dpif-netdev: Refactor generic implementation

This commit refactors the generic implementation. The
goal of this refactor is to simplify the code to enable
"specialization" of the functions at compile time.

Given compile-time optimizations, the compiler is able
to unroll loops, and create optimized code sequences due
to compile time knowledge of loop-trip counts.

In order to enable these compiler optimizations, we must
refactor the code to pass the loop-trip counts to functions
as compile time constants.

This patch allows the number of miniflow-bits set per "unit"
in the miniflow to be passed around as a function argument.

Note that this patch does NOT yet take advantage of doing so,
this is only a refactor to enable it in the next patches.

Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Tested-by: Malvika Gupta <malvika.gupta@arm.com>
Acked-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/dpif-netdev-private.h b/lib/dpif-netdev-private.h
index 555856482..610851a10 100644
--- a/lib/dpif-netdev-private.h
+++ b/lib/dpif-netdev-private.h
@@ -60,7 +60,7 @@ uint32_t (*dpcls_subtable_lookup_func)(struct dpcls_subtable *subtable,
                                        const struct netdev_flow_key *keys[],
                                        struct dpcls_rule **rules);
 
-/* Prototype for generic lookup func, using same code path as before. */
+/* Prototype for generic lookup func, using generic scalar code path. */
 uint32_t
 dpcls_subtable_lookup_generic(struct dpcls_subtable *subtable,
                               uint32_t keys_map,
@@ -77,12 +77,22 @@ struct dpcls_subtable {
     uint32_t hit_cnt;            /* Number of match hits in subtable in current
                                     optimization interval. */
 
+    /* Miniflow fingerprint that the subtable matches on. The miniflow "bits"
+     * are used to select the actual dpcls lookup implementation at subtable
+     * creation time.
+     */
+    uint8_t mf_bits_set_unit0;
+    uint8_t mf_bits_set_unit1;
+
     /* The lookup function to use for this subtable. If there is a known
      * property of the subtable (eg: only 3 bits of miniflow metadata is
      * used for the lookup) then this can point at an optimized version of
      * the lookup function for this particular subtable. */
     dpcls_subtable_lookup_func lookup_func;
 
+    /* Caches the masks to match a packet to, reducing runtime calculations. */
+    uint64_t *mf_masks;
+
     struct netdev_flow_key mask; /* Wildcards for fields (const). */
     /* 'mask' must be the last field, additional space is allocated here. */
 };