[mythtv-users] possible alternative to HDhomerun? TBS MOI

Alan Young ayoung at teleport.com
Fri Apr 12 02:23:03 UTC 2013


Russell Gower wrote:
>
> Yes it is a single core CPU and it only has 512mb of RAM, whilst typing this I've realised it's only using 384MB, looks like 128MB is being allocated to a frame buffer!, heres an extract from TOP whilst recording two programmes
>
> top - 07:54:47 up 16:55,  2 users,  load average: 4.35, 2.11, 1.44
> Tasks:  63 total,   1 running,  62 sleeping,   0 stopped,   0 zombie
> %Cpu(s): 18.8 us, 23.8 sy,  0.0 ni,  7.6 id, 13.5 wa,  0.0 hi, 36.3 si,  0.0 st
> KiB Mem:    350308 total,   327412 used,    22896 free,     1360 buffers
> KiB Swap:        0 total,        0 used,        0 free,   129424 cached
>
>   PID USER      PR  NI  VIRT  RES  SHR S  %CPU %MEM    TIME+  COMMAND                                                                     
>  2158 mythtv    20   0  593m 165m 2628 S  52.6 48.4  71:45.02 mythbackend                                                                 
>    16 root      20   0     0    0    0 S  26.1  0.0   5:40.12 rpciod/0                                                                    
>
> I've tried using various mount options including the defaults and those that the master backend uses, I stopped trying to tune NFS when I released the NIC was only managing half it's theoretical throughput, i've checked and it is running 100/Full duplex it's connected to the same switch as the Master backend and the NFS server.
>
> To clarify I'm running the Wheezy user space but I have to use the TBS kernel tree as the tuner drivers are only supplied as .o objects against that tree, I did have to do a small patch to the kernel to stop udev complaining about a missing system call.
>
> My next move is to put back the stock firmware and redo the IPERF benchmarks if there is no improvement I'll contact moi support again (they've been very helpful so far).
>
> Cheers
>   Russell
>   

Nice find.  A streaming device should probably not allocate a frame 
buffer in production.  Hopefully that's a hardware configuration they 
can turn off or reduce the frame size to give back memory to the 
system.  Still if it can't be adjusted, it looks like there's fair 
amount of ram available and swap hasn't been touched.  There are a 
couple of black connectors on the board picture that appear suspiciously 
like they could be video connectors...

The TOP snapshot looks good.  The total CPU% is low so there is plenty 
of room for the single core to handle the work.  The 13.5% i/o wait 
percentage seems high.  It would be interesting to see if that is high 
during a IPERF test without anything else running.

Alan


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