As it says in rfc8260#section-3.6 about the weighted fair queueing
scheduler:
A Weighted Fair Queueing scheduler between the streams is used. The
weight is configurable per outgoing SCTP stream. This scheduler
considers the lengths of the messages of each stream and schedules
them in a specific way to use the capacity according to the given
weights. If the weight of stream S1 is n times the weight of stream
S2, the scheduler should assign to stream S1 n times the capacity it
assigns to stream S2. The details are implementation dependent.
Interleaving user messages allows for a better realization of the
capacity usage according to the given weights.
This patch adds Weighted Fair Queueing Scheduler actually based on
the code of Fair Capacity Scheduler by adding fc_weight into struct
sctp_stream_out_ext and taking it into account when sorting stream->
fc_list in sctp_sched_fc_sched() and sctp_sched_fc_dequeue_done().
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
As it says in rfc8260#section-3.5 about the fair capacity scheduler:
A fair capacity distribution between the streams is used. This
scheduler considers the lengths of the messages of each stream and
schedules them in a specific way to maintain an equal capacity for
all streams. The details are implementation dependent. interleaving
user messages allows for a better realization of the fair capacity
usage.
This patch adds Fair Capacity Scheduler based on the foundations added
by commit 5bbbbe32a4 ("sctp: introduce stream scheduler foundations"):
A fc_list and a fc_length are added into struct sctp_stream_out_ext and
a fc_list is added into struct sctp_stream. In .enqueue, when there are
chunks enqueued into a stream, this stream will be linked into stream->
fc_list by its fc_list ordered by its fc_length. In .dequeue, it always
picks up the 1st skb from stream->fc_list. In .dequeue_done, fc_length
is increased by chunk's len and update its location in stream->fc_list
according to the its new fc_length.
Note that when the new fc_length overflows in .dequeue_done, instead of
resetting all fc_lengths to 0, we only reduced them by U32_MAX / 4 to
avoid a moment of imbalance in the scheduling, as Marcelo suggested.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
