On 21/04/2009, at 3:47 AM, Andrew Ford wrote: > Hi Chris, > > After some testing we've seen this happen with multiple IVCs and > multiple machines - at any rate, we don't have any more spare linux > boxes to test with. I have a feeling it might be related to Ubuntu's > CPU frequency scaling though, as I've never seen it freeze when I > manually set it to use the maximum clock speed. What are the clock > settings on your machine?
Andrew, Did you roll your own kernel? When I tried to add the cpu frequency scaler applet, it reports that I don't have it set in the kernel - since I try to keep our build machines as standard as possible (i.e. only latest supplied kernels) and if frequency scaling is working for you, I'm guessing you have a non-standard kernel. In that case I suggest you revert to a standard kernel to test whether the freeze effect goes away. Either the frequency scaling itself or the change of some other kernel option may be causing the freeze effect; reverting to a standard kernel could rule those changes out as the cause. > Also, as a side note, does anyone know how to set the default on > boot to be max clock speed? The gnome-power-manager menu in gconf- > editor doesn't have any options for setting CPU frequency. In my case, without frequency scaling enabled in the kernel, the scaler applet works in read only mode. From that, I could see that the clock setting is set to 100%. BTW it looks from the applet like the frequency scaling could be set to different values on different cores of a multicore machine - that may also contribute to the freezing. chris > 2009/3/29 Christoph Willing <[email protected]> > > On 26/03/2009, at 4:58 PM, Christoph Willing wrote: > > > On 26/03/2009, at 3:34 AM, Andrew Ford wrote: > > Hi, > > For a while now we've been seeing hard freezes (ie, trying to kill > the X server does nothing) on one of our Linux machines when it > tries to send video via an IVC-200 cap card. It tends to occur more > frequently when the load is heavier - attempting to send 2 or more > 720x480 mpeg4 or h.264 streams causes it to freeze within 5-10 > minutes, 4 h.261 videos make it freeze in about half an hour, and 2 > 261 videos makes it last about 2 days. dmesg and /var/log/messages > don't give any clues. Other types of load don't seem to cause > freezes, and I ran memtest86 overnight with no errors. Originally > the machine was Ubuntu 8.04 64-bit, then 8.10 64-bit, then 8.10 32- > bit, and the problem was seen in all 3. In all cases it was running > the UQ-provided AG 3.2beta with the stock VideoProducer services. I > know there was a bttv driver deadlock issue in kernels pre-2.6.24, > but this is running kernel 2.6.27 so that shouldn't be the problem. > > Also when sending video on that machine occasionally the stream > would start to flicker, flashing an old frame alternating with the > current output of the camera. Has anyone seen either of these issues > before? > > > Andrew, > > I just installed a 32bit Ubuntu 8.10 on the UQVislab node's video > capture machine. I've been running 2x mpeg4 streams and an h261 > stream for over two hours. I just powered the machine down to > confirm it is actually an IVC-200G card (it is). After the restart, > I've now configured it to run with 3x mpeg4 streams. These are full > PAL streams 704x576. Its been running for nearly 10 minutes now - > will leave it running overnight (in the APAG lobby, if you want to > check on them) and report back. Based on the previous successful 2 > hour test, I think this 3 large streams test will be OK too. > > > Andrew, > > We've now had this setup (32bit Ubuntu 8.10 with IVC-200G streaming > 3x mpeg4 streams @ 704x576) running continuously for over three days > now without any discernible problem. That result suggests a hardware > issue with your capture card (or even the machine itself). > > > chris > > > > > You could try reseating the card - maybe some dust or contact > oxidation is creating some bad effect? Do you have any similar > capture cards lying around you could temporarily replace the IVC > with? That may indicate whether you have a card fault or machine/OS > fault. > > > chris > > > Christoph Willing +61 7 3365 8316 > QCIF Access Grid Manager > University of Queensland > > > Christoph Willing +61 7 3365 8316 > QCIF Access Grid Manager > University of Queensland > > Christoph Willing +61 7 3365 8316 QCIF Access Grid Manager University of Queensland
