[dpdk-dev] [PATCH 2/5] hash: enable gfni thash implementation
Medvedkin, Vladimir
vladimir.medvedkin at intel.com
Fri Oct 15 11:13:55 CEST 2021
Hi Konstantin,
On 08/10/2021 13:31, Ananyev, Konstantin wrote:
>
>> This patch enables new GFNI Toeplitz hash in
>> predictable RSS library.
>>
>> Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin at intel.com>
>> ---
>> lib/hash/rte_thash.c | 43 +++++++++++++++++++++++++++++++++++++++----
>> lib/hash/rte_thash.h | 19 +++++++++++++++++++
>> lib/hash/version.map | 1 +
>> 3 files changed, 59 insertions(+), 4 deletions(-)
>>
>> diff --git a/lib/hash/rte_thash.c b/lib/hash/rte_thash.c
>> index 07447f7..86a0e96 100644
>> --- a/lib/hash/rte_thash.c
>> +++ b/lib/hash/rte_thash.c
>> @@ -86,6 +86,8 @@ struct rte_thash_ctx {
>> uint32_t reta_sz_log; /** < size of the RSS ReTa in bits */
>> uint32_t subtuples_nb; /** < number of subtuples */
>> uint32_t flags;
>> + uint64_t *matrices;
>
> Comment, what is that, etc.
>
I'll rephrase the comment below.
>> + /**< rte_thash_complete_matrix generated matrices */
>> uint8_t hash_key[0];
>> };
>>
>> @@ -253,12 +255,25 @@ rte_thash_init_ctx(const char *name, uint32_t key_len, uint32_t reta_sz,
>> ctx->hash_key[i] = rte_rand();
>> }
>>
>> + if (rte_thash_gfni_supported) {
>
> I think it should be:
> if (rte_thash_gfni_supported && rte_vect_get_max_simd_bitwidth() >= RTE_VECT_SIMD_512)
>
>
Agree
>> + ctx->matrices = rte_zmalloc(NULL, key_len * sizeof(uint64_t),
>> + RTE_CACHE_LINE_SIZE);
>
> You can do it probably before allocation ctx, at the same place where te is allocated.
> Might be a bit nicer.
>
I'd prefer to keep allocation and initialization of matrices in one
place, below there is rte_thash_complete_matrix() which uses previously
generated ctx->hash_key.
>> + if (ctx->matrices == NULL)
>
> RTE_LOG(ERR, ...);
> rte_ernno = ENOMEM;
>
Agree
>> + goto free_ctx;
>> +
>> + rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
>> + key_len);
>> + }
>> +
>> te->data = (void *)ctx;
>> TAILQ_INSERT_TAIL(thash_list, te, next);
>>
>> rte_mcfg_tailq_write_unlock();
>>
>> return ctx;
>> +
>> +free_ctx:
>> + rte_free(ctx);
>> free_te:
>> rte_free(te);
>> exit:
>> @@ -372,6 +387,10 @@ generate_subkey(struct rte_thash_ctx *ctx, struct thash_lfsr *lfsr,
>> set_bit(ctx->hash_key, get_rev_bit_lfsr(lfsr), i);
>> }
>>
>> + if (rte_thash_gfni_supported)
>
> Here and in data-path functions, I think it would be better:
> if (ctx->matrices != NULL)
Agree
>> + rte_thash_complete_matrix(ctx->matrices, ctx->hash_key,
>> + ctx->key_len);
>> +
>> return 0;
>> }
>>
>> @@ -628,6 +647,16 @@ rte_thash_get_key(struct rte_thash_ctx *ctx)
>> return ctx->hash_key;
>> }
>>
>> +const uint64_t *
>> +rte_thash_get_gfni_matrices(struct rte_thash_ctx *ctx)
>> +{
>> + if (rte_thash_gfni_supported)
>> + return ctx->matrices;
>
> Why not just always:
> return ctx->matices;
> ?
>
Agree
>> +
>> + rte_errno = ENOTSUP;
>> + return NULL;
>> +}
>> +
>> static inline uint8_t
>> read_unaligned_byte(uint8_t *ptr, unsigned int len, unsigned int offset)
>> {
>> @@ -739,11 +768,17 @@ rte_thash_adjust_tuple(struct rte_thash_ctx *ctx,
>> attempts = RTE_MIN(attempts, 1U << (h->tuple_len - ctx->reta_sz_log));
>>
>> for (i = 0; i < attempts; i++) {
>> - for (j = 0; j < (tuple_len / 4); j++)
>> - tmp_tuple[j] =
>> - rte_be_to_cpu_32(*(uint32_t *)&tuple[j * 4]);
>> + if (rte_thash_gfni_supported)
> if (ctx->matrices)
>
>> + hash = rte_thash_gfni(ctx->matrices, tuple, tuple_len);
>> + else {
>> + for (j = 0; j < (tuple_len / 4); j++)
>> + tmp_tuple[j] =
>> + rte_be_to_cpu_32(
>> + *(uint32_t *)&tuple[j * 4]);
>> +
>> + hash = rte_softrss(tmp_tuple, tuple_len / 4, hash_key);
>> + }
>>
>> - hash = rte_softrss(tmp_tuple, tuple_len / 4, hash_key);
>> adj_bits = rte_thash_get_complement(h, hash, desired_value);
>>
>> /*
>> diff --git a/lib/hash/rte_thash.h b/lib/hash/rte_thash.h
>> index e3f1fc6..6e6861c 100644
>> --- a/lib/hash/rte_thash.h
>> +++ b/lib/hash/rte_thash.h
>> @@ -410,6 +410,25 @@ const uint8_t *
>> rte_thash_get_key(struct rte_thash_ctx *ctx);
>>
>> /**
>> + * Get a pointer to the toeplitz hash matrices contained in the context.
>> + * These matrices could be used with fast toeplitz hash implementation if
>> + * CPU supports GFNI.
>> + * Matrices changes after each addition of a helper.
>> + *
>> + * @warning
>> + * @b EXPERIMENTAL: this API may change without prior notice.
>> + *
>> + * @param ctx
>> + * Thash context
>> + * @return
>> + * A pointer to the toeplitz hash key matrices on success
>> + * NULL if GFNI is not supported.
>> + */
>> +__rte_experimental
>> +const uint64_t *
>> +rte_thash_get_gfni_matrices(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
>> diff --git a/lib/hash/version.map b/lib/hash/version.map
>> index cecf922..3eda695 100644
>> --- a/lib/hash/version.map
>> +++ b/lib/hash/version.map
>> @@ -43,6 +43,7 @@ EXPERIMENTAL {
>> rte_thash_find_existing;
>> rte_thash_free_ctx;
>> rte_thash_get_complement;
>> + rte_thash_get_gfni_matrices;
>> rte_thash_get_helper;
>> rte_thash_get_key;
>> rte_thash_gfni_supported;
>> --
>> 2.7.4
>
--
Regards,
Vladimir
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