Looks good, thanks!
Acked-by: Jarno Rajahalme <jrajaha...@nicira.com>
& pushed to master,
Jarno
On Sep 5, 2014, at 5:10 PM, Daniele Di Proietto <ddiproie...@vmware.com> wrote:
> netdev_flow_key is a miniflow with the following constraints:
>
> 1) It is used only inside dpif-netdev.c.
> 2) It always has inline values.
> 3) It contains only miniflows created by miniflow_extract().
>
> Therefore, by using these new functions instead of the miniflow_* ones, we get
> the following (performance related) benefits:
>
> - Because of (1) the functions can be inlined.
> - Because of (2) and (3) the netdev_flow_key can be treated as POD.
> Specifically, because of (3), we can do comparisons with memcmp, since if the
> map is different the miniflow must be different.
>
> Signed-off-by: Daniele Di Proietto <ddiproie...@vmware.com>
> ---
> lib/dpif-netdev.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 62 insertions(+), 6 deletions(-)
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 869fb55..112cd5a 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -87,7 +87,7 @@ static struct shash dp_netdevs
> OVS_GUARDED_BY(dp_netdev_mutex)
>
> static struct vlog_rate_limit upcall_rl = VLOG_RATE_LIMIT_INIT(600, 600);
>
> -/* Stores a miniflow */
> +/* Stores a miniflow with inline values */
>
> /* There are fields in the flow structure that we never use. Therefore we can
> * save a few words of memory */
> @@ -1133,6 +1133,59 @@ static bool dp_netdev_flow_ref(struct dp_netdev_flow
> *flow)
> return ovs_refcount_try_ref_rcu(&flow->ref_cnt);
> }
>
> +/* netdev_flow_key utilities.
> + *
> + * netdev_flow_key is basically a miniflow. We use these functions
> + * (netdev_flow_key_clone, netdev_flow_key_equal, ...) instead of the
> miniflow
> + * functions (miniflow_clone_inline, miniflow_equal, ...), because:
> + *
> + * - Since we are dealing exclusively with miniflows created by
> + * miniflow_extract(), if the map is different the miniflow is different.
> + * Therefore we can be faster by comparing the map and the miniflow in a
> + * single memcmp().
> + * _ netdev_flow_key's miniflow has always inline values.
> + * - These functions can be inlined by the compiler.
> + *
> + * The following assertions make sure that what we're doing with miniflow is
> + * safe
> + */
> +BUILD_ASSERT_DECL(offsetof(struct miniflow, inline_values)
> + == sizeof(uint64_t));
> +BUILD_ASSERT_DECL(offsetof(struct netdev_flow_key, flow) == 0);
> +
> +static inline struct netdev_flow_key *
> +miniflow_to_netdev_flow_key(const struct miniflow *mf)
> +{
> + return (struct netdev_flow_key *) CONST_CAST(struct miniflow *, mf);
> +}
> +
> +/* Given the number of bits set in the miniflow map, returns the size of the
> + * netdev_flow key */
> +static inline uint32_t
> +netdev_flow_key_size(uint32_t flow_u32s)
> +{
> + return MINIFLOW_VALUES_SIZE(flow_u32s)
> + + offsetof(struct miniflow, inline_values);
> +}
> +
> +/* Used to compare 'netdev_flow_key's (miniflows) in the exact match cache.
> */
> +static inline bool
> +netdev_flow_key_equal(const struct netdev_flow_key *a,
> + const struct netdev_flow_key *b)
> +{
> + uint32_t size = count_1bits(a->flow.map);
> +
> + return !memcmp(a, b, netdev_flow_key_size(size));
> +}
> +
> +static inline void
> +netdev_flow_key_clone(struct netdev_flow_key *dst,
> + const struct netdev_flow_key *src,
> + uint32_t size)
> +{
> + memcpy(dst, src, netdev_flow_key_size(size));
> +}
> +
> static inline bool
> emc_entry_alive(struct emc_entry *ce)
> {
> @@ -1150,7 +1203,7 @@ emc_clear_entry(struct emc_entry *ce)
>
> static inline void
> emc_change_entry(struct emc_entry *ce, struct dp_netdev_flow *flow,
> - const struct miniflow *mf, uint32_t hash)
> + const struct netdev_flow_key *mf, uint32_t hash)
> {
> if (ce->flow != flow) {
> if (ce->flow) {
> @@ -1164,7 +1217,7 @@ emc_change_entry(struct emc_entry *ce, struct
> dp_netdev_flow *flow,
> }
> }
> if (mf) {
> - miniflow_clone_inline(&ce->mf.flow, mf, count_1bits(mf->map));
> + netdev_flow_key_clone(&ce->mf, mf, count_1bits(mf->flow.map));
> ce->hash = hash;
> }
> }
> @@ -1178,7 +1231,8 @@ emc_insert(struct emc_cache *cache, const struct
> miniflow *mf, uint32_t hash,
>
> EMC_FOR_EACH_POS_WITH_HASH(cache, current_entry, hash) {
> if (current_entry->hash == hash
> - && miniflow_equal(¤t_entry->mf.flow, mf)) {
> + && netdev_flow_key_equal(¤t_entry->mf,
> + miniflow_to_netdev_flow_key(mf))) {
>
> /* We found the entry with the 'mf' miniflow */
> emc_change_entry(current_entry, flow, NULL, 0);
> @@ -1197,7 +1251,8 @@ emc_insert(struct emc_cache *cache, const struct
> miniflow *mf, uint32_t hash,
> /* We didn't find the miniflow in the cache.
> * The 'to_be_replaced' entry is where the new flow will be stored */
>
> - emc_change_entry(to_be_replaced, flow, mf, hash);
> + emc_change_entry(to_be_replaced, flow, miniflow_to_netdev_flow_key(mf),
> + hash);
> }
>
> static inline struct dp_netdev_flow *
> @@ -1207,7 +1262,8 @@ emc_lookup(struct emc_cache *cache, const struct
> miniflow *mf, uint32_t hash)
>
> EMC_FOR_EACH_POS_WITH_HASH(cache, current_entry, hash) {
> if (current_entry->hash == hash && emc_entry_alive(current_entry)
> - && miniflow_equal(¤t_entry->mf.flow, mf)) {
> + && netdev_flow_key_equal(¤t_entry->mf,
> + miniflow_to_netdev_flow_key(mf))) {
>
> /* We found the entry with the 'mf' miniflow */
> return current_entry->flow;
> --
> 2.1.0.rc1
>
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