Just for comparison, I can easily do 10 Msps with a Beagleboard X-15 and
B210. Also, benchmark_rate works fine at 20 Msps. This is without Thread
Priority Scheduling.
I'm also using X forwarding (with a wired 1 Gbps Ethernet connection).
The GUI Frequency Sink is sending 120 Mbps over the network.
Some items I'm using.
1) "recv_frame_size=16360, num_recv_frames=128" in the UHD USRP Source block
Device Address.
2) I'm building UHD with specific NEON flags. The Beagleboard X-15 has a
2-core 32-bit armv7 processor at 1.5 GHz.
cmake -DCMAKE_CXX_FLAGS:STRING="-march=armv7ve -mfloat-abi=hard
-mfpu=neon-vfpv4 -mtune=cortex-a15 -Wno-psabi"
-DCMAKE_C_FLAGS:STRING="-march=armv7ve -mfloat-abi=hard -mfpu=neon-vfpv4
-mtune=cortex-a15 -Wno-psabi" -DCMAKE_ASM_FLAGS:STRING="-march=armv7ve
-mfloat-abi=hard -mfpu=neon-vfpv4 -mtune=cortex-a15 -g" ../
You could try some other options for the Pi4, especially if you're using
a 64-bit OS.
-march=armv8-a or -march=native
-mtune=cortex-a72
-mfpu=neon-fp-armv8
Unfortunately, I don't have a Pi4 test these options with.
Ron
On 9/29/20 17:00, Arthur Lobo via USRP-users wrote:
Hi All:
I installed UHD 4.0 and GRC 3.9 on a Raspberry Pi 4B following the
procedure at:
https://wiki.gnuradio.org/index.php/InstallingGRFromSource_on_Raspberry_Pi
However I did not specify DNEON_SIMD_ENABLE=OFF in the command cmake
-DNEON_SIMD_ENABLE=OFF -DCMAKE_INSTALL_PREFIX=/usr/local ../
while building UHD.
I also set the CPU Governor and Thread Priority Scheduling according to:
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks
Testing USRP Source->Frequency Sink in GRC at 4 MSPS with a B205mini
on a headless RPI (X forwarding to
a NUC7i7BNH PC) over USB3 shows an update rate (spectrum refresh rate
on the display) of once per second and at 10 MSPS freezes.
Running benchmark_rate at 20 MSPS will cause ERROR_CODE_TIMEOUT messages.
I also overclocked the RPi4B to 2.2 GHz with the same result.
Any suggestions to get higher sampling rates with the RPi4B-B205mini
setup?
Thanks.
Arthur
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