net/sfc: use even spread mode in flow action RSS

If the user provides contiguous ascending queue IDs,
use the even spread mode to avoid wasting resources
which are needed to serve indirection table entries.

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>

diff --git a/drivers/net/sfc/sfc_flow_rss.c b/drivers/net/sfc/sfc_flow_rss.c
index 4bf300216406381cff444110b013149ce7b6b64c..e28c943335f3b05d5cf853a050f78c3de5804fcb 100644 (file)
--- a/drivers/net/sfc/sfc_flow_rss.c
+++ b/drivers/net/sfc/sfc_flow_rss.c
@@ -140,6 +140,8 @@ sfc_flow_rss_parse_conf(struct sfc_adapter *sa,
                return EINVAL;
        }
 
+       out->rte_hash_function = in->func;
+
        if (in->queue_num == 0) {
                sfc_err(sa, "flow-rss: parse: 'queue_num' is 0; MIN=1");
                return EINVAL;
@@ -317,6 +319,9 @@ sfc_flow_rss_ctx_program_tbl(struct sfc_adapter *sa,
 
        SFC_ASSERT(sfc_adapter_is_locked(sa));
 
+       if (nb_tbl_entries == 0)
+               return 0;
+
        if (conf->nb_qid_offsets != 0) {
                SFC_ASSERT(ctx->qid_offsets != NULL);
 
@@ -336,6 +341,7 @@ sfc_flow_rss_ctx_program(struct sfc_adapter *sa, struct sfc_flow_rss_ctx *ctx)
 {
        efx_rx_scale_context_type_t ctx_type = EFX_RX_SCALE_EXCLUSIVE;
        struct sfc_adapter_shared * const sas = sfc_sa2shared(sa);
+       const efx_nic_cfg_t *encp = efx_nic_cfg_get(sa->nic);
        const struct sfc_flow_rss *flow_rss = &sa->flow_rss;
        struct sfc_rss *ethdev_rss = &sas->rss;
        struct sfc_flow_rss_conf *conf;
@@ -366,6 +372,19 @@ sfc_flow_rss_ctx_program(struct sfc_adapter *sa, struct sfc_flow_rss_ctx *ctx)
 
        nb_tbl_entries = RTE_MAX(flow_rss->nb_tbl_entries_min, nb_qid_offsets);
 
+       if (conf->rte_hash_function == RTE_ETH_HASH_FUNCTION_DEFAULT &&
+           conf->nb_qid_offsets == 0 &&
+           conf->qid_span <= encp->enc_rx_scale_even_spread_max_nqueues) {
+               /*
+                * Conformance to a specific hash algorithm is a don't care to
+                * the user. The queue array is contiguous and ascending. That
+                * means that the even spread context may be requested here in
+                * order to avoid wasting precious indirection table resources.
+                */
+               ctx_type = EFX_RX_SCALE_EVEN_SPREAD;
+               nb_tbl_entries = 0;
+       }
+
        if (ctx->nic_handle_refcnt == 0) {
                rc = efx_rx_scale_context_alloc_v2(sa->nic, ctx_type,
                                                   conf->qid_span,

diff --git a/drivers/net/sfc/sfc_flow_rss.h b/drivers/net/sfc/sfc_flow_rss.h
index 3341d06cf474f69eac1fcf0d9345c111e07c23bb..2ed81dc19007a2ac016e40f76edc5524bebdd6f0 100644 (file)
--- a/drivers/net/sfc/sfc_flow_rss.h
+++ b/drivers/net/sfc/sfc_flow_rss.h
@@ -20,6 +20,7 @@ extern "C" {
 
 struct sfc_flow_rss_conf {
        uint8_t                         key[EFX_RSS_KEY_SIZE];
+       enum rte_eth_hash_function      rte_hash_function;
        efx_rx_hash_type_t              efx_hash_types;
        unsigned int                    nb_qid_offsets;
        unsigned int                    qid_span;