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Message-Id: <20190322132629.158360-1-edumazet@google.com> Date: Fri, 22 Mar 2019 06:26:29 -0700 From: Eric Dumazet <edumazet@...gle.com> To: "David S . Miller" <davem@...emloft.net> Cc: netdev <netdev@...r.kernel.org>, Eric Dumazet <edumazet@...gle.com>, Eric Dumazet <eric.dumazet@...il.com> Subject: [PATCH net-next] tcp: remove conditional branches from tcp_mstamp_refresh() tcp_clock_ns() (aka ktime_get_ns()) is using monotonic clock, so the checks we had in tcp_mstamp_refresh() are no longer relevant. This patch removes cpu stall (when the cache line is not hot) Signed-off-by: Eric Dumazet <edumazet@...gle.com> --- net/ipv4/tcp_output.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 4522579aaca2d24b7be61abac658a3c8cbd2b960..e265d1aeeb66996da3903eef383eaec9a320cce0 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -52,12 +52,8 @@ void tcp_mstamp_refresh(struct tcp_sock *tp) { u64 val = tcp_clock_ns(); - if (val > tp->tcp_clock_cache) - tp->tcp_clock_cache = val; - - val = div_u64(val, NSEC_PER_USEC); - if (val > tp->tcp_mstamp) - tp->tcp_mstamp = val; + tp->tcp_clock_cache = val; + tp->tcp_mstamp = div_u64(val, NSEC_PER_USEC); } static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, -- 2.21.0.392.gf8f6787159e-goog
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