[Discuss-gnuradio] Transmitter's bizarre behavior on 64 bit workstation

[Andrew Ge]

 Eric,

I found a puzzling fact about running GNU Radio on the 64-bit Lenovo 
workstation D20.

Basically, the maximum packet size (payload at the transmitter side in 
the benchmark_tx.py) must be less than or equal to 221. Below this size, 
packets from the workstation can be correctly received by either a 
laptop or another workstation; above this size, no packet can be 
received correctly on either a laptop or another workstation.  I was 
using 500kb data rate and GMSK modulations.

The same code works perfectly on a laptop as the transmitter, no matter 
the receiver side is on a laptop or a workstation.

At first, I thought it might be a result of the quad core (8 CPUs)  
architecture. So I disable 3 cores and only one core was left. However, 
I got the same result.

Also, the CPU usage for a transmitter doesn't make sense to me either. 
It was above 90% on the workstation (2 Intel Xeon X5550 cpus at 2.67 
GHz). However it was only around 35% on the laptops (2 Intel T9550 CPUs 
at 2.66GHz).

I could not understand what might be the problem.

Andrew