This patch adds predictable RSS API.
It is based on the idea of searching partial Toeplitz hash collisions.
Signed-off-by: Vladimir Medvedkin <vladimir.medved...@intel.com>
---
lib/librte_hash/meson.build | 3 +-
lib/librte_hash/rte_thash.c | 109 ++++++++++++++++++++++++
lib/librte_hash/rte_thash.h | 198 ++++++++++++++++++++++++++++++++++++++++++++
lib/librte_hash/version.map | 8 ++
4 files changed, 317 insertions(+), 1 deletion(-)
create mode 100644 lib/librte_hash/rte_thash.c
diff --git a/lib/librte_hash/meson.build b/lib/librte_hash/meson.build
index 242859f..3546014 100644
--- a/lib/librte_hash/meson.build
+++ b/lib/librte_hash/meson.build
@@ -8,6 +8,7 @@ headers = files('rte_fbk_hash.h',
'rte_thash.h')
indirect_headers += files('rte_crc_arm64.h')
-sources = files('rte_cuckoo_hash.c', 'rte_fbk_hash.c')
+sources = files('rte_cuckoo_hash.c', 'rte_fbk_hash.c', 'rte_thash.c')
+deps += ['net']
deps += ['ring']
deps += ['rcu']
diff --git a/lib/librte_hash/rte_thash.c b/lib/librte_hash/rte_thash.c
new file mode 100644
index 0000000..1325678
--- /dev/null
+++ b/lib/librte_hash/rte_thash.c
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2021 Intel Corporation
+ */
+
+#include <rte_thash.h>
+#include <rte_tailq.h>
+#include <rte_random.h>
+#include <rte_memcpy.h>
+#include <rte_errno.h>
+#include <rte_eal.h>
+#include <rte_eal_memconfig.h>
+#include <rte_malloc.h>
+
+#define THASH_NAME_LEN 64
+
+struct thash_lfsr {
+ uint32_t ref_cnt;
+ uint32_t poly;
+ /**< polynomial associated with the lfsr */
+ uint32_t rev_poly;
+ /**< polynomial to generate the sequence in reverse direction */
+ uint32_t state;
+ /**< current state of the lfsr */
+ uint32_t rev_state;
+ /**< current state of the lfsr for reverse direction */
+ uint32_t deg; /**< polynomial degree*/
+ uint32_t bits_cnt; /**< number of bits generated by lfsr*/
+};
+
+struct rte_thash_subtuple_helper {
+ char name[THASH_NAME_LEN]; /** < Name of subtuple configuration */
+ LIST_ENTRY(rte_thash_subtuple_helper) next;
+ struct thash_lfsr *lfsr;
+ uint32_t offset; /** < Offset of the m-sequence */
+ uint32_t len; /** < Length of the m-sequence */
+ uint32_t tuple_offset; /** < Offset in bits of the subtuple */
+ uint32_t tuple_len; /** < Length in bits of the subtuple */
+ uint32_t lsb_msk; /** < (1 << reta_sz_log) - 1 */
+ __extension__ uint32_t compl_table[0] __rte_cache_aligned;
+ /** < Complementary table */
+};
+
+struct rte_thash_ctx {
+ char name[THASH_NAME_LEN];
+ LIST_HEAD(, rte_thash_subtuple_helper) head;
+ uint32_t key_len; /** < Length of the NIC RSS hash key */
+ uint32_t reta_sz_log; /** < size of the RSS ReTa in bits */
+ uint32_t subtuples_nb; /** < number of subtuples */
+ uint32_t flags;
+ uint8_t hash_key[0];
+};
+
+struct rte_thash_ctx *
+rte_thash_init_ctx(const char *name __rte_unused,
+ uint32_t key_len __rte_unused, uint32_t reta_sz __rte_unused,
+ uint8_t *key __rte_unused, uint32_t flags __rte_unused)
+{
+ return NULL;
+}
+
+struct rte_thash_ctx *
+rte_thash_find_existing(const char *name __rte_unused)
+{
+ return NULL;
+}
+
+void
+rte_thash_free_ctx(struct rte_thash_ctx *ctx __rte_unused)
+{
+}
+
+int
+rte_thash_add_helper(struct rte_thash_ctx *ctx __rte_unused,
+ const char *name __rte_unused, uint32_t len __rte_unused,
+ uint32_t offset __rte_unused)
+{
+ return 0;
+}
+
+struct rte_thash_subtuple_helper *
+rte_thash_get_helper(struct rte_thash_ctx *ctx __rte_unused,
+ const char *name __rte_unused)
+{
