This commit enables the optional use of Tracy for profiling NR UE & gNB.
See https://github.com/wolfpld/tracy/releases/tag/v0.11.1 for details.
How to compile:
use -DTRACY_ENABLE=ON to enable instrumentation and sampling
For gNB currently only sampling is implemented.
How to collect data:
- Windows hosts: tracy-profiler.exe in link above
- Linux hosts: Compile tracy-profiler from source
Enabling collection from docker:
- open port 8086
- to collect cpu data
--privileged
--mount "type=bind,source=/sys/kernel/debug,target=/sys/kernel/debug,readonly"
--user 0:0
--pid=host
How to add instrumentation:
- See examples in this commit or manual in the link above.
- if search fails, keeps increasing the rx gain (set by --ue-rxgain) by
3 db until USRP max rx gain
- if initial sync is success, sets the rxgain to the value of
(TARGET_RX_POWER (50) - pbch digital power in dB/RE)
- Phy config update and Sidelink frame parameters initialisation
- PSBCH scheduler to trigger TX PSBCH/RX PSBCH actions
- Sidelink indication with rx ind to trigger send SL-MIB to MAC
- Enable Scope for PSBCH use -d or --dqt
- Enable system testing of PSBCH for example using RFSIMULATOR:
- UE1 is a SYNCRONISATION SOURCE UE which transmits PSBCH
started using command -
sudo ./nr-uesoftmodem --sl-mode 2 --sync-ref 4 --rfsim --rfsimulator.serveraddr server
- UE2 syncs onto UE1 during sidelink search, gets the timing and continues to receive PSBCH
started using command -
sudo ./nr-uesoftmodem --sl-mode 2 --rfsim --rfsimulator.serveraddr 127.0.0.1
- In the default use case 2 Sidelink SSBs sent over 16 frames.
- In case SL-SSB configuration needs to be changed use -O option in the above command like
-O ../../../targets/PROJECTS/NR-SIDELINK/CONF/sidelink_preconfig_1txpool.conf
Till this commit, the UE gets the position of SSB in frequency from
command line and does the syncronization by locating the SSB in time. It
does this by generating a PSS time signal during initialization with the
SSB offset given via command line. Then PSS detection is done by
correlation.
In this commit, the UE computes a list of GSCN in the current NR band
that falls within the current bandwidth for the set center frequency.
For each GSCN in the list, the UE starts a thread and performs the
following:
1. Generate PSS time signal with SSB offset for current GSCN.
2. Detect PSS, SSS and decode PBCH (this step remains the same).
After all threads finishes, the results are collected.
For now, only the first detected PBCH is used to proceed further. So
this PBCH is indicated to MAC and UE exits initial sync.
Future work: The cell search can be standalone feature where the UE
could scan for SSB in the entire NR band. This would require changing
radio's frequency on the fly as the UE's bandwidth would not cover an
entire NR band. The cell detection can futher be imporved by looking
for SIB1 for each decoded PBCH.
Laurent THOMAS