Josh,
Thanks for pointing out the time function library, which I actually
intended to call for printout analysis. As shown below, the huge delay
was not caused by the WORK function's SEND. I am still trying to figure
out the root, will let you know once I have it.
Andrew
SEND:
ping 192.168.200.1 -i 0.5
PING 192.168.200.1 (192.168.200.1) 56(84) bytes of data.
64 bytes from 192.168.200.1: icmp_req=1 ttl=64 time=7.34 ms
64 bytes from 192.168.200.1: icmp_req=2 ttl=64 time=507 ms
^C
--- 192.168.200.1 ping statistics ---
4 packets transmitted, 2 received, 50% packet loss, time 1515ms
rtt min/avg/max/mdev = 7.340/257.186/507.033/249.847 ms, pipe 2
RECV
Rx: ok = True len(payload) = 98, time 1299249666.140256
Tx: len(payload) = 98, time 1299249666.140396
gr_uhd_usrp_sink::work() 1920
time before send() 1341920.684302
time after send() 1341920.684409
Rx: ok = True len(payload) = 98, time 1299249666.641308
Tx: len(payload) = 98, time 1299249667.140895
gr_uhd_usrp_sink::work() 1920
time before send() 1341930.684843
time after send() 1341930.684949
Rx: ok = False len(payload) = 98, time 1299249667.148811
Rx: ok = True len(payload) = 98, time 1299249667.656015
Tx: len(payload) = 98, time 1299249668.141481
gr_uhd_usrp_sink::work() 1920
time before send() 1341940.685471
time after send() 1341940.685581
On 03/04/2011 12:19 AM, Josh Blum wrote:
As such, do you know an approach to solve this blocking problem? I have
tried to set the timeout as a small value, e.g. 1ms, but it seems not
able to completely solve the problem. I have never seen such behavior
using the raw Ethernet code. What's the difference?
Andrew,
The uhd_usrp_sink::work() should always block until the entire buffer
has been transmitted. There is no choice in the matter. However many
samples gnuradio buffered before calling work(), we must send all of
those samples.
Now, there is a question of where is the delay, what is taking too long,
what is buffering too much, etc. I am attaching a diff with prints for
the time before and after the send() call in the work function. This
will tell us how often work is called, how many samples are transmitted,
and how long this operation takes. Please try the attached diff and post
the output.
Thanks,
-Josh
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