+ return NULL;
+}
+
+uint32_t
+rte_thash_get_complement(struct rte_thash_subtuple_helper *h __rte_unused,
+ uint32_t hash __rte_unused, uint32_t desired_hash __rte_unused)
+{
+ return 0;
+}
+
+const uint8_t *
+rte_thash_get_key(struct rte_thash_ctx *ctx __rte_unused)
+{
+ return NULL;
+}
+
+int
+rte_thash_adjust_tuple(struct rte_thash_ctx *ctx __rte_unused,
+ struct rte_thash_subtuple_helper *h __rte_unused,
+ uint8_t *tuple __rte_unused, unsigned int tuple_len __rte_unused,
+ uint32_t desired_value __rte_unused,
+ unsigned int attempts __rte_unused,
+ rte_thash_check_tuple_t fn __rte_unused, void *userdata __rte_unused)
+{
+ return 0;
+}
diff --git a/lib/librte_hash/rte_thash.h b/lib/librte_hash/rte_thash.h
index 061efa2..f3e05fc 100644
--- a/lib/librte_hash/rte_thash.h
+++ b/lib/librte_hash/rte_thash.h
@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2015-2019 Vladimir Medvedkin <medvedk...@gmail.com>
+ * Copyright(c) 2021 Intel Corporation
*/
#ifndef _RTE_THASH_H
@@ -222,6 +223,203 @@ rte_softrss_be(uint32_t *input_tuple, uint32_t input_len,
return ret;
}
+/** @internal Minimum size of the RSS ReTa */
+#define RTE_THASH_RETA_SZ_MIN 2U
+/** @internal Maximum size of the RSS ReTa */
+#define RTE_THASH_RETA_SZ_MAX 16U
+
+/**
+ * LFSR will ignore if generated m-sequence has more than 2^n -1 bits
+ */
+#define RTE_THASH_IGNORE_PERIOD_OVERFLOW 0x1
+/**
+ * Generate minimal required bit (equal to ReTa LSB) sequence into
+ * the hash_key
+ */
+#define RTE_THASH_MINIMAL_SEQ 0x2
+
+/** @internal thash context structure. */
+struct rte_thash_ctx;
+/** @internal thash helper structure. */
+struct rte_thash_subtuple_helper;
+
+/**
+ * Create a new thash context.
+ *
+ * @param name
+ * Context name
+ * @param key_len
+ * Length of the toeplitz hash key
+ * @param reta_sz
+ * Logarithm of the NIC's Redirection Table (ReTa) size,
+ * i.e. number of the LSBs if the hash used to determine
+ * the reta entry.
+ * @param key
+ * Pointer to the key used to init an internal key state.
+ * Could be NULL, in this case internal key will be inited with random.
+ * @param flags
+ * Supported flags are:
+ * RTE_THASH_IGNORE_PERIOD_OVERFLOW
+ * RTE_THASH_MINIMAL_SEQ
+ * @return
+ * A pointer to the created context on success
+ * NULL otherwise
+ */
+__rte_experimental
+struct rte_thash_ctx *
+rte_thash_init_ctx(const char *name, uint32_t key_len, uint32_t reta_sz,
+ uint8_t *key, uint32_t flags);
+
+/**
+ * Find an existing thash context and return a pointer to it.
+ *
+ * @param name
+ * Name of the thash context
+ * @return
+ * Pointer to the thash context or NULL if it was not found with rte_errno
+ * set appropriately. Possible rte_errno values include:
+ * - ENOENT - required entry not available to return.
+ */
+__rte_experimental
+struct rte_thash_ctx *
+rte_thash_find_existing(const char *name);
+
+/**
+ * Free a thash context object
+ *
+ * @param ctx
+ * Thash context
+ * @return
+ * None
+ */
+__rte_experimental
+void
+rte_thash_free_ctx(struct rte_thash_ctx *ctx);
+
+/**
+ * Add a special properties to the toeplitz hash key inside a thash context.
+ * Creates an internal helper struct which has a complementary table
+ * to calculate toeplitz hash collisions.
+ * This function is not multi-thread safe.
+ *
+ * @param ctx
+ * Thash context
+ * @param name
+ * Name of the helper
+ * @param len
+ * Length in bits of the target subtuple
+ * Must be no shorter than reta_sz passed on rte_thash_init_ctx().
