diff options
author | Eric Dumazet <edumazet@google.com> | 2013-08-05 20:05:12 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-09-14 05:50:47 -0700 |
commit | dd3004635fe0607f64ca9ceca51f209fbc0a09a6 (patch) | |
tree | e570669363972e2d226941c0f4609bd9c03378ee /net/unix | |
parent | 28e9a84cdf505686ac00ead1adcbc75f26b48487 (diff) | |
download | kernel_samsung_smdk4412-dd3004635fe0607f64ca9ceca51f209fbc0a09a6.zip kernel_samsung_smdk4412-dd3004635fe0607f64ca9ceca51f209fbc0a09a6.tar.gz kernel_samsung_smdk4412-dd3004635fe0607f64ca9ceca51f209fbc0a09a6.tar.bz2 |
tcp: cubic: fix bug in bictcp_acked()
[ Upstream commit cd6b423afd3c08b27e1fed52db828ade0addbc6b ]
While investigating about strange increase of retransmit rates
on hosts ~24 days after boot, Van found hystart was disabled
if ca->epoch_start was 0, as following condition is true
when tcp_time_stamp high order bit is set.
(s32)(tcp_time_stamp - ca->epoch_start) < HZ
Quoting Van :
At initialization & after every loss ca->epoch_start is set to zero so
I believe that the above line will turn off hystart as soon as the 2^31
bit is set in tcp_time_stamp & hystart will stay off for 24 days.
I think we've observed that cubic's restart is too aggressive without
hystart so this might account for the higher drop rate we observe.
Diagnosed-by: Van Jacobson <vanj@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/unix')
0 files changed, 0 insertions, 0 deletions