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tcp_nv: use do_div() instead of expensive div64_u64()

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

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Konstantin Khlebnikov 2017-11-02 17:07:05 +03:00 committed by David S. Miller
parent 9d917c207d
commit 991a26af2e
1 changed files with 4 additions and 3 deletions
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7
net/ipv4/tcp_nv.c
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@ -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