this patch replaces the std::vector type used in the interface between
PDCP and RLC to signal delivery status between both layers. The new
data type is a configurable but fixed-size vector.
The RLC AM doesn't need to dynamically allocate the vector for every SN but
uses the tx_window for storage.
this patch fixes the actions/handling after RLC detected
maxRetx reached for a given SN.
According to the TS, RLC should only inform upper layers and
not try to recover from the event itself.
As a consequence, we won't manipulate the Tx or Rx window.
As a result of this, we might retransmit a SN more than
the specified amount of times.
It's the task of RRC to reestablish the bearer to recover
from that.
* optimize processing of status PDU (SN is removed from window immediately)
* fix maxRetx signaling for segments
* make tx_window_t a template class, rename and use for rx_window as well
* reuse vector capacity for pdcp sn notification
* use an extra lookup data structure to find PDCP SNs that an RLC SN contains
* fix rlc sn->pdcp sn lookup datastructure in rlc
* fix rlc failing test
Removing unecessary \n for logs and changed log of PDCP info queue
capacity to debug to avoid log spam.
Changed log level for unhandled S1AP messages from error to warning
in EPC to avoid failing tests because of error message.
Changed usage of allocate_unique_buffer to make_unique_buffer()
test. The race condition was being cause by write_sdu being called
simultanously to read_pdu, which could cause the read_pdu to try to get
the SDU info before it had been written by the write_sdu.
Changes in this commit include:
- Make sure PDCP sn in included in RLC AM stress test.
- Stop handling control PDU when TX is not enabled in RLC AM.
- Fixed issue with length of the PDCP SN in rlc_stress_test.
- Moved the place were sdu info erase was called to avoid double calls to erase
- Tentative fix for race condition in rlc_am_stress test.
- Added function to print information about undelivered_sdu_info_queue
for debugging.
PDCP PDUs. This includes:
- Modifying the byte_buffer_t to include PDCP SN meta-data. This way,
the RLC can keep track of the ack'ed bytes for a specific PDCP PDU.
- Added in the RLC an `undelivered_sdu_info queue`, to keep track of the
amount of ack'ed bytes and the total size of the PDCP PDU,
so the RLC can know when delivery is finished.
- Added an interface between the PDCP and the RLC so that the RLC can
notify the PDCP when it receives an ack from the status PDUs. The RLC
passes to the PDCP a vector of all the ack'ed pdus in a rx'ed status PDU.
- Added some tests to the notify functionality. This includes some tests
where the PDUs are acked imediatly, and one test where the PDU is
retx'ed.
this patch adds support for measuring the:
* SDU rx latency (Average time in ms from first RLC segment to full SDU)
* amount of buffered bytes (sum of payload of PDUs buffered in rx_window)
the implementation is using std::chrono
this patch refactors the SDU queuing and dropping policy of the RLC and PDCP layer.
the previous design had issues when packets have been generated at a higher
rate above the PDCP than they could be consumed below the RLC.
When the RLC SDU queues were full, we allowed two policies, one to block on the write
and the other to drop the SDU. Both options are not ideal because they either
lead to a blocking stack thread or to lost PDCP PDUs.
To avoid this, this patch makes the following changes:
* PDCP monitors RLC's SDU queue and drops packets on its north-bound SAP if queues are full
* a new method sdu_queue_is_full() has been added to the RLC interface for PDCP
* remove blocking write from pdcp and rlc write_sdu() interface
* all writes into queues need to be non-blocking
* if Tx queues are overflowing, SDUs are dropped above PDCP, not RLC
* log warning if RLC still needs to drop SDUs
* this case should be avoided with the monitoring mechanism
srsLTE codebot
Francisco
Andre Puschmann
Pedro Alvarez
faluco