From: Yangchao Zhou <zhouyates@gmail.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH] hash: optimize the softrss computation
Date: Tue, 22 Aug 2017 20:02:35 +0800 [thread overview]
Message-ID: <1503403355-4917-1-git-send-email-zhouyates@gmail.com> (raw)
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
next reply other threads:[~2017-08-22 12:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-22 12:02 Yangchao Zhou [this message]
2017-08-22 15:57 ` Vladimir Medvedkin
2017-09-22 15:33 ` De Lara Guarch, Pablo
2017-10-06 22:31 ` Thomas Monjalon
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