[mythtvnz] Second USB DVB-T tuner causes high load

[criggie]

Dylan Hall wrote:
> When I connect the second tuner the load average on the machine jumps to 
> 1 even when all the daemons etc have been shut down and the machine is 
> as idle as it's possible to get a linux box.

Load average is not an exact measure of how busy the machine is.
Do you have any zombie processes or anything in uninterruptable sleep?
ps auxw | egrep " D| Z"

uninterruptable sleep - a task that is waiting on disk IO normally
root    258  0.0  0.0      0     0 ?     D<   Sep14   1:06 [kswapd0]

zombie task - parent has died and not killed the child processes.
nut   17948  0.0  0.0   0     0 ?   Z   May14   0:00 [upsmon] <defunct>


Personally I've avoided USB devices just for this sort of thing.  Or try 
shutting down virtualbox and see if the tuners do anything different.

Does lsusb -t   suggest that the two tuners are together on the same 
bus?   Try moving USB ports to separate their IO from each other.

I doubt 32/64 bit is your problem, and given it only appears when there 
are two tuners, maybe its to do with the tuner kernel module.  Do you 
have another PC to run as a slave backend?

> I have VirtualBox running on the machine hosting a copy of ubuntu 9.04 
> server. With 1 tuner connected it's all good. Connect the second tuner 
> and the ping times to this virtual machine jump from <1ms to 20-60ms 
> (varying all over the place).
> 
> Despite the problems above, the second tuner appears to work fine.
> 
> The server is a Core 2 Duo E6600 2.4Ghz, 6GB Ram, running ubuntu 9.04 
> server 32 bit, kernel version 2.6.28-15-server-52.
> 
> I'm using the 32bit version of ubuntu because I'm testing SageTV for 
> linux which only ships with 32bit binaries. I have PAE enabled to get 
> access to the full 6GB of ram.
> 
> I'm unsure how to progress from here.
> 
> Any ideas anyone? seen something similar?
> 
> Should I log a bug with the ununtu people or try and track down the devs 
> for the DVB driver and log a bug with them?


-- 
Criggie

http://criggie.dyndns.org/