"or None" would assign if the first term is false-y. But not specifying
it would already lead to the variable being set to None.

All XML steps take a single node. We can thus "centralize" reading this
parameter in the main loop and pass it to ExecuteActionWithParam().

Some CI tasks/commands like Iperf(), Ping() get multiple nodes (via XML
parameter "nodes") to potentially run UEs on different nodes (hosts) at
the same time. However, I argue that this is not good:

- we don't actually use this -- where we specify multiple UEs, it's
  always "localhost localhost..."
- it is inconsistent, as we typically have a single "node", not nodes,
  and there is a possibility to harmonize (see also next commit)
- if we needed it, there would be better ways to achieve the same.
  First, for hardware-based UEs, the ci_infra.yaml can specify different
  UEs. For simulated UEs, it would be feasible to have multiple XML
  steps run in parallel, e.g., in the XML <parallel> tag, which would
  clarify that multiple UEs on different hosts run in parallel
- it reduces code.

Hence, make a single <node> for these XML steps.

Integration `2025.w44`

* !3721 improvements in formatting and LOGs in DMRS common functions at MAC
* !3725 Handle GTP receiver errors, fix memory leaks, add CU-UP test
* !3726 fix for CSI payload sizes in PUCCH structure at UE
* CI: Adjust attenutation for HO setup
* !3728 Fix for scenario with no CSI report configured for CSI-RS
* !3731 CI: ensure clean iperf3 server startup
* !3592 Refactor PRACH handling at the gNB
* !3682 Refactor DLSCH scheduler
* !3733 Clarify whitespace
* !3706 Change registry name env var content

Closes #1015 and #1014

See merge request oai/openairinterface5g!3727

Change registry name env var content

Currently setting REGISTRY="" in a .env file results in docker failing to find
/image-name:tag. This corrects that, so it looks for local images named
image-name:tag.

Following the change to use:
  image: ${REGISTRY-oaisoftwarealliance/}${GNB_IMG:-oai-gnb}:${TAG:-develop}
the REGISTRY variable must now include the trailing slash.

Clarify whitespace

Refactor DLSCH scheduler

Refactor the DLSCH post processor similarly to what has been done in
!3521  with the goal of saving an additional iteration through all UEs,
hopefully making the DLSCH scheduler faster.

It further includes changes to make working with and debugging multi-UE
operation easier:

- add some measurements in L1 (for total TX/RX time)
- a new option MACRLCs.[0].stats_max_ue to limit the number of UEs in
  the periodic output (default: 8, 0=disable)
- avoid stack overflow in the MAC
- fix the writing of stats to nrMAC_stats.log and nrL1_stats.log when
  the written output reduces by truncating the files
- avoid to schedule retransmission with 0 RBs.

This slightly speeds up the scheduler (it e.g., does not need to check
for UEs that have retransmissions), and harmonizes with pf_ul(), which
evaluates (UL) BSR at a similar place within the scheduler.

Check and return, if necessary, that we have enough resources to make
retransmissions. Without, we can asserts in L1, such as

    Assertion (NPRB>0 && (NPRB + RBstart <= BWPsize)) failed!
    In PRBalloc_to_locationandbandwidth0() openairinterface5g/common/utils/nr/nr_common.c:506
    Illegal NPRB/RBstart Configuration (0,51) for BWPsize 51

which indicates that the scheduler requested a transmission with 0 PRBs,
which does not make sense.

Merge remote-tracking branch 'origin/rework-gnb-prach-mem-management' into integration_2025_w44 (!3592)

Refactor PRACH handling at the gNB

- Remove race conditions by correctly setting mutexes
- Fix a bug when having multiple RACH occasions
- Reduce memory footprint by removing global memory, which should also
  fix potential memory data races in FHI 7.2
- Additional fixes, see commit messages

a bit difficult to understand: sl_ahead=6 => we systematically miss the
rach detection in the scheduler because the scheduler runs more than 6
slots ahead the rx slot processing (here > 11 slots because 6 (DL and UL
slots) + 4 (RU_RX_SLOT_DEPTH, so UL only))

so, reducing sl_ahead works better than large sl_ahead because the idea
behind is: the scheduler of slot+sl_ahead will never create work to do
in a UL slot before slot+sl_ahead+X (as minimum k2 is X, in the 24PRB CI
test: 6)

saves about 600MB of memory allocation

Move the definition of PRACH items and the PRACH list to the
defs_nr_commons.h file.

Do not re-write the entire structure in nr_schedule_rx_prach(), as it is
quite large now.

Call the post-processor when the allocation is "fixed" (i.e., nothing
changes anymore), instead of having a final loop across all UEs that
might potentially be costly.

In order to calculate the PF metric, note that the statistics "reset" is
moved into pf_dl() instead of the post-processing loop, as it has to be
done on each slot.

See also: dd980302 ("Refactor to call post-processor in place")

Similarly to parent commit(s), assign sched_pdsch in a single place
instead of relying on sched_ctrl. In a follow-up commit, the
post-processor will be called in a single place.

Similarly to parent commit(s), refactor the use of NR_sched_pdsch.
Instead of using nr_mac->sched_ctrlCommon, put the NR_sched_pdsch_t on
the stack.

This also refactors update_rb_mcs_tbs() to update the existing
NR_sched_pdsch instead of updating individual fields.

This also reduces the extend to which sched_ctrlCommon is used.

As in parent commit(s).

As in parent commit.

Assign NR_sched_pdsch to sched_ctrl->sched_pdsch in one place, where the
post-processing functionality will be called in a follow-up commit. This
should result in no functional change.

It seems to be assumed that curInfo actually has the currently active
number of layers/PMI. However, I am not sure this would always be true
(e.g., UE might not have been scheduled for some slots, but number of
layers decreased as reported by CSI).  Instead, recalculate the info
from scratch when necessary.

We don't need NR_sched_pdsch here. Remove the use of it.

PF uses MCS and average throughput to decide which UE to schedule. Thus,
the first loop decides on MCS, whereas the second does the "main UE
allocation" after sorting by the PF metric.

A follow-up commit will remove sched_pusch from NR_UE_sched_ctrl_t.
Thus, we cannot rely on sched_ctrl to store the MCS in the first loop,
and look it up from there in the second. Instead, store it as part of
the UE iterator data, and take it from there.

See also: f3068caa ("Store selected MCS in UE iterator", for UL)

Introduce a struct with information on FAPI structures to save resource
and data allocation into. It's in nr_mac_gNB.h because the next commits
will reuse this for all preprocessors.

Especially in pf_dl()/pf_ul(), we use a first loop using
UE_iterator(), then iterate over a subset of UEs. It has happened a
couple of times that I was using variable "UE" (from the iterator), when
it should only be used in the first UE_iterator() loop.

Rewrite UE_iterator() to effectively limit the scope of the iterator
variables to the body of the UE_iterator. This should also make it
possible to reuse multiple UE_iterator()s with the same variables in
sequence.

CI: ensure clean iperf3 server startup

- Resolves issue with iperf3 test failure in RFSim5G multiue test
- Minor fix of iperf3 test descriptions in RFSim5G pipeline

Fix for scenario with no CSI report configured for CSI-RS

After changes in !3714 (merged), if we select to measure RSRP on SSB and not
CSI-RS (default option) and there is a single antenna port (so no MIMO report
either) we won't schedule any CSI-RS measurements for the UE. In that case
ideally we shouldn't set do_CSIRS = 1  in configuration file but still the
option is possible. So the fix is to not perform any measurements at UE on
that CSI-RS but not asserting.

Closes #1015