On Tue, Apr 30, 2024 at 6:28 PM Yoan Picchi <yoan.pic...@arm.com> wrote:
>
> Current hitmask includes padding due to Intel's SIMD
> implementation detail. This patch allows non Intel SIMD
> implementations to benefit from a dense hitmask.
> In addition, the new dense hitmask interweave the primary
> and secondary matches which allow a better cache usage and
> enable future improvements for the SIMD implementations
> The default non SIMD path now use this dense mask.
>
> Signed-off-by: Yoan Picchi <yoan.pic...@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> Reviewed-by: Nathan Brown <nathan.br...@arm.com>
> ---
> .mailmap | 2 +
> lib/hash/arch/arm/compare_signatures.h | 61 +++++++
> lib/hash/arch/common/compare_signatures.h | 37 +++++
> lib/hash/arch/x86/compare_signatures.h | 53 ++++++
> lib/hash/rte_cuckoo_hash.c | 192 ++++++++++++----------
> 5 files changed, 254 insertions(+), 91 deletions(-)
> create mode 100644 lib/hash/arch/arm/compare_signatures.h
> create mode 100644 lib/hash/arch/common/compare_signatures.h
> create mode 100644 lib/hash/arch/x86/compare_signatures.h
>
> diff --git a/.mailmap b/.mailmap
> index 66ebc20666..00b50414d3 100644
> --- a/.mailmap
> +++ b/.mailmap
> @@ -494,6 +494,7 @@ Hari Kumar Vemula <hari.kumarx.vem...@intel.com>
> Harini Ramakrishnan <harini.ramakrish...@microsoft.com>
> Hariprasad Govindharajan <hariprasad.govindhara...@intel.com>
> Harish Patil <harish.pa...@cavium.com> <harish.pa...@qlogic.com>
> +Harjot Singh <harjot.si...@arm.com>
This should be in patch 3.
> Harman Kalra <hka...@marvell.com>
> Harneet Singh <harneet.si...@intel.com>
> Harold Huang <baymaxhu...@gmail.com>
> @@ -1633,6 +1634,7 @@ Yixue Wang <yixue.w...@intel.com>
> Yi Yang <yangy...@inspur.com> <yi.y.y...@intel.com>
> Yi Zhang <zhang.y...@zte.com.cn>
> Yoann Desmouceaux <ydesm...@cisco.com>
> +Yoan Picchi <yoan.pic...@arm.com>
> Yogesh Jangra <yogesh.jan...@intel.com>
> Yogev Chaimovich <yo...@cgstowernetworks.com>
> Yongjie Gu <yongjiex...@intel.com>
> diff --git a/lib/hash/arch/arm/compare_signatures.h
> b/lib/hash/arch/arm/compare_signatures.h
> new file mode 100644
> index 0000000000..46d15da89f
> --- /dev/null
> +++ b/lib/hash/arch/arm/compare_signatures.h
Why create a new directory?
Simple lib/hash/hash_compare_signature_{arm,x86,generic}.h are enough.
> @@ -0,0 +1,61 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2010-2016 Intel Corporation
> + * Copyright(c) 2018-2024 Arm Limited
> + */
> +
> +/*
> + * Arm's version uses a densely packed hitmask buffer:
> + * Every bit is in use.
> + */
> +
> +#include <inttypes.h>
> +#include <rte_common.h>
> +#include <rte_vect.h>
> +#include "rte_cuckoo_hash.h"
Please separate headers by groups, like in
https://doc.dpdk.org/guides/contributing/coding_style.html#header-includes
> +
> +#define DENSE_HASH_BULK_LOOKUP 1
> +
> +static inline void
> +compare_signatures_dense(uint16_t *hitmask_buffer,
> + const uint16_t *prim_bucket_sigs,
> + const uint16_t *sec_bucket_sigs,
> + uint16_t sig,
> + enum rte_hash_sig_compare_function sig_cmp_fn)
Strange indent.
> +{
> +
> + static_assert(sizeof(*hitmask_buffer) >= 2 * (RTE_HASH_BUCKET_ENTRIES
> / 8),
> + "hitmask_buffer must be wide enough to fit
> a dense hitmask");
This is similar but less strict than an added check in
rte_cuckoo_hash.c later in this patch.
So I suspect only one of those checks is necessary.
But I don't understand the logic, so for you to figure out :-).
> +
> + /* For match mask every bits indicates the match */
> + switch (sig_cmp_fn) {
> +#if RTE_HASH_BUCKET_ENTRIES <= 8
> + case RTE_HASH_COMPARE_NEON: {
> + uint16x8_t vmat, vsig, x;
> + int16x8_t shift = {0, 1, 2, 3, 4, 5, 6, 7};
> + uint16_t low, high;
> +
> + vsig = vld1q_dup_u16((uint16_t const *)&sig);
> + /* Compare all signatures in the primary bucket */
> + vmat = vceqq_u16(vsig,
> + vld1q_u16((uint16_t const *)prim_bucket_sigs));
General comment for this series.
When possible, keep on the same line up to 100 chars, the code is hard
enough to read with all those vector intrinsics...
> + x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x0001)), shift);
> + low = (uint16_t)(vaddvq_u16(x));
> + /* Compare all signatures in the secondary bucket */
> + vmat = vceqq_u16(vsig,
> + vld1q_u16((uint16_t const *)sec_bucket_sigs));
> + x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x0001)), shift);
> + high = (uint16_t)(vaddvq_u16(x));
> + *hitmask_buffer = low | high << RTE_HASH_BUCKET_ENTRIES;
> +
> + }
> + break;
> +#endif
> + default:
> + for (unsigned int i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
> + *hitmask_buffer |=
> + (sig == prim_bucket_sigs[i]) << i;
> + *hitmask_buffer |=
> + ((sig == sec_bucket_sigs[i]) << i) <<
> RTE_HASH_BUCKET_ENTRIES;
> + }
> + }
> +}
[snip]
--
David Marchand
