netdev - [PATCH net-next 7/7] tcp: cdg: use tcp high resolution clock cache

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Message-Id: <20181015163758.232436-8-edumazet@google.com>
Date:   Mon, 15 Oct 2018 09:37:58 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Neal Cardwell <ncardwell@...gle.com>,
        Yuchung Cheng <ycheng@...gle.com>,
        Soheil Hassas Yeganeh <soheil@...gle.com>,
        Gasper Zejn <zelo.zejn@...il.com>
Cc:     netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 7/7] tcp: cdg: use tcp high resolution clock cache

We store in tcp socket a cache of most recent high resolution
clock, there is no need to call local_clock() again, since
this cache is good enough.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/tcp_cdg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_cdg.c b/net/ipv4/tcp_cdg.c
index 06fbe102a425f28b43294925d8d13af4a13ec776..37eebd9103961be4731323cfb4d933b51954e802 100644
--- a/net/ipv4/tcp_cdg.c
+++ b/net/ipv4/tcp_cdg.c
@@ -146,7 +146,7 @@ static void tcp_cdg_hystart_update(struct sock *sk)
 		return;
 
 	if (hystart_detect & HYSTART_ACK_TRAIN) {
-		u32 now_us = div_u64(local_clock(), NSEC_PER_USEC);
+		u32 now_us = tp->tcp_mstamp;
 
 		if (ca->last_ack == 0 || !tcp_is_cwnd_limited(sk)) {
 			ca->last_ack = now_us;
-- 
2.19.0.605.g01d371f741-goog