From: Vladimir Medvedkin <medvedkinv@gmail.com>
To: Yangchao Zhou <zhouyates@gmail.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] hash: optimize the softrss computation
Date: Tue, 22 Aug 2017 18:57:03 +0300 [thread overview]
Message-ID: <CANDrEHk6oz5ebCOE2BrCoUWKgQLVLP3_298JBSLe2=7zCetP2w@mail.gmail.com> (raw)
In-Reply-To: <1503403355-4917-1-git-send-email-zhouyates@gmail.com>
Hi,
2017-08-22 15:02 GMT+03:00 Yangchao Zhou <zhouyates@gmail.com>:
> Use rte_bsf32 and fast bit unset operation to optimize the softrss
> computation.
> The following measurements shows improvement over the default
> softrss computation function.
>
> tuple lens old(cycles) new(cycles)
> 3 1225 337
> 9 3743 992
>
> Signed-off-by: Yangchao Zhou <zhouyates@gmail.com>
> ---
> lib/librte_hash/rte_thash.h | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/lib/librte_hash/rte_thash.h b/lib/librte_hash/rte_thash.h
> index 2fffd61..4fa5e07 100644
> --- a/lib/librte_hash/rte_thash.h
> +++ b/lib/librte_hash/rte_thash.h
> @@ -207,15 +207,14 @@ static inline uint32_t
> rte_softrss(uint32_t *input_tuple, uint32_t input_len,
> const uint8_t *rss_key)
> {
> - uint32_t i, j, ret = 0;
> + uint32_t i, j, map, ret = 0;
>
> for (j = 0; j < input_len; j++) {
> - for (i = 0; i < 32; i++) {
> - if (input_tuple[j] & (1 << (31 - i))) {
> - ret ^= rte_cpu_to_be_32(((const uint32_t
> *)rss_key)[j]) << i |
> + for (map = input_tuple[j]; map; map &= (map - 1)) {
> + i = rte_bsf32(map);
> + ret ^= rte_cpu_to_be_32(((const uint32_t
> *)rss_key)[j]) << (31 - i) |
> (uint32_t)((uint64_t)(rte_cpu_to_be_32(((const
> uint32_t *)rss_key)[j + 1])) >>
> - (32 - i));
> - }
> + (i + 1));
> }
> }
> return ret;
> @@ -238,14 +237,13 @@ static inline uint32_t
> rte_softrss_be(uint32_t *input_tuple, uint32_t input_len,
> const uint8_t *rss_key)
> {
> - uint32_t i, j, ret = 0;
> + uint32_t i, j, map, ret = 0;
>
> for (j = 0; j < input_len; j++) {
> - for (i = 0; i < 32; i++) {
> - if (input_tuple[j] & (1 << (31 - i))) {
> - ret ^= ((const uint32_t *)rss_key)[j] << i
> |
> - (uint32_t)((uint64_t)(((const
> uint32_t *)rss_key)[j + 1]) >> (32 - i));
> - }
> + for (map = input_tuple[j]; map; map &= (map - 1)) {
> + i = rte_bsf32(map);
> + ret ^= ((const uint32_t *)rss_key)[j] << (31 - i) |
> + (uint32_t)((uint64_t)(((const uint32_t
> *)rss_key)[j + 1]) >> (i + 1));
> }
> }
> return ret;
> --
> 2.7.4
>
>
Looks good for me. Thanks!
Reviewed-by: Medvedkin Vladimir <medvedkinv@gmail.com>
--
Regards,
Vladimir
next prev parent reply other threads:[~2017-08-22 15:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-22 12:02 Yangchao Zhou
2017-08-22 15:57 ` Vladimir Medvedkin [this message]
2017-09-22 15:33 ` De Lara Guarch, Pablo
2017-10-06 22:31 ` Thomas Monjalon
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