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authorWei Wang <weiwan@google.com>2018-04-26 09:58:10 -0700
committerDavid S. Miller <davem@davemloft.net>2018-04-27 14:05:36 -0400
commitc36207bd8774768fcb1de27bd06f3cd866db2421 (patch)
tree17372fa9808617883b4a8056f826eeab0b884625 /net/ipv4/tcp_output.c
parent448c907cd72acc82dab565336defe845f2e235ec (diff)
downloadlinux-c36207bd8774768fcb1de27bd06f3cd866db2421.tar.bz2
tcp: remove mss check in tcp_select_initial_window()
In tcp_select_initial_window(), we only set rcv_wnd to tcp_default_init_rwnd() if current mss > (1 << wscale). Otherwise, rcv_wnd is kept at the full receive space of the socket which is a value way larger than tcp_default_init_rwnd(). With larger initial rcv_wnd value, receive buffer autotuning logic takes longer to kick in and increase the receive buffer. In a TCP throughput test where receiver has rmem[2] set to 125MB (wscale is 11), we see the connection gets recvbuf limited at the beginning of the connection and gets less throughput overall. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 95feffb6d53f..d07c0dcc99aa 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -229,11 +229,9 @@ void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss,
}
}
- if (mss > (1 << *rcv_wscale)) {
- if (!init_rcv_wnd) /* Use default unless specified otherwise */
- init_rcv_wnd = tcp_default_init_rwnd(mss);
- *rcv_wnd = min(*rcv_wnd, init_rcv_wnd * mss);
- }
+ if (!init_rcv_wnd) /* Use default unless specified otherwise */
+ init_rcv_wnd = tcp_default_init_rwnd(mss);
+ *rcv_wnd = min(*rcv_wnd, init_rcv_wnd * mss);
/* Set the clamp no higher than max representable value */
(*window_clamp) = min_t(__u32, U16_MAX << (*rcv_wscale), *window_clamp);