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| author | Paolo Abeni <pabeni@redhat.com> | 2021-12-18 02:37:00 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-12-18 06:27:04 +0300 |
| commit | 3ce0852c86b926aed7bb8c69b09c5ad4ba0a9dfb (patch) | |
| tree | eba6743dcbe8ca41c57282f32ffb8d332745f81c /net/mptcp/protocol.h | |
| parent | ab9d0e2171be56bb3bcd0fe4bd8ae5d2f24e5a80 (diff) | |
| download | linux-3ce0852c86b926aed7bb8c69b09c5ad4ba0a9dfb.tar.xz | |
mptcp: enforce HoL-blocking estimation
The MPTCP packet scheduler has sub-optimal behavior with asymmetric
subflows: if the faster subflow-level cwin is closed, the packet
scheduler can enqueue "too much" data on a slower subflow.
When all the data on the faster subflow is acked, if the mptcp-level
cwin is closed, and link utilization becomes suboptimal.
The solution is implementing blest-like[1] HoL-blocking estimation,
transmitting only on the subflow with the shorter estimated time to
flush the queued memory. If such subflows cwin is closed, we wait
even if other subflows are available.
This is quite simpler than the original blest implementation, as we
leverage the pacing rate provided by the TCP socket. To get a more
accurate estimation for the subflow linger-time, we maintain a
per-subflow weighted average of such info.
Additionally drop magic numbers usage in favor of newly defined
macros and use more meaningful names for status variable.
[1] http://dl.ifip.org/db/conf/networking/networking2016/1570234725.pdf
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/137
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp/protocol.h')
| -rw-r--r-- | net/mptcp/protocol.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index e1469155fb15..0486c9f5b38b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -395,6 +395,7 @@ DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); /* MPTCP subflow context */ struct mptcp_subflow_context { struct list_head node;/* conn_list of subflows */ + unsigned long avg_pacing_rate; /* protected by msk socket lock */ u64 local_key; u64 remote_key; u64 idsn; |