+ * @param offset
+ * Offset in bits of the subtuple
+ * @return
+ * 0 on success
+ * negative on error
+ */
+__rte_experimental
+int
+rte_thash_add_helper(struct rte_thash_ctx *ctx, const char *name, uint32_t len,
+ uint32_t offset);
+
+/**
+ * Find a helper in the context by the given name
+ *
+ * @param ctx
+ * Thash context
+ * @param name
+ * Name of the helper
+ * @return
+ * Pointer to the thash helper or NULL if it was not found.
+ */
+__rte_experimental
+struct rte_thash_subtuple_helper *
+rte_thash_get_helper(struct rte_thash_ctx *ctx, const char *name);
+
+/**
+ * Get a complementary value for the subtuple to produce a
+ * partial toeplitz hash collision. It must be XOR'ed with the
+ * subtuple to produce the hash value with the desired hash LSB's
+ * This function is multi-thread safe.
+ *
+ * @param h
+ * Pointer to the helper struct
+ * @param hash
+ * Toeplitz hash value calculated for the given tuple
+ * @param desired_hash
+ * Desired hash value to find a collision for
+ * @return
+ * A complementary value which must be xored with the corresponding subtuple
+ */
+__rte_experimental
+uint32_t
+rte_thash_get_complement(struct rte_thash_subtuple_helper *h,
+ uint32_t hash, uint32_t desired_hash);
+
+/**
+ * Get a pointer to the toeplitz hash contained in the context.
+ * It changes after each addition of a helper. It should be installed to
+ * the NIC.
+ *
+ * @param ctx
+ * Thash context
+ * @return
+ * A pointer to the toeplitz hash key
+ */
+__rte_experimental
+const uint8_t *
+rte_thash_get_key(struct rte_thash_ctx *ctx);
+
+/**
+ * Function prototype for the rte_thash_adjust_tuple
+ * to check if adjusted tuple could be used.
+ * Generally it is some kind of lookup function to check
+ * if adjusted tuple is already in use.
+ *
+ * @param userdata
+ * Pointer to the userdata. It could be a pointer to the
+ * table with used tuples to search.
+ * @param tuple
+ * Pointer to the tuple to check
+ *
+ * @return
+ * 1 on success
+ * 0 otherwise
+ */
+typedef int (*rte_thash_check_tuple_t)(void *userdata, uint8_t *tuple);
+
+/**
+ * Adjusts tuple in the way to make Toeplitz hash has
+ * desired least significant bits.
+ * This function is multi-thread safe.
+ *
+ * @param ctx
+ * Thash context
+ * @param h
+ * Pointer to the helper struct
+ * @param tuple
+ * Pointer to the tuple to be adjusted
+ * @param tuple_len
+ * Length of the tuple. Must be multiple of 4.
+ * @param desired_value
+ * Desired value of least significant bits of the hash
+ * @param attempts
+ * Number of attempts to adjust tuple with fn() calling
+ * @param fn
+ * Callback function to check adjusted tuple. Could be NULL
+ * @param userdata
+ * Pointer to the userdata to be passed to fn(). Could be NULL
+ *
+ * @return
+ * 0 on success
+ * negative otherwise
+ */
+__rte_experimental
+int
+rte_thash_adjust_tuple(struct rte_thash_ctx *ctx,
+ struct rte_thash_subtuple_helper *h,
+ uint8_t *tuple, unsigned int tuple_len,
+ uint32_t desired_value, unsigned int attempts,
+ rte_thash_check_tuple_t fn, void *userdata);
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/librte_hash/version.map b/lib/librte_hash/version.map
index c6d7308..17cb8aa 100644
--- a/lib/librte_hash/version.map
+++ b/lib/librte_hash/version.map
@@ -32,9 +32,17 @@ DPDK_21 {
EXPERIMENTAL {
global:
+ rte_thash_adjust_tuple;
rte_hash_free_key_with_position;
rte_hash_lookup_with_hash_bulk;
rte_hash_lookup_with_hash_bulk_data;
rte_hash_max_key_id;
rte_hash_rcu_qsbr_add;
+ rte_thash_add_helper;
+ rte_thash_find_existing;
+ rte_thash_free_ctx;
+ rte_thash_get_complement;
+ rte_thash_get_helper;
+ rte_thash_get_key;
+ rte_thash_init_ctx;
};
--
2.7.4
