[ovs-dev] [threaded-put 14/21] ofproto-dpif-xlate: Add a mechanism to skip wildcard calculation.

[Ethan Jackson]

Btw to whoever reviews this, this version of the patch fails to
initialize skip_wildcards in xlate_in_init().

Ethan

On Sun, Dec 8, 2013 at 6:45 PM, Ethan Jackson <ethan at nicira.com> wrote:
> As time goes on and the classifier becomes more complicated, calculate
> the wildcard mask will get more and more expensive.  This patch adds a
> mechanism to xlate_actions() allowing callers to disable wildcard
> calculation when it isn't really necessary.  Used in future patches.
>
> Signed-off-by: Ethan Jackson <ethan at nicira.com>
> ---
>  ofproto/ofproto-dpif-xlate.c | 10 ++++++----
>  ofproto/ofproto-dpif-xlate.h |  6 ++++++
>  2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
> index da03f06..58ec484 100644
> --- a/ofproto/ofproto-dpif-xlate.c
> +++ b/ofproto/ofproto-dpif-xlate.c
> @@ -1870,9 +1870,10 @@ xlate_table_action(struct xlate_ctx *ctx,
>                     ofp_port_t in_port, uint8_t table_id, bool may_packet_in)
>  {
>      if (xlate_resubmit_resource_check(ctx)) {
> -        struct rule_dpif *rule;
>          ofp_port_t old_in_port = ctx->xin->flow.in_port.ofp_port;
> +        bool skip_wildcards = ctx->xin->skip_wildcards;
>          uint8_t old_table_id = ctx->table_id;
> +        struct rule_dpif *rule;
>
>          ctx->table_id = table_id;
>
> @@ -1880,8 +1881,8 @@ xlate_table_action(struct xlate_ctx *ctx,
>           * original input port (otherwise OFPP_NORMAL and OFPP_IN_PORT will
>           * have surprising behavior). */
>          ctx->xin->flow.in_port.ofp_port = in_port;
> -        rule_dpif_lookup_in_table(ctx->xbridge->ofproto,
> -                                  &ctx->xin->flow, &ctx->xout->wc,
> +        rule_dpif_lookup_in_table(ctx->xbridge->ofproto, &ctx->xin->flow,
> +                                  !skip_wildcards ? &ctx->xout->wc : NULL,
>                                    table_id, &rule);
>          ctx->xin->flow.in_port.ofp_port = old_in_port;
>
> @@ -3077,7 +3078,8 @@ xlate_actions__(struct xlate_in *xin, struct xlate_out *xout)
>      ctx.mpls_depth_delta = 0;
>
>      if (!xin->ofpacts && !ctx.rule) {
> -        rule_dpif_lookup(ctx.xbridge->ofproto, flow, wc, &rule);
> +        rule_dpif_lookup(ctx.xbridge->ofproto, flow,
> +                         !xin->skip_wildcards ? wc : NULL, &rule);
>          if (ctx.xin->resubmit_stats) {
>              rule_dpif_credit_stats(rule, ctx.xin->resubmit_stats);
>          }
> diff --git a/ofproto/ofproto-dpif-xlate.h b/ofproto/ofproto-dpif-xlate.h
> index f4ef1e1..68076ca 100644
> --- a/ofproto/ofproto-dpif-xlate.h
> +++ b/ofproto/ofproto-dpif-xlate.h
> @@ -73,6 +73,12 @@ struct xlate_in {
>       * not if we are just revalidating. */
>      bool may_learn;
>
> +    /* If the caller of xlate_actions() doesn't need the flow_wildcards
> +     * contained in struct xlate_out.  'skip_wildcards' can be set to true
> +     * disabling the expensive wildcard computation.  When true, 'wc' in struct
> +     * xlate_out is undefined and should not be read. */
> +    bool skip_wildcards;
> +
>      /* The rule initiating translation or NULL. If both 'rule' and 'ofpacts'
>       * are NULL, xlate_actions() will do the initial rule lookup itself. */
>      struct rule_dpif *rule;
> --
> 1.8.1.2
>