After much ado... The VRT branch I have always returns zero for rx_missing() and rx_overruns(), with a FIXME comment. I notice this is now fixed in the latest git.
I also found no problems of lost data using Ubuntu 9.10 on an older Zotac motherboard, it wasn't until I moved to the H55-itx, and had to get the latest e1000 ethernet driver, that the missing data issue appeared. I then had the problem using the later driver on the older motherboard, which confused me. I wil try the later git code... Checking the fractional timestamps of the received packets I found that the receive samples handler always reports the same nitems (365 in my case with a 10MHz sample rate = 3650), but the fractional count itself sometimes updates (with the new intel ethernet driver) by a multiple of this value (eg 3x), but because I'm using nitems to fwrite the data to disk, data was being skipped. I've not had a chance to check the latest git, but hopefully this is fixed. Yes, config_mimo isn't there, I was trying to go by memory, which isn't what it used to be, or ever was...:-o Yes UHD looks the way to go, but loks to be another learning curve and rewrite of code I've done already. Cheers ----- Original Message ---- From: Per Zetterberg <[email protected]> To: David Evans <[email protected]> Sent: Mon, 17 May, 2010 20:30:12 Subject: Re: [Discuss-gnuradio] USRP2 dropping data David Evans wrote: > Hi, > > setup... > -2x USRP2s + GPS 10MHz reference + 1PPS > -Single GigE port, with USRPs on GigE switch > -Zotac H55-itx MB + i3 processor, so quite high end. > -VRT branch code. I also use PPS via DCD line to trigger when to load time on > next PPS, enable real time scheduling, ref to SMA, pps to SMA, > config_mimo(MC_WE_LOCK_TO_SMA) and use similar code to rx_streaming_samples > (but 2x USRPs). > -decimation set to 10 > -feeding in same off tune carrier into RFX400s to get a sine wave, just to > observe sync. > And yet, after sampling 30 seconds of data to file from both USRPs and the > code reports 0 underruns, 0 lost packets, no S's, I often get > dropouts/missed packets. > As I am receiving only, I gather from various posts that a single eth port + > switch should be Ok. The data captured always starts off in sync, it just > goes wrong sometime during the capture. The number of bytes captured is > normally the same for both channels too. > > Hope you can help please, > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > I have used VRT and everything has worked so far. However, I didn't do "config_mimo(MC_WE_LOCK_TO_SMA)" I did "c.ref_source=usrp2::clock_config_t::REF_SMA;" and "u2->config_clock(c);". Is "config_mimo" really part of the host VRT code ? In any case, you and me should start to use UHD instead ..... _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
