      },{
> +        .table = "Chassis_NB_Cfg",
> +        .auth = rbac_chassis_nb_cfg_auth,
> +        .n_auth = ARRAY_SIZE(rbac_chassis_nb_cfg_auth),
> +        .insdel = true,
> +        .update = rbac_chassis_nb_cfg_update,
> +        .n_update = ARRAY_SIZE(rbac_chassis_nb_cfg_update),
> +        .row = NULL
> +    },{
>          .table = "Encap",
>          .auth = rbac_encap_auth,
>          .n_auth = ARRAY_SIZE(rbac_encap_auth),
> @@ -6676,9 +6689,9 @@ update_northbound_cfg(struct northd_context *ctx,
>      /* Update northbound hv_cfg if appropriate. */
>      if (nbg) {
>          /* Find minimum nb_cfg among all chassis. */
> -        const struct sbrec_chassis *chassis;
> +        const struct sbrec_chassis_nb_cfg *chassis;
>          int64_t hv_cfg = nbg->nb_cfg;
> -        SBREC_CHASSIS_FOR_EACH (chassis, ctx->ovnsb_idl) {
> +        SBREC_CHASSIS_NB_CFG_FOR_EACH (chassis, ctx->ovnsb_idl) {
>              if (chassis->nb_cfg < hv_cfg) {
>                  hv_cfg = chassis->nb_cfg;
>              }
> @@ -6911,9 +6924,11 @@ main(int argc, char *argv[])
>      add_column_noalert(ovnsb_idl_loop.idl, &sbrec_rbac_permission_col_
> update);
>
>      ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_chassis);
> -    ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_nb_cfg);
>      ovsdb_idl_add_column(ovnsb_idl_loop.idl, &sbrec_chassis_col_name);
>
> +    ovsdb_idl_add_table(ovnsb_idl_loop.idl, &sbrec_table_chassis_nb_cfg);
> +    ovsdb_idl_add_column(ovnsb_idl_loop.idl,
> &sbrec_chassis_nb_cfg_col_nb_cfg);
> +
>      /* Ensure that only a single ovn-northd is active in the deployment by
>       * acquiring a lock called "ovn_northd" on the southbound database
>       * and then only performing DB transactions if the lock is held. */
> diff --git a/ovn/ovn-sb.ovsschema b/ovn/ovn-sb.ovsschema
> index 2abcc6b..39be87d 100644
> --- a/ovn/ovn-sb.ovsschema
> +++ b/ovn/ovn-sb.ovsschema
> @@ -1,7 +1,7 @@
>  {
>      "name": "OVN_Southbound",
>      "version": "1.15.0",
> -    "cksum": "70426956 13327",
> +    "cksum": "1669322676 13561",
>      "tables": {
>          "SB_Global": {
>              "columns": {
> @@ -36,6 +36,12 @@
>                               "min": 0, "max": "unlimited"}}},
>              "isRoot": true,
>              "indexes": [["name"]]},
> +        "Chassis_NB_Cfg": {
> +            "columns": {
> +                "chassis_name": {"type": "string"},
>

Can we have chassis_id instead of chassis_name and add a reference to
chassis table,
like how Gateway_Chassis table is referencing Chassis table
https://github.com/openvswitch/ovs/blob/master/ovn/ovn-sb.ovsschema#L258



+                "nb_cfg": {"type": {"key": "integer"}}},
> +            "isRoot": true,
> +            "indexes": [["chassis_name"]]},
>          "Encap": {
>              "columns": {
>                  "type": {"type": {"key": {
> diff --git a/ovn/ovn-sb.xml b/ovn/ovn-sb.xml
> index 6a8b818..40e94b5 100644
> --- a/ovn/ovn-sb.xml
> +++ b/ovn/ovn-sb.xml
> @@ -212,10 +212,8 @@
>      </column>
>
>      <column name="nb_cfg">
> -      Sequence number for the configuration.  When
> <code>ovn-controller</code>
> -      updates the configuration of a chassis from the contents of the
> -      southbound database, it copies <ref table="SB_Global"
> column="nb_cfg"/>
> -      from the <ref table="SB_Global"/> table into this column.
> +      Deprecated. This column is replaced by the <ref
> table="Chassis_NB_Cfg"
> +      column="nb_cfg"/> column of the <ref table="Chassis_NB_Cfg"/> table.
>      </column>
>
>      <column name="external_ids" key="ovn-bridge-mappings">
> @@ -291,6 +289,26 @@
>      </group>
>    </table>
>
> +  <table name="Chassis_NB_Cfg" title="Chassis NB Config">
> +    <p>
> +      Each row in this table maintains the nb_cfg number that the
> corresponding
> +      chassis with <ref table="Chassis" column="name"/> in <ref
> table="Chassis"/>
> +      has processed. This information is stored in this separate table for
> +      performance considerations.
> +    </p>
> +
> +    <column name="nb_cfg">
> +      Sequence number for the configuration.  When
> <code>ovn-controller</code>
> +      updates the configuration of a chassis from the contents of the
> +      southbound database, it copies <ref table="SB_Global"
> column="nb_cfg"/>
> +      from the <ref table="SB_Global"/> table into this column.
> +    </column>
> +
> +    <column name="chassis_name">
> +      The name of the chassis that created this encap.
> +    </column>
> +  </table>
> +
>    <table name="Encap" title="Encapsulation Types">
>      <p>
>        The <ref column="encaps" table="Chassis"/> column in the <ref
> --
> 2.1.0
>
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