all calls that manipulate the RLC and/or PDCP arrays suffer
from a high deadlock risk if a PHY worker holds the RLC
AM Rx mutex at the same time when the stack wants to carry
out this reconfiguration.
this applies to RRC Reconfigs, but potentially also to RRC Connection
Reestablishment or even RRC Connection Setup, although this should
seldom be the case.
By breaking the call stack between RLC->PDCP->RRC->RCL and
carrying out the reconfig as a single task without holding the
RLC readlock the deadlock should not happen anymore.
This should fix issue #1593
- Import the srslog project into srslte.
- Ported srsue app to use the new logging framework.
- Implemented a wrapper that dispatches log entries to srslog.
- Renamed an existing log test to be more specific to avoid name clashes.
the PSS detection needs more temporary buffer than a full subframe.
we therefore need to allocate and initialize the sync object with
larger maximum size to support Scell search of large cells, e.g.
20 MHz
this fixes issue #1538
* add locked and unlocked version of has_data() since one is
called from stack and one from PHY threads
* add comments in each interface section as to why locking
is required or not
* remove RLC rwlock when not required
* move calls only used by RRC to RRC section
as 3400 or 2.685 GHz is on the edge of band 7, some phones won't connect
to a 20 MHz cell on this EARFCN.
In order to simplify testing with other bandwidths we change the default EARFCN.
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
reducing the sync queue len to 1 caused an issue when the
PHY was locking the mutex while trying to push a TTI event
on the stack.
instead of signaling the new TTI within the PHY, we now do it outside
in the DUT (after releasing the PHY mutex)
apply same change that we've done on the eNB also on the UE
to avoid the PHY processing TTIs faster than the stack.
Without that, we see lots of those in the logs:
...
08:39:17.580325 [STCK] [W] Detected slow task processing (sync_queue_len=7).
...
before entering RRC idle, after receiving a RRC connection release for example,
we need to wait until the RLC for SRB1 or SRB2 have been flushed, i.e.
the RLC has acknowledged the reception of the message.
Previously we have only waited for SRB1 but the message can also be received on SRB2
and in this case both bearers need to be checked.
The method is now streamlined to check both SRBs and is also used when
checking the msg transmission of an detach request.
unfortunately, the rapidjson version shipped with Ubuntu 16.04
doesn't support the GetArray() API so we need to use
normal iterator to loop over the array