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| author | Kevin O'Connor <kevin@koconnor.net> | 2017-07-21 23:49:44 -0400 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2017-07-21 23:49:44 -0400 |
| commit | d469db84ee2035c3f5d10d3072cdbddcbc94cbe9 (patch) | |
| tree | 9da02277e6aeb99f9a7e7314cbcced8ee587b4f3 /klippy/serialqueue.c | |
| parent | 4655a6bfef4b87b3674cafcbe8e8d2debadf3cbf (diff) | |
| download | kutter-d469db84ee2035c3f5d10d3072cdbddcbc94cbe9.tar.gz kutter-d469db84ee2035c3f5d10d3072cdbddcbc94cbe9.tar.xz kutter-d469db84ee2035c3f5d10d3072cdbddcbc94cbe9.zip | |
serialqueue: Allow a second nak after a retransmit
If a nak message causes a retransmission then also accept a second nak
message as long as it is for a sequence greater than the first nak.
This should allow faster retransmits when there are multiple
transmission errors in a small time period.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Diffstat (limited to 'klippy/serialqueue.c')
| -rw-r--r-- | klippy/serialqueue.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/klippy/serialqueue.c b/klippy/serialqueue.c index 5886f8e1..6271911b 100644 --- a/klippy/serialqueue.c +++ b/klippy/serialqueue.c @@ -347,7 +347,7 @@ struct serialqueue { double last_receive_sent_time; // Retransmit support uint64_t send_seq, receive_seq; - uint64_t retransmit_seq, rtt_sample_seq; + uint64_t ignore_nak_seq, retransmit_seq, rtt_sample_seq; struct list_head sent_queue; double srtt, rttvar, rto; // Pending transmission message queues @@ -492,7 +492,7 @@ handle_message(struct serialqueue *sq, double eventtime, int len) if (rseq != sq->receive_seq) // New sequence number update_receive_seq(sq, eventtime, rseq); - else if (len == MESSAGE_MIN && rseq > sq->retransmit_seq + else if (len == MESSAGE_MIN && rseq > sq->ignore_nak_seq && !list_empty(&sq->sent_queue)) // Duplicate sequence number in an empty message is a nak pollreactor_update_timer(&sq->pr, SQPT_RETRANSMIT, PR_NOW); @@ -581,10 +581,18 @@ retransmit_event(struct serialqueue *sq, double eventtime) sq->bytes_retransmit += buflen; // Update rto - if (pollreactor_get_timer(&sq->pr, SQPT_RETRANSMIT) != PR_NOW) { + if (pollreactor_get_timer(&sq->pr, SQPT_RETRANSMIT) == PR_NOW) { + // Retransmit due to nak + sq->ignore_nak_seq = sq->receive_seq; + if (sq->receive_seq < sq->retransmit_seq) + // Second nak for this retransmit - don't allow third + sq->ignore_nak_seq = sq->retransmit_seq; + } else { + // Retransmit due to timeout sq->rto *= 2.0; if (sq->rto > MAX_RTO) sq->rto = MAX_RTO; + sq->ignore_nak_seq = sq->send_seq - 1; } sq->retransmit_seq = sq->send_seq - 1; sq->rtt_sample_seq = 0; |