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From: | Aditya Dhananjay |
Subject: | Re: [Discuss-gnuradio] uhd_rx_cfile: getting constant O-overflows using the USRP B200 with debian |
Date: | Wed, 19 Mar 2014 11:08:43 -0400 |
Hi developers,
I have a fresh gnu radio installed with pybombs for my usrp B200. It runs on a Lenovo X230 with debian testing x64.
When I use uhd_rx_cfile i get constant "O"-overruns (output given below).
The uhd-benchmark runs without problems:
sudo ./benchmark_rate --duration 600 --rx_rate 32000000
So the USB3-Port isn't the Problem. Storing in ram is also fine:
sudo ./uhd_rx_cfile -f 2445000000 --samp-rate=30000000 /tmp/test.cfile
I use a Samsung Evo 840 1TB (newest firmware) and did the SSD-Optimizations (https://wiki.debian.org/SSDOptimization) while searching for the error. HDPerm-, DD- and copy-benchmarks give 500mb/s for the first seconds, later constant ~400mb/s writing speed.
Debugging with "iotop" brings (output below) 90% io-call-workload for the benchmarks, but 0% for the uhd_rx_cfile which writes only with 240mb/s. So everything should work as expected.
Btw: I also get overruns (at a lower rate) when sampling with lower sample rate and try to change the nice number.
Have you got any idea how to find and fix the bottleneck?
##################################################
address@hidden:~/tools/grc/target/bin$ sudo ./uhd_rx_cfile -f 2445000000 --samp-rate=30000000 /test/test.cfile -v
linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.007.000-1-ga8caec5f
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 32 MHz
-- Actually got clock rate 32 MHz
-- Performing timer loopback test... pass
UHD Warning:
The hardware does not support the requested RX sample rate:
Target sample rate: 30.000000 MSps
Actual sample rate: 32.000000 MSps
Using mid-point gain of 36.5 ( 0.0 - 73.0 )
Motherboard: B200 (E6R04Z7B2)
Daughterboard: B200 (RX2, A:A)
Rx gain: 36.5
Rx baseband frequency: 2.445G
Rx DDC frequency: -596.046m
Rx Sample Rate: 32M
Receiving samples until Ctrl-C
Writing 32-bit complex floats
Output filename: /test/test.cfile
OOOOOOOOOOOO
#########################################
iotop
TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
171 be/4 root 3.91 K/s 0.00 B/s 0.00 % 6.63 % [kworker/u16:3]
2656 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.04 % X :0 -auth /var/run/lightdm~olisten tcp vt7 -novtswitch
3502 be/4 root 0.00 B/s 236.78 M/s 0.00 % 0.00 % python2 ./uhd_rx_cfile -f 2~0000000 /test/test.cfile -v
########################################
address@hidden:~/tools/grc/target/bin$ sudo hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 17832 MB in 2.00 seconds = 8921.71 MB/sec
Timing buffered disk reads: 1526 MB in 3.00 seconds = 508.55 MB/sec
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