diff options
author | Eric Dumazet <edumazet@google.com> | 2015-02-26 14:10:20 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2015-02-28 15:10:39 -0500 |
commit | a0ea700e4095e26a8e291374757dd29519900f18 (patch) | |
tree | 5dc19465848a991d8baf2ac3cac3079c92baef5f /mm/memcontrol.c | |
parent | 50c8339e9299aaf09e48c8f94de39baec638c874 (diff) |
tcp: tso: allow CA_CWR state in tcp_tso_should_defer()
Another TCP issue is triggered by ECN.
Under pressure, receiver gets ECN marks, and send back ACK packets
with ECE TCP flag. Senders enter CA_CWR state.
In this state, tcp_tso_should_defer() is short cut :
if (icsk->icsk_ca_state != TCP_CA_Open)
goto send_now;
This means that about all ACK packets we receive are triggering
a partial send, and because cwnd is kept small, we can only send
a small amount of data for each incoming ACK,
which in return generate more ACK packets.
Allowing CA_Open and CA_CWR states to enable TSO defer in
tcp_tso_should_defer() brings performance back :
TSO autodefer has more chance to defer under pressure.
This patch increases TSO and LRO/GRO efficiency back to normal levels,
and does not impact overall ECN behavior.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'mm/memcontrol.c')
0 files changed, 0 insertions, 0 deletions