Re: [Discuss-gnuradio] FreeBSD - more

[LRK]

On Thu, Oct 13, 2005 at 12:35:50AM -0700, Eric Blossom wrote:
> > 
> > I believe it was gnuradio-examples/python/usrp/benchmark_usb.py that
> > triggered the problem here.
> 
> That should be the right answer, but is not completely reliable.
 
Since I don't have a Tx board, I couldn't run that test "as is". It
tries to open the Tx board first. I'll do a little hacking on something
and then see if I encounter the problem doing something similar with
two Rx boards or opening the Rx board first.


> Try running test_usrp_standard_rx with different values of the 
> -D <decim> option.  Start with -D 128, then try -D 64, -D 32, -D 16, -D 8.
> 
>   -D 128    500kS/sec      2MB/sec
>   -D  64    1MS/sec        4MB/sec
>   -D  32    2MS/sec        8MB/sec
>   -D  16    4MS/sec       16MB/sec
>   -D   8    8MS/sec       32MB/sec
 
These tests show the apparent 4MB/s limit which Wulf has mentioned. There
also seem to be something that is related to the 4MB points in the actual
transfers. I have run tests with 3.9 MB transfers with no overruns and 
4.0 MB transfers with exactly 1. I would also expect the noverruns to go up
as -D goes down.

Clues there. Just don't know what they mean yet.

./test_usrp_standard_rx -M 1 -D 128
xfered 1.05e+06 bytes in 0.523 seconds. 2.004e+06 bytes/sec. cpu time = 0.01027
noverruns = 0
./test_usrp_standard_rx -M 1 -D 64
xfered 1.05e+06 bytes in 0.262 seconds. 4e+06 bytes/sec. cpu time = 0.009881
noverruns = 0
./test_usrp_standard_rx -M 1 -D 32
xfered 1.05e+06 bytes in 0.257 seconds. 4.085e+06 bytes/sec. cpu time = 0.009734
noverruns = 1
./test_usrp_standard_rx -M 1 -D 16
xfered 1.05e+06 bytes in 0.256 seconds. 4.09e+06 bytes/sec. cpu time = 0.009536
noverruns = 0
./test_usrp_standard_rx -M 1 -D 8
xfered 1.05e+06 bytes in 0.256 seconds. 4.089e+06 bytes/sec. cpu time = 0.009741
noverruns = 0

./test_usrp_standard_rx -M 4 -D 128
xfered 4.19e+06 bytes in 2.1 seconds. 2.001e+06 bytes/sec. cpu time = 0.03939
noverruns = 0
./test_usrp_standard_rx -M 4 -D 64
xfered 4.19e+06 bytes in 1.05 seconds. 4e+06 bytes/sec. cpu time = 0.03998
noverruns = 0
./test_usrp_standard_rx -M 4 -D 32
xfered 4.19e+06 bytes in 1.03 seconds. 4.09e+06 bytes/sec. cpu time = 0.0389
noverruns = 5
./test_usrp_standard_rx -M 4 -D 16
xfered 4.19e+06 bytes in 1.04 seconds. 4.042e+06 bytes/sec. cpu time = 0.03856
noverruns = 2
./test_usrp_standard_rx -M 4 -D 8
xfered 4.19e+06 bytes in 1.02 seconds. 4.094e+06 bytes/sec. cpu time = 0.03855
noverruns = 1

./test_usrp_standard_rx -M 16 -D 128
xfered 1.68e+07 bytes in 8.4 seconds. 1.998e+06 bytes/sec. cpu time = 0.1549
noverruns = 1
./test_usrp_standard_rx -M 16 -D 64
xfered 1.68e+07 bytes in 4.19 seconds. 4e+06 bytes/sec. cpu time = 0.1501
noverruns = 0
./test_usrp_standard_rx -M 16 -D 32
xfered 1.68e+07 bytes in 4.11 seconds. 4.078e+06 bytes/sec. cpu time = 0.152
noverruns = 20
./test_usrp_standard_rx -M 16 -D 16
xfered 1.68e+07 bytes in 4.1 seconds. 4.094e+06 bytes/sec. cpu time = 0.155
noverruns = 10
./test_usrp_standard_rx -M 16 -D 8
xfered 1.68e+07 bytes in 4.1 seconds. 4.095e+06 bytes/sec. cpu time = 0.1483
noverruns = 5



> Likewise, try test_usrp_standard_tx with different values of the 
> -I <interp> option.  Start with -I 256, then try -I 128, 64, 32, 16.
 
Can't, no Tx board.


-- 
LRK
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