Commit 991a26af authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by David S. Miller
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tcp_nv: use do_div() instead of expensive div64_u64() 



Average RTT is 32-bit thus full 64-bit division is redundant.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9d917c20

net/ipv4/tcp_nv.c

+4 −3
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) 
	struct tcp_sock *tp = tcp_sk(sk);

	struct tcpnv *ca = inet_csk_ca(sk);

	unsigned long now = jiffies;

	s64 rate64 = 0;

	u64 rate64;

	u32 rate, max_win, cwnd_by_slope;

	u32 avg_rtt;

	u32 bytes_acked = 0;
@@ -284,8 +284,9 @@ static void tcpnv_acked(struct sock *sk, const struct ack_sample *sample) 
	}



	/* rate in 100's bits per second */

	rate64 = ((u64)sample->in_flight) * 8000000;

	rate = (u32)div64_u64(rate64, (u64)(avg_rtt ?: 1) * 100);

	rate64 = ((u64)sample->in_flight) * 80000;

	do_div(rate64, avg_rtt ?: 1);

	rate = (u32)rate64;



	/* Remember the maximum rate seen during this RTT

	 * Note: It may be more than one RTT. This function should be