diff options
| author | Eric Dumazet <[email protected]> | 2015-09-17 08:38:00 -0700 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2015-09-17 22:35:07 -0700 |
| commit | c2e7204d180f8efc80f27959ca9cf16fa17f67db (patch) | |
| tree | 1987a3905af65d2acd350038e750203f7c69cc39 /tools/perf/scripts/python/net_dropmonitor.py | |
| parent | adb094e5e7285385770eb7a7c122bfc663c5e174 (diff) | |
tcp_cubic: do not set epoch_start in the future
Tracking idle time in bictcp_cwnd_event() is imprecise, as epoch_start
is normally set at ACK processing time, not at send time.
Doing a proper fix would need to add an additional state variable,
and does not seem worth the trouble, given CUBIC bug has been there
forever before Jana noticed it.
Let's simply not set epoch_start in the future, otherwise
bictcp_update() could overflow and CUBIC would again
grow cwnd too fast.
This was detected thanks to a packetdrill test Neal wrote that was flaky
before applying this fix.
Fixes: 30927520dbae ("tcp_cubic: better follow cubic curve after idle period")
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Signed-off-by: Yuchung Cheng <[email protected]>
Cc: Jana Iyengar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/net_dropmonitor.py')
0 files changed, 0 insertions, 0 deletions