SYS_NICE is a capability that allows a process to set thread affinity
and priority, among other things (see capabilities(7) for more info).
In this commit, add a function that allows to determine if the process
has this capability, and try to change the thread affinity and priority,
if requested. If the capability does not exist, the function will simply
not attempt to change the corresponding thread attributes.
To determine if the process has SYS_NICE, libcap can be used. However,
it might not be installed by default. To avoid requiring another
dependency, if we detect that libcap is not present, use a workaround by
try to set a real-time scheduling policy; if it's present, or can be
changed, we assume that the process has SYS_NICE (and clean up, if
relevant).
Simplify reading of capabilities
set_latency_target() attempts to set keep "low latency" by
- writing a specific latency to /dev/cpu_dma_latency
- setting manually the minimum CPU processor frequency to be the maximum
There is no functionality to undo this after stopping the softmodem(s),
and most users are probably not even aware that OAI does this. It is
generally preferable to set this beforehand using a governor or by
disabling sleep states (as outlined in the tutorial, and in a follow-up
commit in the performance tuning docs).
The previous mlockall() call, to lock memory to RAM, is retained in a
new function. There were additional mlockall() calls, which have been
replaced with lock_memory_to_ram(), where necessary.
Print a clear error if a config file does not exist (unclear previously,
when the user would get a confusing, unspecific, "file I/O error" on
line 0)
I tried to free the memory that had been allocated at that point, and
verified that using the address sanitizer. Nevertheless, the function
does too much, and is too complicated for refactoring.
In a later commit, we will use find_if in L2. In the case of building
with E2 agent, we link e2_agent which comes with its own implementation
of find_if_arr(), which results in a name clash. Rename the OAI
implementation, as nothing uses this, anyway.
Add the option `--rfsimulator.prop_delay` to specify the simulated receive-path (gNB: UL, UE: DL) propagation delay in ms.
This option can be used e.g. to simulate a simple GEO satellite channel by specifying `--rfsimulator.prop_delay 238.74` to both, the gNB and the UE.
This is part of the work developed by Fraunhofer IIS within the ESA-funded project 5G-GOA (https://connectivity.esa.int/projects/5ggoa).
Memsan complains that uninitialized reads originate because of these
warnings. Most of the corresponding variables are actually read into
through by libconfig; nevertheless, initializing them should not have a
bad side-effect (because the initialized value is overwritten).
Robert Schmidt